Botany
https://repository.maseno.ac.ke/handle/123456789/34
2024-03-29T15:59:32ZEffect of Npk blended fertilizer application on soil physico-chemical properties, growth, physiology and yield of two finger millet (eleusine coracana l. gaertn.) varieties grown in acidic soils of Kakamega western Kenya.
https://repository.maseno.ac.ke/handle/123456789/5706
Effect of Npk blended fertilizer application on soil physico-chemical properties, growth, physiology and yield of two finger millet (eleusine coracana l. gaertn.) varieties grown in acidic soils of Kakamega western Kenya.
SIMIYU, Wamalwa Dennis
Finger millet is one of the most important cereal crops in Kenya. It is staple food rich in minerals and vitamins required for good health. Finger millet is a hardy crop compared to other cereals and it is for this reason that its currently being promoted in efforts to address food security. Western Kenya soils are acidic and soil acidity is a serious problem that affects crop productivity. County governments of Kakamega, Bungoma, Vihiga, Busia and Trans-Nzoia are promoting soil application of NPK blended fertilizer (10%N, 26%P, 10%K2O, 4%S, 8%CaO, 4%MgO and traces of B, Zn, Mo, Cu and Mn) to ameliorate the soil acidity. However, it is not known how the fertilizer affects soil, plant growth, physiology and crop yield. The study aimed to investigate the effect of NPK blended fertilizer application on the soil physio-chemical properties, growth, physiology and yield of finger millet in acidic soils of Kakamega. Experiments were conducted at the crop and livestock research field of Kenya Agricultural and Livestock Research Organization(KALRO) Kakamega station. Experiments were conducted during the short (October-January) and long (March-August) rainy seasons of 2015 and 2016 respectively. A Randomized Complete Block Design, involving application of 0,25,50,75 and 100 kg per acre of NPK blended fertilizer as the treatments. Two equal split application were done. Selected finger millet varieties of P-224 and Gulu-E which were sourced from KALRO-Kakamega. The varieties are commonly grown in Western Kenya and were known to be early maturing and drought resistant. Data was collected on soil pH, soil Aluminium, Calcium and Magnesium, finger length, finger width, plant height, days to 50% flowering, productive tillers, grain yield, chlorophyll content index and plant tissue nitrogen, phosphorus, potassium, magnesium, calcium were collected. Data collected was subjected to Analysis of Variance using GenStat statistical package version 15.1. Treatment means were separated at 5% probability level where significant differences (P≤0.05) were observed using the LSD test. Application of NPK blended fertilizer significantly reduced the amount of soil aluminium for both season with the highest reduction recorded under the 100 kg per acre fertilizer application. The soil pH, soil calcium and soil magnesium significantly (P≤0.05) increased linearly with increasing fertilizer rates. The application of NPK blended fertilizer significantly increased the plant height, finger length and finger width of both varieties. At the 75 kg/acre rate the leaves showed significantly highest total chlorophyll content in both varieties with the highest (29.17 umol) under variety P-224. The control showed the lowest physiological activities in terms of chlorophyll content, calcium, magnesium, nitrogen, phosphorus and potassium. Period to 50% flowering were significantly reduced due to application of NPK blended fertilizer where Gulu-E had 80 days at the highest rate while P-224 had 81 days on the same rate. At 50 kg/acre, the number of days to physiological maturity were significantly (P≤0.05) reduced under both varieties where Gulu-E took 107 days to mature. The number of productive tillers were significantly increased with increasing NPK blended fertilizer application rate especially under Gulu-E variety with a high number of 42 productive tillers per plot. The grain yield was significantly increased by application of NPK blended fertilizer with the peak observed at the 75 kg/acre rate for both varieties but Gulu-E outperformed P-224, therefore Gulu-E may be recommended to farmers due to its increased yield of 1.55 ton/ha. Farmers can improve finger millet yield and enhance their incomes while sustaining their soil fertility by using NPK blended fertilizer. The study concluded that application rate of 75 kg/acre of NPK fertilizer leads to the highest grain yield potential of finger millet varieties and positive liming effects that may ultimately reduce acidity of soils in the western Kenya region.
2018-01-01T00:00:00ZMelliferous taxa, floral calendar, Melissopalynology, and organoleptic characterization of aboriginal Ogiek honey in the eastern Mau forest block, Kenya
https://repository.maseno.ac.ke/handle/123456789/5225
Melliferous taxa, floral calendar, Melissopalynology, and organoleptic characterization of aboriginal Ogiek honey in the eastern Mau forest block, Kenya
OMONDI, Philip Onyango
Mau forest is one of the five water towers in Kenya serving as a critical catchment area for rivers and lakes in both Kenya and Tanzania. It plays a critical role in livelihood support. Eastern Mau forest has experienced most of the deforestation, loss of ecosystem vitality and biodiversity due to non-inclusion of local community in the conservation efforts. The Kenyan government legislative and policy frameworks have acknowledged the need for involvement of the Ogiek community. The community have long lived in the forest and area knowledgeable in forest conservation and bee keeping. Beekeeping by the Ogieks has been recommended under livelihood support programs to reduce destructive forest exploitation, this is by lack of information on: the authenticity of botanical and geographical origin of the Ogiek honeys, floral calendars to enhance apiary management and, organoleptic profile to enable sale in regulated honey markets. The objective of this study was to characterize melliferous flora, the botanical and geographical origin of Ogiek honeys and their organoleptic profile. A simple stratified random sampling research design was adopted with Kapkembu, Nessuit, and Mariashoni areas, Eastern Mau as the strata. The Ogiek bee keepers’ hives were the source of honey samples. Ten grams of each of the twenty-seven honey samples collected from Eastern Mau forest formed the unit of analysis. Approved methods of honey analysis were used. Collection of field data for development of floral calendar adopted belt transects around selected bee colonies for twelve months. Data was subjected to Analysis of Variance, Tukeys honestly significant difference post-hoc test, multivariate analysis, Jaccards similarity coefficient, quantitative descriptive analysis, and two-step cluster algorithms on SPSS base 20. Means of organoleptic data was subjected to Friedman’s test. Total of eighty-six plant species are foraged by Apis mellifera. Cissus rotundiflora Vahl. (Vitaceae), Trema orientalisL. (Ulmaceae), Maerua triphyllaA. Rich (Capparaceae), Aloe secundiflora Engl. (Asphodelaceae), Tribulis terrestisL. (Zygophyllaceae) and Polyscias fulvaJ.R. Forst. and G. Forst. (Araliaceae) are reported for the first time in Eastern Mau. Trees formed 41.86%, Herbs (25.58%), Shrubs (23.25%), and climbers (9.3%) of the bee forage. The peak availability of forage from the floral calendar was in April and May (2016) during the study. The Acacia species provide successive bloom mosaic year round. The highest similarity was observed in a comparison between (NE-S3-8) and NE-S1-8) within same site. The mean number of pollen types were highest in April (12.8), and lowest in December (9.7). There is a significant positive correlation (r=0.607*, 0.05) between number of pollen types and pollen density. Mean Shannon weaver diversity index was 2.32 across all seasons and sites of sample collection. Vernonia auriculifera, Cordia abyssinica, Acacia spp were very frequent pollen types, with Acacia type pollen having 85.2% frequency of occurrence in the honey samples. The rare, infrequent, frequent, very frequent pollen types observed in this study constitute the pollen spectrum that determine the geographical origin of Ogiek honeys in Eastern Mau forest. Botanical origin from predominant pollen types were Acacia spp type, Eucalyptus type, Croton spp. type, Albizia coriaria type, Cordia abyssinica type, and Vernonia auriculifera type. Floral fresh aroma family was the most dominant in 50% of the unifloral honey samples represented by Acacia, Croton and Albizia honey. Friedman’s test (N=12, df=7, X2 =14.07, Least Significant Difference= 23.52) revealed a significant difference in the sum of rankings in all organoleptic attributes. This study provides significant information on the floral calendar, unifloral and multifloral botanical origin as well as pollen spectrum denoting the geographical origin, and an organoleptic profile of unifloral Ogiek produced honeys Eastern Mau. The information from this study is important for extension services and policy development.
2019-01-01T00:00:00ZThe effects of ocimum gratissimum, ipomoea batatas And brassica oleracea var botrytis extracts on the Growth and disease-causing capability of ralstonia Solanacearum in solanum tuberosum
https://repository.maseno.ac.ke/handle/123456789/5207
The effects of ocimum gratissimum, ipomoea batatas And brassica oleracea var botrytis extracts on the Growth and disease-causing capability of ralstonia Solanacearum in solanum tuberosum
WAGURA, Alice Gathoni
Irish potato (Solanum tuberosum L.) is a major cash and food crop worldwide. The
production of this crop has in a great way been negatively affected by the extensive
spread of bacterial wilt that is caused by Ralstonia solanacearum with over 50% crop
yield losses reported in the last two decades. In addition, no bactericide has been
developed to combat the disease and exercise of integrated control measures have not
resulted to a sustainable solution. Scientists are putting a lot of efforts in research to get a
solution that is effective, environmental friendly and that will enable the capacity of food
production be improved to cater for the increasing human population. Plants have been
shown to contain principles which are active against pathogens and among them are
Brassica, Ipomoea and Ocimum species. It is on this basis that this research was aimed at
determining the efficacy of locally available plants extracts in controlling the bacterial
wilt disease in potatoes. The study was carried out in Maseno University Botany &
Horticulture Department laboratory and the institution's Botanic Garden in 2007. The
pathogen was isolated from infected potato tubers and cultured on nutrient agar medium.
Ethyl acetate and methanol extracts of leaves of Ocimum gratissimum, Ipomoea batatas
and Brassica oleracea var. botrytis and essential oils of. Ocimum gratissimum were
evaluated for their efficacy at concentrations of 0.4, 0.2, 0.1, 0.05 and 0.025 mg/ml
dissolved in dimethylsulphoxide in inhibiting in vitro growth of wilt bacteria. The
experiment was extended to greenhouse where aqueous extracts of the three plants at
concentrations of 2.5, 5 and 10% were evaluated for their efficacy in controlling the
development of bacterial wilt symptoms on inoculated potato plants with control plants
being inoculated with no treatment subjected to them. The extracts were also evaluated
for their effect on different potato plants parameters. The experimental set up was randomized completely block design with 12 treatments and three replications. Data
collectedwas subjected to Analysis of Variance (ANOVA) using SAS statistical package
and the effects declared significant at 5% level. Linear correlation was used to compare
the relationship between variables. The study has proved that the three plants contains
principles that are active against wilt bacteria with essential oils from Ocimum
gratissimum at O.4mglml exhibiting highest activity (10.lmm inhibition diameter) and
Ipomoea batatas methanol extract at 0.025mglml exhibiting zero inhibition. The
laboratory study has also shown a highly significant (P < 0.0001) interaction among
plants, solvents and the various concentrations in the inhibitory activity. Aqueous extracts
of the three plants have also exhibited varying levels of controlling wilt symptoms and
promoting potato growth. The extracts of Ocimum at 10% and Brassica at 5% were the
most effective in controlling the development Of wilt symptoms with average wilting
index of 1.33 meaning less than 50% wilting occurrence. Potato plants treated with
Brassica extracts at 10% exhibited an abnormal character of its leaf tips drying and thus
.affecting their growth. In assessing the effect of potato wilting, the interaction between
the plant and various concentrations was shown not to be significant (P> 0.05) in the first
four days after inoculation. However it was significant (P<O.001) in the following three
days and highly significant (P< 0.0001) after and until the end of the study period. The
crude extracts had a significant effect on the growth parameters of potato. Based on the
findings of this study the three plants contains compounds that are active against the
growth of wilt bacteria and we recommend further evaluation of the crude extracts to
determine the actual active ingredients which can be used to develop an effective
biocontrol agent for this disease.
2010-01-01T00:00:00ZEvaluation of phenetic characters ·and growth Performance of native wood ear mushrooms (Auricularia species) on partially composted Agricultural wastes
https://repository.maseno.ac.ke/handle/123456789/5198
Evaluation of phenetic characters ·and growth Performance of native wood ear mushrooms (Auricularia species) on partially composted Agricultural wastes
ONYANGO, Benson Odhiambo
Wood ear mushrooms (Auricularia species) are a group of jelly fungi which occur as
saprophytes on stumps or at the bases of dead or dying woody trees found in tropical regions.
They have an ear shaped fruiting body from which they derive their common name. In other
parts of the world, wood ear mushrooms have been domesticated and are valued for their
nutritional and medicinal properties. Kenyan indigenous wood ear ~nushrooms which occur
abundantly in Kakamega Forest have not been studied to evaluate their cultivation potential.
Currently, the indigenous wood ear mushrooms face a threat of depletion due to over harvesting
by the rural populace and rampant forest destruction. There is need to investigate their
domestication potential in order to conserve their genetic resource. The objectives of this study
were to evaluate the genetic diversity and to develop cultivation protocols for the indigenous
wood ear mushrooms on malt extract agar, millet and sorghum grains and partially composted
agricultural wastes. Mushroom germplasm collection was done at 3 different forest reserves
within Kakamega Forest in Western Kenya. Mycelia growth was done through culturing of
collected fruiting bodies on malt extract agar. External and internal mycelia and fruiting body
features were evaluated and used to develop a descriptor for phenetic characterization of the
wood ears. Data obtained from nine randomly selected accessions were used to calculate genetic
similarity and to construct a dendogram. Some mycelia were used to raise spawns, which were
used to inoculate the agricultural wastes. The agricultural wastes were treated to a short
composting procedure, packed in heat resistant polypropylene bags and sterilized before
inoculation. Inoculated substrates were kept in enclosed cabinets to allow mycelia propagation.
They were then transferred to a cultivation room for mushroom growth. The cultivation
experiment was set up as a two factorial Randomized Complete Block Design (RCBD) with
variations in selected mushroom strains, different substrates and supplements. Three wood ear
mushroom strains (Brown, Black, and White), four partially composted substrates (Wheat
straws, Sugarcane bagasse, Grass straws and Corn cobs) and two supplements (Wheat bran and
Rice bran) were used as treatments. Agronomic factors such as mycelia colonization rate,
primordia initiation, yield and fruiting body quality were measured. Data collected were
subjected to Analysis of Variance (ANOV A) to determine differences due to treatment effects.
Mean separation was done using Least Significant Difference (LSD) at pSO.OS. Con-elation
analysis was done to compare some of the variables. The results demonstrated significant genetic
and agronomic variations between the strains. A significant dichotomy separating three (all white
strains) out of the nine accessions at dissimilarity index of 0.318 was observed. The other two
groups (black and brown strains) separated at a narrower dissimilarity index indicating that they
were more closely related. From the cultivation experiment, no significant differences occurred
between the strains on their mycelia growth on malt extract agar. The treatment 40% millet, 40%
sorghum and 20% wheat bran gave the shortest duration of 10 days for spawn production.
Averagely, the black strains gave the best performance on corn cobs supplemented with wheat
bran giving values of3.7, 21, 318 g and 79% for fruiting body quality, number of fruiting bodies,
fresh weight and biological efficiency respectively. The second best production was observed in
wheat straw supplemented with wheat bran. Corn cobs and wheat straw supplemented with
wheat bran were recommended to rural growers. Whereas morphological and productivity traits
significantly separated the strains, further differentiation using molecular markers was
recommended. Further investigation on their growth performance on other agricultural wastes
and in different environmental conditions is necessary.
2010-01-01T00:00:00ZEffects of ungulate Herbivory and tree canopy on Ecosystem processes in Ruma National park, Kenya
https://repository.maseno.ac.ke/handle/123456789/5185
Effects of ungulate Herbivory and tree canopy on Ecosystem processes in Ruma National park, Kenya
NYONGESAH, M.W. John
Herbivores and tree canopies may have significant influences on savanna ecosystem
functioning that are not yet clearly understood. Positive influences of grazers and trees
may be associated with fecal deposition and the ability to fix atmospheric nitrogen
respectively. On the other hand, grazers could negatively influence savanna functioning
through trampling and vegetation removal, while negative influence of trees could be
through shading, which reduces the amount of photosynthetic photon flux density
~ (PPFD) reaching_ the understory. Field studies were carried out in a humid tropical
savanna in Kuma National Park, Kenya to understand how grazing by domestic animals
and the Acacia trees influence ecosystem processes in the herbaceous layer community.
The objectives of the study were; to monitor microclimate and soil moisture during an
annual growth period, to measure the amount of biomass and nitrogen concentration in
the soil and herbaceous layer vegetation during an annual growth period, to measure net
ecosystem CO2 exchange (NEE) and ecosystem respiration (Reco) during the vegetative
period and to determine how trees and grazing influence soil moisture, N distribution,
biomass development and ecosystem CO2 exchange. Soil moisture was measured through
gravimetiic method, plant and soil nutrients were monitored through elementary analysis,
biomass was measured using harvest method while CO2 exchange was determined
through gas chamber method. Measurements were stratified so that locations under the
trees (understory) and in the open, outside the tree canopies were monitored separately to
understand the interactive role of trees. Significant (psO.OOI) differences in peak
aboveground+ biomass at the different locations was recorded with highest peak
aboveground biomass of 902.7±115~ g m-2 Jecorded in non grazed _plots. Trees had
significant Influence on soil moisture content as well as biomass production in both -
grazed and non-grazed plots. Plants in the non grazed plots exhibited significantly
(psO.OOI) higher N content compared to those in the grazed plots and similar trends were
also .observed in the soil N content. Soil moisture, soil N, biomass production and
ecosystem CO2 fluxes exhibited seasonality. Highest N concentration both in the plant
material and in the soil occurred during the rainy period and higher N concentrations
were observed in the tree understory compared to the open locations outside tree
canopies. Significant seasonal changes were observed for NEE, Reco and GPP with Net
ecosystem CO2 exchange increasing during the rainy season up to l Sumol m-2
S-I.
Highest Reco values occurred during the rainy season, with values of 2004 ±O.5 and 23.5
±O.5 umol m-2
S-1 in grazed and non grazed plots respectively. The study showed that
grazing affects soil moisture and soil nutrient content and may significantly influence the
savanna ecosystem functioning. This influence is however, modified by the Acacia trees
through improved soil N content and reduced PPFD in the understory. The observed
trends create a unique production mosaic (understory and open locations) of ecosystem
function and productivity in the humid savanna. Humid tropical savanna ecosystem can
therefore be a significant source and sink of both Nand C with processes that control
their emissions being complex and influenced by a variety of interrelated factors such as
quality and rates of organic matter input to the soil, soil chemical status, soil moisture
status and soil temperature with herbivory acting as modifiers. These findings indicate
that plant dynamics in humid tropical savannas are not a simple function of rainfall
patterns or herbivory, but regulated by interactive effects of rainfall, grazing pressure and
soil nutrients.
2010-01-01T00:00:00ZAnti-bacterial activity of Moringa spp seed.extracts and their water flocculation ability
https://repository.maseno.ac.ke/handle/123456789/5179
Anti-bacterial activity of Moringa spp seed.extracts and their water flocculation ability
ATIENO, Walter . Otieno
Water-borne diseases are some of the main problems in developing countries; about 1.6 million
people compelled to use contaminated water. In many communities in the Winam Division,water clarification/purification methods are often inappropriate because of high cost and low
availability of chemical coagulants, thus they consume water contaminated with disease causing
microorganisms leading to outbreak diseases like typhoid. Natural products from Moringa spp. have
been used as primary coagulants for water treatment. Objectives of the research were to establish
the anti-bacterial activity of M oleifera and M stenopetala and their water clarification ability. 1 kg
powder of shade dried and milled seeds of the M oleifera and M stenopetala were serially soaked
in 2 litres of n-hexane and 2 litres of methanol to extract the active components and placed in a
shaker for 4 hrs. Samples of water collected were processed for water coagulation studies. The nhexane
and methanol filtrates of M oleifera Lam and M stenopetala seed extracts were then
concentrated in a round-bottomed flask using a rotary evaporator under low temperature to obtain
the extracts. 340ml n-hexane extract, 126ml methanol extract of M oleifera and 226ml n-hexane
extract, 67ml methanol extract of M stenopetala were obtained. The anti-bacterial activity of nhexane
and methanol extracts of M oleifera and M stenopetala against Salmonella typha, Vibrio
cholera and Escherichia coli and water clarification ability of their methanol extracts were then
evaluated using randomized complete block design. The results were analyzed using Analysis of
Variance. The results indicated that, n-hexane extract had a higher inhibition on Salmonella typhii
than Vibrio cholera and Escherichia coli and M oleifera was better water clarifier than M
stenopetala. Aluminium sulphate achieved lower turbidity than M oleifera and M stenopetala
extracts. The results showed that M oleifera and M stenopetala had antibacterial and water
clarification ability. The outputs from this research would generate baseline data prerequisite for the
future development of water purification and clarification products.
2010-01-01T00:00:00ZGrowth and Physiological Responses of Bambara Groundnut to Sodium Chloride Salinity
https://repository.maseno.ac.ke/handle/123456789/5141
Growth and Physiological Responses of Bambara Groundnut to Sodium Chloride Salinity
AMBEDE, Jane Gayalwa
Bambara groundnut is one of the most neglected and under-utilized indigenous African legume with potential to alleviate food insecurity, malnutrition and poverty in tropical semi-arid regions of Africa. The crop is drought tolerant, resistant to pests and diseases, produces reasonable yields in low fertile soils and has high nutritional value. Salinity affects plant growth, development and productivity in agricultural soils world wide. It is caused by the accumulation of soluble salts especially sodium and chloride ions in the root zone. This crop may be grown in some semi-arid areas or under irrigation, both of which offer potentially saline conditions. There is limited research on the effect of salinity on growth and physiology of this plant, more so the landraces cultivated in Kenya. The study investigated the effects of NaCI salinity on growth and physiological responses of Bambara groundnut grown in Western Kenya, Kakamega 2 (Kk) and Mumias 2 (Mm).The experiments were laid out in the laboratory and greenhouse at Maseno University botanic garden as a completely randomized design consisting of 5 treatments and 3 replica. Seeds and plants were exposed to NaCI concentrations of electrical conductivity: 0 mm ho em", 6.96 mm ho em", 12.93 mm ho em", 19.89 mm ho cm' and 25.86 mm ho ern" in the growth media. Germination percentage was determined, shoot and root length measured using a meter rule, seedling root and shoot fresh and dry weights measured using an electronic weighing balance, leaf growth, root to shoot biomass ratio, and percentage water content in shoots and roots were determined. Net photosynthesis was measured using an infra-red gas analyzer, chlorophyll fluorescence parameters measured using chlorophyll fluorescent monitoring system, leaf chlorophyll content measured using spectrophotometer and nitrogen content determined using the soil plant analysis device. Data was subjected to analysis of variance using Costat statistical computer package to determine whether the treatment effects were significant or non-significant at 5% level. Least significant difference was used to separate the means. NaCl salinity significantly (P<O.Ol) decreased and delayed germination. Plant growth parameters were significantly (P<O.Ol)reduced by salinity in both landraces however, Mm landrace was more salt tolerant. Salinity significantly (P<O.Ol) reduced chlorophyll and nitrogen content, and net photosynthesis. The Mm landrace had significantly (P<O.05)higher chlorophyll a, band t compared to Kk landrace. Salinity significantly (P<O.05)decreased the FvIFm ratio and electron transport rate inthe two landraces hence decreased plant growth and ultimately productivity, however there were no significant (P>O.05)differences inthe Fv/Fm values for Mm as compared to the control indicating the ability of its PSI! system to function under stressful conditions and thus may contribute to salt tolerance. The Mm landrace seeds seemed to be more salt tolerant at higher salinity (12.93 mm ho em" and 19.89 6.96 mm ho cm') as Kk landrace was at lower salinity (6.96 mm ho ern"). Both landrace seeds may be tried in saline soils with electrical conductivity as indicated.
2012-01-01T00:00:00ZDistribution of the water hyacinth [eichhornia crassipes (mart.) Solms.], its carpet Characteristics, some of its diseases and Pests in the winam gulf of Lake Victoria
https://repository.maseno.ac.ke/handle/123456789/4363
Distribution of the water hyacinth [eichhornia crassipes (mart.) Solms.], its carpet Characteristics, some of its diseases and Pests in the winam gulf of Lake Victoria
OPANDE, George.O
The occurrence of the Water hyacinth (Eichhornia crassipes [Mart.] Solms) in the Winam
gulfhas created numerous negative attributes that make its control an urgent priority. Little
has been reported about its carpet characters and the occurrence of the natural enemies that
areknown to occur with it in other water bodies. Since these natural enemies presented the
most ideal source of viable biocontrol agents, investigations meant to establish their
occurrence and distribution were desirable. Experiments were set up between 1995 and
2000 in selected beaches within the Winam gulf, aimed at establishing the distribution
pattern, origin, carpet characteristics, disease types, disease causative agents and their
suitability for use as biocontrol agents.
Plants meant for the identification exercises were collected from 6 locations, and the
characteristics exhibited by their roots, stems, leaves and inflorescence compared to those
already described as Eichhornia crassipes [Mart.] Solms-Laubach. The entry point of the
water hyacinth was confirmed by conducting an investigation exercise at the Rusinga
. channel. In order to have a better understanding of the seasonal changes in the carpet sizes,
a surveillance program that lasted four years was conducted twice a year (between June
1995 and 1999 November) at Kisumu, Kobala, Homa-bay and Luanda-nyamasaria, The
distribution of water hyacinth growth forms was determined by counting the number of
each growth form that appeared out of 100 plants collected from Kisat bay, Dunga beach,
Luanda Kotieno, Osodo bay, Nyakach bay and Sori bay. Carpet connectivity calculated as
the difference in pressure when weights were added on a mesh wire measuring 0.434 m2
until the carpet submerged and the pressure on the same carpet that was required to
submerge it after a complete disconnection. The standing population density was
determined by counting the number of plants found within quadrants measuring 1m2
located at Dunga beach, Kisumu pier, Kusa, Kobala and Kendu bay, while the biomass
density was determined when oven dried plant materials collected from quadrants
xv
l
measuring 1 m2 were weighed. The plant mass and rhizome length measurements were
correlated, while the population density was correlated to biomass density within the same
carpet. Water hyacinth plants showing disease symptoms whose causative agents were
unknown were collected from the Winam gulf and brought to the Labor,atory for isolation
purposes. Potato Dextrose Agar (PDA) cultures of each pathogen were prepared and the
disease causative organism isolated. Pathogenicity trials were conducted in accordance to
Koch's postulates.
When the counts for growth forms were complete, the larger growth form occurred 45.0%
while the medium and small occurred at 34% and 21%. There was no correlation between
therhizome measurements and the fresh weight, but the correlation between the population
density and biomass was highly significant with r2 = 0.9202. Six genera of filamentous
fungi together with an unidentified number of bacterial forms found occurring with the
water hyacinth in the Winam gulf The isolated species include; Myrothecium roridium,
Acremonium zonatum, Rhizoctonia solani, Fusarium sp., Cercospora sp. and Alternaria sp.
The results obtained from this study have confirmed the occurrence of more than six water
hyacinth phytopathogens that can be developed into mycoherbicides. They have shown that
the water hyacinth distribution in the Winam gulf is seasonal, adopts secluded bays and
mostly exhibit the large growth form. It is now clear that carpets measuring 0.434m2 in size
that have a connectivity of288.4 Pa (pascal) are able to support a weight of 12.6 kg. only,
with any additional weight causing them to submerge. The distribution of plant mass in the
Winam gulf is normal except in locations that are subjected to external factors.
This study has provided a reference point from which any future biocontrol exercise or any
scientific project designing a harvester machine for use in the Winam gulf can take off.
Thesis (PhD)
2002-01-01T00:00:00ZResponses of Humid Savanna Vegetation to the Interaction of Livestock Grazing and Rainfall Variability In Lambwe Valley, Kenya
https://repository.maseno.ac.ke/handle/123456789/4004
Responses of Humid Savanna Vegetation to the Interaction of Livestock Grazing and Rainfall Variability In Lambwe Valley, Kenya
OTIENO , Joseph Ondier
Tsetse fly control in Lambwe valley has made the region habitable and opened it up for human settlement. The region has, therefore, experienced a steady increase in human population growth. Since most of the households in Lambwe keep livestock as a source of livelihood, the increased human population has consequently resulted in increased livestock numbers and grazing pressure. At the same time, the region is experiencing changes in rainfall patterns which are projected through increased rainfall during wet seasons and prolonged dry periods. Increased livestock grazing and changing rainfall regimes in Lambwe valley Homabay County, Kenya is threatening the existence of plant life forms in Lambwe, but has rarely been studied. The increased grazing and rainfall variability are occurring simultaneously and their implication on the savanna vegetation is not known. Holistic studies that monitor vegetation responses in this valuable ecosystem, are limited. This study analysed the responses of the herbaceous and tree layers to livestock grazing and rainfall variability. The objectives of the study were; i. To determine the interactive effect of livestock grazing and rainfall variability on CO2 exchange, species diversity, composition and palatability of the herbaceous vegetation, ii. To determine the effect of livestock grazing and rainfall variability on CO2 exchange of the tree canopy, iii. To compare productivity responses of tree and herbaceous vegetation under livestock grazing and rainfall variability. Within the herbaceous layer, rain-out shelters were erected above canopy of herbaceous vegetation that was either grazed by livestock or fenced to exclude livestock. The shelters, each measuring 9 m by 6 m were replicated three times on both the grazed and fenced plots. On each of the plots, ambient rainfall was reduced or increased by 50 % using transparent plastic sheets. Within the tree vegetation, three replicates of grazed and fenced plots, each measuring 70 m by 50 m were demarcated for measurements. There was no rainfall manipulation on the tree plots. Measurements included microclimate, soil moisture content, soil bulk density, CO2 fluxes, biomass, species diversity and palatability in the herbaceous layer and sap flow measurements in the trees. Herbaceous Gross Primary Productivity (GPP) was calculated from Net Ecosystem Exchange (NEE) and Ecosystem Respiration (Reco) measured directly with the chambers. Daily GPP for both trees and herbaceous layer was determined using PIXGRO model. Livestock grazing significantly (P ≤ 0.05) reduced herbaceous CO2 exchange but had no influence on tree productivity. The interaction of grazing and rainfall reduction significantly (P ≤ 0.05) reduced GPP, NEE and Reco by 22.5 %, 33% and 39% respectively. The interaction of grazing and rainfall increment significantly increased GPP and NEE by 47 % and 54.8 % respectively, but had no influence on Reco. The interaction of grazing and rainfall reduction significantly (P ≤ 0.05) reduced herbaceous diversity whereas the interaction of grazing and rainfall increment had no significant (P > 0.05) impact on herbaceous diversity. Rainfall manipulation had no significant (P > 0.05) impact on dominance of herbaceous vegetation in either fenced or grazed plots. Herbaceous daily maximum GPP exhibited higher seasonal fluctuations than the tree layer. The overall mean maximum daily ecosystem productivity for the study site was 10.73 ± 1.7 g C m -2 d-1 and 13.75 ± 1.62 g Cm-2 d-1 in the grazed and fenced plots respectively. The herbaceous vegetation, which was the dominant vegetation life form in the valley, contributed about 60 % to the overall mean maximum daily ecosystem productivity. The CO2 fluxes, diversity and composition of the herbaceous layer in the grazed savanna responded disproportionately to the rainfall manipulation, suggesting that grazing and rainfall are not the sole factors driving herbaceous CO2 exchange in this ecosystem. The differential response of trees and herbaceous GPP to livestock grazing was linked to the variations in rooting patterns of the two vegetation types. The significant contribution of the herbaceous layer to the overall ecosystem productivity was connected to higher herbaceous vegetation cover of about 80 %. The results of this study have a significant implication for the theoretical understanding of the tree-herbaceous responses to livestock grazing and rainfall variability. Further, this study provides empirical data that can be used for refining and parameterizing vegetation models that predict future savanna ecosystem responses to livestock grazing and rainfall variability
2021-01-01T00:00:00ZCorrelations between schistosoma mansoni-specific immunoglobulins (igg1, igg2, igg3, igm), infection intensity and age among school pupils in Asembo area, western Kenya.
https://repository.maseno.ac.ke/handle/123456789/3660
Correlations between schistosoma mansoni-specific immunoglobulins (igg1, igg2, igg3, igm), infection intensity and age among school pupils in Asembo area, western Kenya.
AJWANG, Joseph Ombidi’
ABSTRACT
Schistosoma mansoni is a blood parasite that is common among school going pupils living near water bodies. It causes a disease known as schistosomiasis or bilhaziasis. Infected pupils stand higher risks of developing anaemia, absenteeism from school, retarded physical and mental growth and development, hence poor academic achievement. Human hosts respond to the infection by producing various immunoglobulins like IgA, IgD, IgE, IgG1, IgG2, IgG3, IgG4 and IgM. Some of these immunoglobulins like IgG1, IgG3 and IgE confer protective immunity to the host against the infection, while others like IgG2, IgG4 and IgM lead to susceptibility of the host to the infection. Although studies have been conducted in Asembo area indicating a prevalence rate of S. mansoni infection at 35-80% among school children, infection intensity of the parasite, levels of protective and susceptibility immunoglobulins, and correlations between these antibodies in relation to the infection intensity and age among the infected children have not been established. This study sought to investigate the infection intensity, levels of IgG1, IgG2,, IgG3 and IgM immunoglobulins, and how these antibodies correlate with intensity of infection and age among school children suffering from S. mansoni in Asembo, which is an endemic area for the infection. The study followed a cross-sectional design and involved use of 350 stool and venous blood samples obtained from S. mansoni-infected children aged between 5-20 years, attending primary and secondary schools in Asembo area. The study area has a total of 31,293 school-going children. The participants were recruited using simple random sampling technique. The stool samples were used for determination of infection intensities by means of Kato Katz technique. The blood samples were used to obtain plasma for determination of immunoglobulin levels by means of indirect Enzyme Linked Immunosorbent Assay (ELISA) method, using soluble worm antigen preparations (SWAP) and soluble egg antigens (SEA) of the parasite. Multivariate analysis of variance (ANOVA) was conducted to determine if mean levels of immunoglobulins and infection intensities were significantly different between the age groups. Tukey’s Honest Significant Difference test was used to obtain the least significant differences in the levels of the immunoglobulins and infection intensities. Spearman’s Rank Correlation Coefficient was used to determine the correlations between concentrations of the IgG1, IgG2, IgG3 and IgM immunoglobulins versus infection intensity and age of the infected school pupils. Regression analysis was done to assess the strength of associations between levels of the immunoglobulins, infection intensity and age. Levels of the immunoglobulins were dependent variables while intensity of infection and age were independent variables. The levels of anti-SWAP IgG1, IgG3 and anti-SEA IgG1 peaked at the age bracket of 17-20 years. The levels of anti-SWAP IgG2, IgM and anti-SEA IgM were highest at the age bracket of 5-8 years. The anti-SEA IgG3 levels peaked at the age bracket of 9-12 years. Intensity of infection was highest at 184.06 eggs per gram at the age bracket of 13-16 years. Positive correlations existed between anti-SWAP IgG1 and infection intensity (
= 0.321, p=0.001), anti-SWAP IgG2 and infection intensity (
=0.187, p=0.001), anti-SEA IgG1 and intensity of infection (
=0.168, p=0.002) and anti-SEA IgG3 and infection intensity (
=0.155, p=0.005). Negative correlations were found between anti-SWAP IgM and infection intensity (
=0.115, p=0.039). No correlations existed between anti-SWAP IgG3 and infection intensity (
=0.011, p=0.838) and anti-SEA IgM and infection intensity (
=0.097, p=0.082). Positive correlations were established between anti-SWAP IgG1 and age (
=0.472, p=0.001), anti-SWAP IgG3 and age (
=0.223, p=0.001), and anti-SEA IgG1 and age (
=0.286, p=0.001). There were negative correlations between anti-SWAP IgG2 and age (
=-0.476, p=0.001), anti-SWAP IgM and age (
=-0.436, p=0.001) and anti-SEA IgM and age (
=0.315, p=0.001). There were no correlations between anti-SEA IgG3 and age (
=0.073, p=0.193). The
and P values were considered to be statistically significant at
>0.1 or
>-0.1, and P<0.05 respectively. It was concluded that as the school children grow older, there is an increase in levels of protective immunoglobulins like IgG1 and IgG3 while on the other hand there is a decrease in levels of blocking immunoglobulins like IgG2 and IgM. The findings of this study are expected to enhance the understanding of the immunological relationship between the human host and S. mansoni parasite during the infection, hence provide research scientists with additional knowledge aimed at developing a vaccine against schistosomiasis. The study recommends investigations into the correlations between total IgG levels versus infection intensity and age of infected school pupils, and use of more sensitive protocols for assaying anti-SEA IgG2 levels.
2017-01-01T00:00:00Z