Competition of the active roots of Cassia siamea Lam. and Zea mays L.(cv.Katumani Composite B) in an alley cropping trial in semi arid Kenya

A study on root competition in alley cropping was carried out in an agroforestry system, involving Cassia siamea Lam. and maize ( Zea mays L. cv. Katumani composite B). The existence and intensity of root competition in the top soil as manifested by the distribution of the active roots of cassia and maize, in space and time, was assessed. The root length density of maize was far greater than that of cassia in the upper 10 cm, implying that cassia was not competing with maize for water and/or nutrients at that depth. However, at maize crop tasselling and grain filling stages there was a marked overlap of roots of the two plants at lower depths (20—50 cm). This varied with distance from the cassia hedge in a way that there was a tendency for highest overlap near middle maize rows. This partly explained observed yield differences. Therefore cassia may not be a suitable choice for alley cropping with maize under semi-arid conditions on non-sloping land, unless most of its active roots can be properly managed to absorb resources below the feeding rhizosphere of the active maize roots.     

真,假草本咖啡种子的鉴别

在对草本咖啡（Ｃａｓｓｉａｓｏｐｎｅｒａｉｉｎｎ）、望江南（ＣａｓｓｉｓｏｃｃｉｄｅｎｔａｌｉｏＬ．）和决明（ＣａｓｓｉａｔｏｒａＬ．）种子的大小、颜色、形态进行了观察、研究，并对其形态特征进行了解剖学的分析后，提出了鉴别３种种子的方法。     

Competition of the active roots of Cassia siamea Lam. and Zea mays L.(cv.Katumani Composite B) in an alley cropping trial in semi arid Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｅｏｆｔｈｅｍａｊｏｒｄｒａｗｂａｃｋｓｏｆａｌｌｅｙｃｒｏｐｐｉｎｇｓｙｓｔｅｍｓｉｎｓｅｍｉａｒｉｄｌｏｗｆｅｒｔｉｌｉｔｙｃｏｎｄｉｔｉｏｎｓｉｓｃｏｍｐｅｔｉｔｉｏｎｆｏｒａｖａｉｌａｂｌｅｗａｔｅｒａｎｄｎｕｔｒｉｅｎｔｓ．Ｃｏｍｐｅｔｉｔｉｏｎｉｓｔｏｂｅｅｘｐｅｃｔｅｄｉｆｔｈｅｔｒｅｅａｎｄｔｈｅｃｒｏｐｈａｖｅｏｖｅｒｌａｐｐｉｎｇａｃｔｉｖｅｒｏｏｔｓｙｓｔｅｍｓｉｎｓｐａｃｅａｎｄｔｉｍｅ．Ａｋｎｏｗｌｅｄｇｅｏｆｔｈｅｓｐａｔｉａｌｄｉｓｔｒ…     

Equilibrium,kinetics and thermodynamics of hexavalent chromium biosorption on pristine and zinc chloride activated Senna siamea seed pods

Hexavalent chromium contamination in water is an issue of huge concern due to its use at a high scale, toxicity and non-biodegradability. Biosorption is a cost effective and unconventional strategy for the elimination of Cr(VI). Here, a novel biosorbent Senna siamea seed pod biomass and its chemically activated form have been investigated for the elimination of hexavalent chromium from aqueous solution. The biosorbent was characterized by using BET, FTIR, FESEM-EDX and TGA techniques. Parameters controlling the biosorption process were optimized as pH 2.0, temperature 30°C, initial Cr(VI) concentration 500?mg/L, biosorbent dose 0.5?g/L. Optimized contact time was 210 and 180 min for pristine biomass and activated carbon, respectively. Langmuir isotherm correlated well with experimental data revealing that the biosorption occurred in monolayer pattern. Maximum biosorption capacity calculated by Langmuir biosorption isotherm was 119.18 and 139.86?mg/g for S. siamea pristine biomass and activated carbon, respectively. Pseudo-second order kinetic model correlated well with experimental data. Thermodynamic studies suggested that the biosorption process occurs in a non-spontaneous, stable and endothermic manner. These interesting findings on Cr(VI) biosorption by S. siamea seed pod biomass and S. siamea zinc chloride activated carbon vouches for its potential application as an unconventional biosorbent.     

Flocculants—an Ecofriendly Approach

Although water-soluble synthetic polymers find wide applications as flocculants, the potential problem associated with their use is lack of biodegradability and high cost. Polysaccharides owing to their distinctive features like ability to undergo different chemical reactions, biodegradability and sustainability inspire hope to obtain effective, economical viable and safe substitute of the synthetic flocculants. In this regard, chemical modification of Cassia tora and guar gum was carried out through different substitution and grafting reactions. The modified products were tested against kaolin under laboratory conditions vis-a-vis polyacrylamide based synthetic flocculant.     

Understanding yields in alley cropping maize (Zea mays L.) and Cassia siamea Lam. under semi-arid conditions in Machakos, eastern Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｌｙａｂｏｕｔ 2 0 %ｏｆＫｅｎｙａ’ｓｔｏｔａｌｌａｎｄａｒｅａｈａｓｈｉｇｈｐｏｔｅｎｔｉａｌｆｏｒａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｏｎ ,ｔｈｅｒｅｓｔｂｅｉｎｇａｒｉｄｏｒｓｅｍｉ ａｒｉｄ .ＴｈｅａｎｎｕａｌｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｉｎＫｅｎｙａｏｆｃｌｏｓｅｔｏ 4 %ｉｓｏｎｅｏｆｔｈｅｈｉｇｈｅｓｔｉｎｔｈｅｗｏｒｌｄ (ｅ .ｇ .ＵｎｉｔｅｄＮａｔｉｏｎｓＤｅｖｅｌｏｐｍｅｎｔＰｒｏｇｒａｍｍｅ ,1990 ) .Ｔｈｉｓｓｉｔｕａｔｉｏｎｈａｓｌ…     

Phenotypic nutrient up-take differences in an alley cropping system in semi-arid Machakos, Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅＦｉｆｔｈＦｒａｍｅｗｏｒｋＰｒｏｇｒａｍｍｅｏｆｔｈｅＥｕｒｏｐｅａｎＣｏｍｍｉｓｓｉｏｎ(ＥＣ,1999),ｕｎｄｅｒ“ｔｏｏｌｓｆｏｒｓｕｓｔａｉｎａｂｌｅｄｅｖｅｌｏｐｍｅｎｔ”,ｔｈｅｒｅｗａｓｒｅｃｅｎｔｌｙａｓｐｅｃｉａｌｃａｌｌｆｏｒｐｒｏｐｏｓａｌｓｆｏｒ“Ｔｅｃｈｎｏｌｏｇｉｅｓｆｏｒｓｕｓｔａｉｎａｂｌｅｐｌａｎｔａｎｄａｎｉｍａｌｐｒｏｄｕｃｔｉｏｎ:ｂｕｉｌｄｉｎｇｂｌｏｃｋｓｆｏｒｉｍｐｒｏｖｅｍｅｎｔ(ｆｏｒｓｍａｌｌｓｃａｌｅｏｒｅｎｖｉｒ…     

In vitro assessment of natural plant extracts Withania somnifera,Cassia fistula,Saraca asoca,and Eucalyptus tereticornis using primary chicken embryo fibroblast cell culture treated with urea or mercuric chloride (II)

The present investigation examined the detoxifying potential of methanolic herbal extracts, namely the leaf and bark extract of Eucalyptus tereticornis, bark extract of Saraca asoca, Cassia fistula and Withania somnifera in vitro using primary chicken embryo fibroblast (CEF) cells against damaging effects of urea and mercuric chloride (HgCl) (II). The influence of 20?mM urea and 10?µM?HgCl (II) was determined on cell viability or proliferation of cells after treatment with plant extracts. Higher survival rate of primary CEF cells treated with higher concentrations of plant extracts was observed due to their protective ability against urea and HgCl (II). Cassia fistula bark extract (10?mg?mL^?1) was found to be most effective against 20?mM urea as it protects 90% of CEF cells whereas W. somnifera protects 86% of the cells within 24?h. After treating cells with10?µM HgCl, W. somnifera and E. tereticornis leaf extracts were found to be more effective among all other extracts as they protect approximately 86% and 70% of CEF cells, respectively, within 24?h. These results indicate that C. fistula and W. somnifera has the highest potential amongst all the five plant extracts for protecting CEF cells against damaging effects of urea and HgCl (II), respectively.     

Evaluation of air pollution phytotoxicity downwind of a phosphate fertilizer factory in India

The effects of air pollution on plants downwind of a fertilizer factory at Udaipur, India, were studied using three woody perennials. Seedlings of these species including a shrub (Carissa carandas L.), a leguminous avenue tree (Cassia fistula L.) and a fruit tree (Psidium guajava L.) were grown in earthen pots at different study sites receiving varying levels of air pollution input. Changes in plant growth, morphological characteristics, photosynthetic pigment, ascorbic acid, N and S contents and in dry matter allocation were considered in relation to the status of ambient air quality. Observations with these parameters have indicated that the ambient air around the factory contained pollutants at phytotoxic levels. Plant height, basal diameter, conopy area, leaf area and chlorophyll, ascorbic acid and foliar-N concentrations decreased with increasing pollution load. However, foliar-S increased slightly at polluted sites. Air pollution load around the factory have also altered the biomass allocation. Root:shoot ratios increased in C. fistula and P. guajava at polluted sites. In contrast, for C. carandas the above ground parts, where foliage assumed predominance showed precedence over the root growth. This species responded characteristically to air pollution stress by allocating more of its photosynthate towards leaf production and shoot growth.