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Biocompost has been identified as an alternative to chemical fertilizers that increased soil microbial population and soil enzyme activities in sustainable farming. The objective of this field study was to evaluate the effect of three halophytic composts in combination with farmyard manure and phosphate solubilising bacteria (Bacillus megaterium) on soil microflora and enzyme activities. The results show that among nine treatments given, the application of Suaeda compost in combination with farmyard manure and phosphate solubilising bacteria (T 9 ) significantly increased the soil microflora such as bacteria, fungi and actinomycetes and soil enzyme activities such as dehydrogenases, alkaline phosphatase, cellulase and urease in soil cultivated with Arachis hypogaea.

Field studies were conducted to determine the role of defense mechanism in various parameters associated with plant protection subjected to UV-B radiation in Phaseolus trilobus Ait. commonly used as green manure and fodder. Spectrophotometric analysis showed that UV-B radiation decreases the chlorophyll content and increased the amount of UV-B absorbing compounds such as anthocyanins and flavonoids. Other UV-induced alterations included reduction in fresh weight and leaf area. However, wrinkling of leaves and increased leaf thickness was observed in UV-B treated seedlings. The antioxidant enzymes were unaffected and showed enhanced activity, except catalase in UV-B treated seedlings. These results suggest that, in general, UV-B radiation caused oxidative damage. However, plants have evolved complex mechanisms to scavenge the active oxygen species and thereby protect the cellular membrane, pigment and organelle.Key Words: Anthocyanin, catalase, chlorophyll, phenol, superoxide dismutase, UV-B radiation RÉSUMÉDes études sur le terrain ont été conduites pour déterminer le rôle du mécanisme de défense dans divers paramètres liés à la protection des plantes soumises au rayonnement UV-B dans le Phaselus trilobus Ait. communement utilisé comme engrais verts et fourrage. L'analyse spectrophotométrique a prouvé que le rayonnement UV-B diminue le contenu en chlorophylle et augmente la quantité de composés absorbant l'UV-B tels que des anthocyanines et des flavonoïdes. D'autres altérations d'UV-induits ont inclus la réduction de poids à l'état frais ainsi que de la surface foliaire. Cependant, on a observé des feuilles ridées et un accroissement en épaisseur de feuilles des plantules traitées par UV-B. Les enzymes antioxydantes n'étaient pas affectées et ont montré une augmentation de leur activité, à l'exception de la catalase dans les plantules traitées au UV-B. Ces résultats suggèrent que, en général, le rayonnement UV-B cause le dommage oxydative. Cependant, les plantes ont développé des mécanismes complexes pour se débarrasser des espèces d'oxygène actif et ainsi protéger la membrane cellulaire, le pigment et organelle.

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BALAKRISHNAN V., VENKATESAN K., RAVINDRAN K.C., KULANDAIVELU G. (2005): Protective mechanism in UV-B treated Crotalaria juncea L. seedlings. Plant Protect. Sci., 41: 115-120.There is concern that some anthropogenic atmospheric pollutants may result in a global reduction of stratospheric ozone. This would undoubtedly increase the level of ultraviolet radiation reaching the surface of the earth, which might have important biological consequences. The antioxidant defence system of a plant consists of a variety of antioxidant molecules and enzymes. The role of antioxidant enzyme activities in Crotalaria juncea under control without UV-B treatment and ultraviolet-B supplemental radiation (UV-B) was investigated. UV-B treatment for 6 h for 4 days resulted in severe inhibition in catalase activity. On the other hand, the activities of peroxidase, polyphenol oxidase, superoxide dismutase and phenylalanine ammonialyase increased after the UV-B treatment when compared to control seedlings. These increases could be an adaptive mechanism to minimise the effects of UV-B radiation. Keywords: Crotalaria juncea L.; UV-B radiation; antioxidant; catalaseAbbreviations: UV-B -Ultraviolet-B; O 2 -,-Oxyradical; PVP -Polyvinyl pyrolidone 116Vol. 41, decreased stem length, leaf area and plant height in cucumber, sunflower, soybean and loblolly pine (TEVINI & TERAMURA 1989). Reduction in biomass accumulation resulting from increased UV-B radiation was observed in wheat, barley, soybean, tomato, cucumber and lettuce (KRUPA & KICKERT 1989). However, defence mechanisms such as foliar symptoms like curling of leaves and shiny wax coating (NEDUN-CHEZHIAN & KULANDAIVELU 1996), synthesis of phenolic substances such as anthocyanin and flavonoids (RAVINDRAN et al. 2001) and synthesis of antioxidant enzymes like peroxidase, polyphenol oxidase and superoxide dismutase (RAO et al. 1996) have been observed in UV-B treated Arabidopsis thaliana seedlings. Many plants possess very efficient scavenging systems for reactive oxygen that protects them from destructive oxidative reactions (ARORA et al. 2002). UV-B radiation increases the production of reactive oxygen species (H 2 O 2 , O 2 -, OH − ). These oxygen species are extremely reactive and have a cytotoxic nature (BOWLER et al. 1992). Plants have evolved protective mechanisms to keep these deleterious reactions to a minimum. Antioxidative enzymatic defence includes catalase, peroxidase and superoxide dismutase. Polyphenol oxidase and phenylalanine ammonialyase also participate in protection via phenolic compounds. These enzymes can mitigate the UV-induced damage by protecting the photosynthetic pathway and cellular components. The present study was conducted to determine the role of antioxidant defence mechanism in UV-B treated seedlings of Crotalaria juncea L., a plant widely cultivated in South India as green manure. MATERIALS AND METHODS Plants.Pre-soaked seeds of Crotalaria juncea were germinated in the dark for 2 days and then transferred to indirect daylight in the laboratory. Af...

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As an alternative to chemical fertilizer, biocompost has been identified to increase the yield characteristics of Arachis hypogaea Linn. for sustainable agriculture. The objective of this field study was to evaluate the effect of three different types of halophytic composts in combination with farmyard manure (FYM) and phosphate solubilising bacteria (Bacillus megaterium) on yield characteristics such as number of pods per plant, fresh pod weight, dry pod weight , pod yield, haulm yield, shelling percentage and hundred kernel weight. From the results it was is observed that among nine treatments given, the application of Suaeda compost in combination with FYM and phosphate solubilising bacteria (T 9) significantly increased the yield characteristics in Arachis hypogaea cultivated in coastal saline soil. The resulting halophytic compost improves the quality and fertility of the saline soil.

Sandal logs after removal from the natural stands are stored in depots pending sale. During this storage they are heaped in the open, exposed to the elements; consequently the logs are attacked hy a numher of hasidiotnycetous fungi; mainly the attack is on sapwood, rarely heartwood is also affected. In view of the value of sandalwood, it is necessary to protect the logs to prevent deterioration of both sapwood and heartwood.Sandalwood because of its intrinsic value due to the oil obtained from heartwood, is stored in special depots with security measures to ensure safe keeping from theft. Unfortunately no attention is paid to prevent deterioration of the wood by borers and decay fungi. These cause damage to the sapwood and heartwood of sandal to varying extents.Before the billets are stored in lockers at the depots, the dead trees are left in the forest or at best, the logs are piled upon the damp soil littered with decaying plant remains, exposed to temperature and humidity variations, for several months. This provides the ideal conditions for attack of decay organisms like fungi, bacteria, slime molds and insects. The logs are thence removed to sandal depots and piled up again in the open or under shade before being auctioned. The decay fungi require a balance between air and moisture to cause deterioration and this balance is ideally provided by the existing storage practices of sandalwood.The investigations were undertaken to find out the extent of damage, if any, caused by the decay fungi and to suggest prophylactic measures to prevent deterioration by decay during storage. Materials and methodsFungi attacking logs of sandalwood were collected from the natural forests before transportation to the depot; sporophores were also collected from the logs stored in the sandal depots of Sathyamangalam and Salem depots at Tamil Nadu, Cultures were obtained by placing hits of affected wood or sporophores in malt agar medium in petri dishes, later transferred to slants and incubated at room temperature, varying from 28°C to 32°C. Decay tests hy inoculating the fungi into sterile wood blocks for assessing the extent and rapidity of decay are also attempted. The results of these studies would be communicated later.Fungi associated with sandal logs 1. Hexagonia discopoda Pat. et Har. Fungi: Basidiomycetes, Aphyllophorales. This causes brown cubical rot, is a common cause of decay of timber exposed to weather, but can occur as a wound parasite of weak trees, growing in unfavourable localities; dark brown stains U.S.