Suchit A. John

Optimization of phytohormone combinations for in vitro callogenesis inLavatera cashmeriana : An endemic medicinal plant of Kashmir

The state of Jammu and Kashmir is bestowed with diverse variety of plant species especially medicinally important plants due to wide variations in its topography and microclimatic conditions. Lavatera cashmeriana Camb. (Malvaceae), which is endemic and endangered to Kashmir valley, has great medicinal importance. Its parts are being used to treat sore throat and common cold. In the present study various phytohormones auxins and cyotkinins either alone or in combination were used for the in vitro callogenesis of medicinally important herb of Kashmir. The excellent results from the seeds of Lavatera cashmeriana were observed on the Murashaige and Skoog medium supplemented with 2,4D and BAP. In future a fine tune and refinement of phytohormones are required in terms of the concentration for the organogenesis of medicinally important plant.

In Vitro Screening of Plant Growth Promoting Rhizobacteria to Control Bacterial Wilt ( Ralstonia solanacearum ) of Tomato ( Lycopersicon esculentum )

Ralstonia solanacearum is the causative agent of bacterial wilt that causes considerable damages in the yield of various crop plants. The intent of the study was to evaluate potential of bacterial antagonists to suppress bacterial wilt disease development and evaluate the role of the strains as plant growth-promoting rhizobacteria (PGPR) in tomato. One hundred rhizosphere bacterial isolates were screened against virulent strain of Ralstonia solanacearum . After in vitro screening 10 antagonistic strains designated PR3, PR17, PR26, 1NAB15, 1NAB20, 3NAA1, 3NAA2, 2CBA2, 2CBA4, 2CBA18 showed antagonistic effect by producing inhibition zone supressing the growth of R. Solanacearum . The isolate PR3 showed the highest inhibition zone measuring 33.3mm whereas 1NAB15 showed the lowest zone measuring 10mm. The present study, therefore, suggests that the use of PGPR isolates which showed the antagonistic activity can be used as inoculants/ bioantagonists might be beneficial for the control of bacterial wilt of tomato in field studies.

Effect of Exogenous Application of Salicylic Acid on Some Morphological Parameters in Salt Stressed Tomato Varieties

Salt stress is a major environmental constraint limiting plant productivity. Tomato ( Lycopersicum esculentum) is one of the commodity vegetable that has recently been added to the list of the worlds major food crops and is considered as one of the most popular vegetable. An experiment was conducted to study the effect of salicylic acid (SA) on tomato varieties grown in different levels of salt stress. Salicylic acid (SA) is a plant growth promoting compound relatively inexpensive and enhances growth and yield of crops under saline conditions. The effect of exogenous salicylic acid (25μM) application of with four NaCl concentrations (50mM,100mM, 150mM and 200mM) stressed tomato varieties was investigated. Results on some morphological parameters as plant-height and number of leaves revealed that, salt stressreduced plant-height and number of leaves. While, exogenous application of salicylic acid promoted plant-height and number of leaves and counteracted the salt stress-induced inhibition of plant-height and number of leaves.

Evaluation of exogenous application of 24-epibrassinolide and silicon on mophological characters of salt stressed wheat varieties

Wheat is a major cereal crop in many parts of the world and it is commonly known as king of cereals. Brassinosteroids (BRs) are growth-promoting natural products found at low levels in pollen, seeds, and young vegetative tissues throughout the plant kingdom. An experiment was conducted to evaluate the effect of different combinations of Silicon (Si) and 24epibrassinolide (EBL) on wheat varieties grown under 100 mM salt stress. The result showed that shoot length of plant increased with the application of EBL and Silicon and it was increased the maximum in salt tolerant varieties in comparison to non-tolerant. Whilst, reduction was observed in root length along with the increasing concentration of EBL. The effect of different combinations of silicon and 24-epibrassinolidealso increased the germination percentage (%) in tolerant and non-tolerant wheat varieties.

Fluctuation of Photosynthetic Pigment of Water-Stressed Cowpea Vigna unguiculata (L.) Walp. Varieties

Photosynthetic pigments are responsible for conversion of light energy into a form of chemical energy in the plants. The most important pigment in the light harvesting machinery of the plant is chlorophyll and Carotenoids play an important role in photo-protection of chlorophyll molecules. Cowpea responds to survive under water-deficit conditions via a series of physiological, cellular and molecular processes culminating in stress tolerance. Most cowpea is produced in arid and semi-arid zone. This experiment was conducted in the research field of Department of Biological Sciences, Sam Higginbottom Institute of Agricultural Technology and Sciences, Allahabad. To study the chlorophyll a, chlorophyll b and carotenoid content of three cowpea varieties (UU-0, VU-89 and KK-6) subjected to the different level of watering (daily watering, 2 days interval, 4 days interval and 6 days interval of watering). The experimental materials were arranged inRandomize Complete BlockDesign. The results indicate that the all photosynthetic pigments such as chlorophyll a, chlorophyll b and carotenoid content maximum in daily watering whereas at 6 days interval of watering observed minimum.