World Journal of
Pharmaceutical and Life Sciences

INFLUENCES OF WATER STRESS ON PLANT PHOTOSYNTHETIC, GROWTH AND LEAF YIELD OF DIFFERENT MAULBERRY VARIETIES

N. Obulapathi, P. Sivakumari, P. Sudhakar* and S. Thimma Naik

ABSTRACT

Photosynthesis plays a prime role in carbohydrate metabolism and influenced by environmental stress conditions. Water stress is one of the environmental stress factors, which alters several regulatory mechanisms and consequently leads to yield loss in crop plants. With the above background information, selected six mulberry (Morus sp.) genotypes namely V1, M5, G4, G2, RC1 and RC2 and conducted experiments under natural photoperiod conditions in potted plants under normal and water stress conditions. During the experimentation physiological parameters such as photosynthetic rate, stomatal conductance, transpiration rates and relative water content and plant growth and yield parameters under control and stressed plants was recorded. Results indicated that water stress conditions have significantly influenced the altering of all photosynthetic and plant growth and yield parameters in water stressed conditions compared to watered conditions (normal). Photosynthetic rate was significantly reduced in all the varieties in the order viz. V1 (17.6 ? mol CO2/m-2s-1), M5 (9.84), G4 (7.77), G2 (8.79), RC1 (7.40) and RC2 (12.9) as compared to Controls of V1 (22.2), M5 (11.4), G4 (10.4), G2 (13.4), RC1 (9.79) and RC2 (14.81? mol CO2/m-2s-1), respectively. Similar trend was noticed in case of stomatal conductance, transpiration rate, chlorophyll content, relative water content and other mulberry plant growth and yield parameters of all the varieties. However it was reverse in case of Transpiration rate. It was recorded increased levels in stress conditions compared to normal watering in all the varieties in the order V1 (5.54-5.27? mol CO2/m-2s-1) followed by M5 (5.32-5.33), RC2 (4.12-4.84), G4 (3.12-3.15), G2 (2.37-5.57) and RC1 with 2.24 to 2.48? mol CO2/m-2s-1, respectively. Water stress conditions also affected the mulberry plant growth and yield parameters in all the varieties in the order as mentioned above. From the study it can be inferred that water stress conditions not only hamper the physiological parameters but also severely affects the plant growth and yield parameters and inferring that this information can be used in screening the mulberry genotypes for water stress tolerance.

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