Ecology, Environment and Conservation Paper

EFFECTS OF CHEMICALS ON WATER STRESS ALLEVIATION IN. BLACK PEPPER (PIPER NIGRUM L.) ROOTED CUTTINGS

M. Alagupalamuthirsolai, Renuka Suresh, V. Srinivasan, C.K. Thankamani and R. Gobu

Abstract

In the era of climate change, water stress is a major limiting factor in black pepper, as it is highly sensitive to water deficit stress especially during summer, which can lead to greater production losses. Therefore, strategies aimed at enhancing water deficit tolerance in black pepper is crucial to stabilize production and productivity. Water deficit alleviating chemicals improves tolerance in plants; however, its mechanism in black pepper rooted cuttings under water deficit stress is yet to be explored. Therefore, we conducted a two pot culture experiment during March and April, 2022 using the variety Panniyur-1 to investigate the effects of alleviating chemicals with six treatments viz., T1 - Well-Watered (WW), T2 - Water stress (WS), T3 -WS + foliar spray chitosan (25 ppm), T4 - WS + foliar spray of lime (1%), T5 – foliar spray of Potassium silicate (0.5%) + Calcium chloride (0.5%), T6 - WS + foliar spray of Melatonin (50 μM) on the recovery per cent, leaf. relative water content, photosynthetic gas exchange, chlorophyll fluorescence, canopy temperature and proline accumulation in black pepper leaves under water deficit stress. In general, the application of exogenous stress alleviating chemicals significantly relieved the inhibitory effects of water deficit stress on leaves. Especially, the melatonin enhanced tolerance attributed to improved leaf water content, photosynthetic activity, reduced canopy temperature, and ultimately improved the recovery percent of rooted cuttings under water deficit stress. After rehydration, melatonin-treated plants recovered more quickly than untreated plants. In addition, melatonin counteracted the water stress induced accumulation in proline. content. Overall, the results of this study demonstrated that melatonin at 50 μM L-1 (T6) significantly alleviated the adverse effects of water deficit stress on the black pepper plants compared to other stress alleviating chemicals.