MORPHO-PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES, FODDER YIELD AND QUALITY OF NAPIER GRASS UNDER WATER STRESS

Abstract

Napier grass (Pennisetum purpureum Schumach) is grown in tropical and temperate regions well adopted as a fodder crop because of its high forage productivity and rapid regeneration. It is considered as drought tolerant and shows high water use efficiency. This experiment was done in the shed house of Sher-e-Bangla Agricultural University during the period of April-July, 2021. The study was to investigate the water stressinduced

morphological, physiological and oxidative damages in napier grass and to differentiate between the responses of napier grass to drought and waterlogging conditions. Napier grass was grown for up to 21 days and then exposed to water stress: viz. drought and waterlogging for different durations (7, 14 and 21 days) and also there was maintained control condition. After each stress period, morphological, physiological, and biochemical data were measured following standard procedures. At 50 days after sowing the same parameters were recorded for all treatments and considered as recover data. Plant height, SPAD value, fresh weight, dry weight, relative water content, and fodder yield decreased under both waterlogging and drought stress conditions compared to control. The reduction was higher under drought conditions than in waterlogging. Root length, root shoot ratio, proline, malondialdehyde (MDA) and H 2 O 2 content were higher under stress conditions compared to control. Droughtstressed

plants were more severely affected than waterlogged one. At 50 days after sowing, plant height, shoot fresh weight, shoot dry weight and fodder yield were decreased in plants stressed for longer periods. Root fresh weight, root dry weight, root length and root branch were decreased in plants stressed for 21 days, whereas increased under waterlogging. Proline, MDA and H 2 O 2 content were increased upon exposure to the long duration of stress. Quality parameters such as neutral detergent fibre and acid detergent fibre has been reduced under both stress condition but in case of drought, the reduction was significant. Dry matter, crude fibre, moisture content, hemicellulose and organic matter percentage were reduced under drought and waterlogging stress and whereas crude protein and ash content increased with increase of stress duration. As plants water stressed for 7 days got the highest days for recovery, so it showed better performance and even better than control. Our experiment concludes that napier grass is more sensitive to drought than waterlogging in case of morphology and plants also recovered more efficiently in case of waterlogging than drought. In case of oxidative damage, drought-exposed plants showed more tolerant capacity compared to waterlogged plants.