甜菜碱对盐碱胁迫下海岛棉幼苗光合作用及生物量积累的影响

研究盐碱胁迫下甜菜碱对海岛棉幼苗光合作用和生物量积累的影响,及在生长发育中的作用,为其在海岛棉抗盐碱栽培生产中的应用提供参考。本研究采用三因素随机区组试验设计,以新海35号和新海48号为试材,盐碱浓度为0、120、180、240 mmol L-1,甜菜碱浓度为0、30、60 mmol L-1。随着盐碱浓度升高, 2种海岛棉幼苗株高、叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)、植株鲜重及干重积累均呈显著下降趋势,喷施甜菜碱后海岛棉幼苗生长发育、光合特性及生物量积累均有不同程度的提高;同一盐碱浓度下,随着甜菜碱浓度升高,海岛棉幼苗各项指标均先升高后降低,且30 mmol L-1>60 mmol L-1>0 mmol L-1, 30 mmol L-1与60 mmol L-1甜菜碱浓度之间无显著差异;同一甜菜碱浓度下,随着盐碱浓度的升高,对海岛棉幼苗各项指标的促进作用均表现为持续下降趋势,在盐碱浓度120 mmol L-1下,喷施30 mmol L-1甜菜碱对提高海岛棉光合气体参数具有显著效果,进而提高了海岛棉幼苗株高及增加了生物量积累;新海35号较新海48号的促进作用更为明显。因此,在盐碱地(0~120 mmol L-1)栽培中,叶面喷施甜菜碱(30 mmol L-1)对海岛棉生长发育及光合作用具有显著改善作用。

Effects of glycinebetain on photosynthesis and biomass accumulation of island cotton seedlings under saline alkali stress

Xinhai 35 and Xinhai 48 varieties were used to study the effects of glycinebetain on photosynthesis, biomass accumulation and the role in the growth and development of sea island cotton seedlings under salt alkali stress, which will provide a reference for the application of glycinebetain in the salt alkali cultivation of island cotton. The concentration of saline alkali was 0, 120, 180, 240 mmol L ^-1, and the concentration of glycinebetain was 0, 30, 60 mmol L ^-1. With the increase of saline alkali concentration, island cotton seedling plant height, net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), plant fresh and dry weight accumulation showed a significant downward trend, but after glycinebetain spraying, the growth, photosynthesis and biomass accumulation of sea island cotton seedlings were improved in different degrees. Under the same saline alkali concentration, the above indices of island cotton seedlings increased first and then decreased with the increase of glycinebetain concentration. Under the same glycinebetain concentration, the promotion degree of each index of island cotton seedlings showed a continuous downward trend with the increase of salinity and alkali concentration. Under 120 mmol L ^-1 saline-alkali concentration, spraying 30 mmol L ^-1 glycinebetain had a significant effect on improving the photosynthetic performance, thereby increasing the plant height and biomass accumulation of island cotton seedlings, which was more effective in Xinhai 35 than in Xinhai 48. Therefore, in the cultivation of saline alkali soil (0-120 mmol L ^-1), foliar application of glycinebetain (30 mmol L ^-1) can significantly improve the growth and photosynthesis of island cotton.