壳聚糖对盐胁迫下小麦种子萌发及幼苗生理特性的影响

Effect of chitosan on seed germination and seedling physiological characters of wheat under salt stress

以小麦品种偃展08231和小偃986为材料,在150 mmol·L^(-1)Na Cl胁迫处理下,研究了不同浓度的外源壳聚糖(CTS)对小麦种子萌发及幼苗生理特性的影响。结果表明:盐胁迫下,0.1%~0.5%CTS浸种预处理的小麦种子具有较高的发芽势、发芽率、发芽指数、活力指数和ɑ-淀粉酶活性,两个品种均以0.3%的CTS处理效果最佳,与对照相比偃展08231和小偃986的发芽势、发芽率、发芽指数和活力指数分别提高27.84%和25.33%、9.94%和19.95%、38.49%和32.30%,72.72%和82.83%;0.1%~0.5%CTS处理小麦幼苗具有较高的株高、鲜重和干重,其超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性和脯氨酸含量以及根系活力均较高,而丙二醛(MDA)含量较低,其中以0.3%CTS处理效果最好,与对照相比偃展08231和小偃986的株高、鲜重和干重分别提高32.60%和36.74%、26.08%和38.77%、24.05%和35.87%。CTS对小偃986盐胁迫的缓解作用强于对偃展08231的作用。说明一定浓度的外源CTS浸种可促进盐胁迫下小麦种子萌发和幼苗生长,减缓盐胁迫伤害。

Two different wheat varieties Yanzhan 08231 and Xiaoyan 986 were used as materials to examine the effect of exogenous chitosan （CTS） on seed germination and seedlings physiological characteristic under the treatment of 150 mmol· L^-1 NaCl. The result showed that the germination energy, germination percentage, germination index, vigor index and relative a - amylase activity of the seed were increased after being presoaked with exogenous 0.1% - 0.5 % CTS. 0.3% CTS had the best effect, showing 27.84% and 25.33%, 9.94% and 19.95%, 38.49% and 32.30%, and 72.72% and 82.83% increases from the control in germination energy, germination percentage, germination index, vigor index of Yanzhan 08231 and Xiaoyan 986 seeds, respectively. With the treatment of 0.1% - 0.5 % CTS, the wheat seedling had higher plant height, fresh weight, dry weight, activities of superoxide dismutase （SOD） and peroxidase （POD）, proline content and root activities, but lower content of malondialdehyde （MDA） than the control, and 0.3 % CTS treatment also gave the best result. Compared with the control, the plant height, fresh weight, dry weight of Yanzhan 08231 and Xiaoyan 986 seedlings were increased by 32.60% and 36.74%, 26.08% and 38.77%, 24.05% and 35.87%, respectively. Xiaoyan 986 was more salt tolerant than Yanzhan 08231, and mitigation effect of CTS on salt stress was also more obvious on Xiaoyan 986 than Yanzhan 08231. These results indicated that the exogenous CTS （chitosan） could effectively mitigate the injuries of salt stress and increase salt tolerance of wheat seeds and seedlings. The best treatment concentration of chitosan was O. 3 %. When the concentration of chitosan was higher than 0. 5 %, no mitigation effect was observed under the salt stress.