Abstract: In order to study effects of cross stress induced by salt and drought on seed germination and physiological characteristics of early seedlings of sweet sorghum，Liaotian No.1 sweet sorghum seed was used as the test material. PEG-6000 (0, 50 and 100 g·L^-1) was used  to simulate drought stress, and NaCl (0, 75 and 150 mmol·L^-1) was used  to simulate salt stress. The effects of drought and salt stress on the germination characteristics of sweet sorghum seeds and physiological characteristics of early seedlings were studied.  The results showed that: single or cross stress could inhibit the germination and seedling transformation of sweet sorghum seeds. With the deepening of stress, the antioxidant activity, soluble protein and proline (Pro) content of the seedlings showed an increasing and then decreasing trend, and the malondialdehyde (MDA) and glutathione (GSH) content increased gradually. Compared with single stress, interactive stress under specific conditions could promote the germination of sweet sorghum seeds, enhance the antioxidant activity of seedlings, and increase the content of soluble protein, Pro, MDA and GSH. The results of two-factor variance analysis showed that the effects of single stress on seed germination and seedling physiology of sweet sorghum were more greater than that of drought salt cross stress. According to the comprehensive evaluation of the membership function, sweet sorghum of the stress tested was found  as follows: interaction stress> single PEG stress> single NaCl stress. The  effects of drought salt cross stress on seed germination and physiological characteristics of sweet sorghum seedlings were not simply superimposed by single stress. Compared with single stress, drought salt cross stress could alleviate the effects of salt stress on seed germination and seedling growth physiology of sweet sorghum to a certain extent.

Key words: sweet sorghum, drought salt cross stress, seed germination, physiological characteristics

摘要： 为探讨干旱与盐胁迫及其交互作用对甜高粱种子萌发及早期幼苗生长及生理特性的影响，以辽甜1号甜高粱为试验材料，采用PEG-6000（0、50、100 g·L^-1）和NaCl（0、75、150 mmol·L^-1）模拟不同程度的干旱胁迫和盐胁迫，研究单一胁迫及交互胁迫对甜高粱种子萌发特征和早期幼苗生理特性的影响。结果表明：单一胁迫或交叉胁迫均能抑制甜高粱种子的萌发指标和种苗转化指标，随着胁迫程度加深，早期幼苗的抗氧化物酶活性和可溶性蛋白、脯氨酸（proline，Pro）含量呈先升高后下降趋势，丙二醛（malondialdehyde，MDA）和谷胱甘肽（glutathione，GSH）含量逐渐升高。相比较单一胁迫，特定条件下的交互胁迫可促进甜高粱种苗转化和增强幼苗的抗氧化物酶活性，提高可溶性蛋白、Pro、MDA、GSH含量。双因素方差分析结果验证了单一胁迫对甜高粱种子萌发和幼苗生理的影响比旱盐交叉胁迫影响更大。隶属函数综合评价可知，甜高粱萌发期耐受性强弱为：交叉胁迫>NaCl胁迫> PEG-6000胁迫。旱盐交叉胁迫对甜高粱种子萌发及幼苗生理特性的影响并不是单一胁迫的简单叠加，与单一胁迫相比，旱盐交叉胁迫在一定程度上能够缓解盐胁迫对甜高粱种子萌发及幼苗生长生理的影响。

关键词: 甜高粱, 旱盐交叉胁迫, 种子萌发, 生理特性