短期极端高温对鸡冠花种子活力及早期幼苗生理特性的影响

Effect of Short-term Extreme High Temperature on Seed Vigor of Celosia cristata and Physiological Characteristics of Early Seedlings

摘要:

为明确鸡冠花（Celosia cristata）种子对短期高温的耐受性，种子经短期高温处理30 min，采用纸上发芽法测定种子活力及早期幼苗生理指标。结果表明，60℃下，鸡冠花种子的相对发芽率、发芽势、相对发芽指数分别为101.68%、70%、101.41%，而相对伤害率仅为-1.41%，其早期幼苗根系长度与侧根数、根系活力、叶绿素含量、超氧化物歧化酶（SOD）活性与丙二醛（MDA）含量与对照的差异不显著（P>0.05），而过氧化物酶（POD）与过氧化氢酶（CAT）活性显著高于对照（P<0.05）。温度再升高，种子活力逐渐降低，早期幼苗CAT活性、根系活力与叶绿素含量均迅速降低。这说明鸡冠花种子可耐受的短期极限高温为60℃，且CAT对高温较SOD与POD敏感，可作为评价植物对短期高温反应的一个指标。

关键词:高温胁迫;鸡冠花;种子活力;生理特性

Abstract:

In order to understand the tolerance of cockscomb (Celosia cristata) seeds under short-term extreme high temperature for 30 min, the seed vigor and physiological indexes of early seedlings were studied by germination on paper. The results showed that the relative germination rate, germination energy and relative germination index of cockscomb seeds treated under 60℃ were 101.68%, 70%, 101.41%, respectively, and the relative harm rate was only-1.14%. The root length, lateral root number, root activity, chlorophyll content, SOD activity and MDA content of early seedlings had not significant difference with the control (P>0.05), but POD and CAT activities were significantly higher than the control (P<0.05). The seed vigor, CAT activity, root activity and chlorophyll content decreased with higher temperature. Therefore, the limiting temperature that cockscomb seeds could tolerant was 60℃, the CAT in cockscomb seeds was more sensitive than SOD and POD under high temperature, which could be used as an index to evaluate the reaction of plants to short-term high temperature.

Key words:Heat stress;Cockscomb;Seed vigor;Physiological characteristics