烟叶唇柱苣苔的高温半致死温度及其对高温胁迫的生理响应

Semi-lethal high temperature of Chirita heterotricha and its physiological response to high temperature stress

烟叶唇柱苣苔为苦苣苔科唇柱苣苔属多年生草本植物,具有较高的观赏价值和药用价值,但缺少对其人工栽培及其相关生理的研究报道。为给烟叶唇柱苣苔的设施栽培提供生理学依据,以不同温度处理烟叶唇柱苣苔叶圆片,测定电解质渗出率的变化,利用logistic方程拟合并计算其高温半致死温度(LT50),并将植株置于LT50下进行胁迫处理,观测并分析了不同处理时间后叶片中的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性以及丙二醛(MDA)和游离脯氨酸(Pro)含量的变化曲线。结果表明:烟叶唇柱苣苔叶片的电解质渗出率与处理温度的关系,用logistic方程y=100/(1+17.967e-0.068x)拟合良好,得到其高温半致死温度为42.3℃;随着LT50胁迫时间的延长,SOD和POD酶活性先升高后降低,MDA和Pro含量则一直升高,在处理40 h后叶片已经严重失水灼伤,处理48 h后植株萎蔫,已造成了不可逆的伤害。

Chirita heterotricha Merr., a perennial herb of genus Chirita （Gesneriaceae）, has high ornamental and medical values, but researches on its cultivation and related physiology are lack. The leaf discs in C. heterotricha were treated with different temperatures and the electrolyte leakage rates were measured in order to provide a physiological basis. The correlation was fitted with logistic equation to calculate the semi-lethal high temperature （LT50）. After the plants were exposure to the temperature of LT50 for different duration, superoxide dismutase （SOD）, peroxidase （POD） activity malondialdehyde （MDA） content, and free proline （Pro） content were assayed. The results showed that the relation of electrolyte leakage rate to temperature was fitted well with logistic equation y = 100/（1 ＋ 17.967e- 0.068x）, and LT50 was 42.3 ℃ . SOD and POD activities were increased at first, and then decreased as the exposure duration extending at LT_50, however MDA and Pro contents were continuously increased. The leaves lost water severely after 40 h, and the whole plant wilted and could not recover after 48 h.