油菜素内酯对裸燕麦常温和高温胁迫下生长形态及生理特性的影响

目的]探讨油菜素内酯对裸燕麦生长发育和抗氧化代谢的调节机理,为提高裸燕麦耐热性和生产力提供参考依据.方法]以喷蒸馏水为对照(CK),对长势一致的裸燕麦喷施浓度为0.01、0.10和1.00 mg/L的油菜素内酯,进行常温(白天20℃/晚上15℃)和高温(白天38℃/晚上25℃)环境培养,处理7 d后进行形态和生理生化指标测定.结果]在常温下,喷施油菜素内酯可增加裸燕麦的叶绿素含量,增强光合作用,促进有机物质的积累,进而提高其生物量,其中株高、鲜重和干重以1.00 mg/L处理最高,分别高于常温CK 23%、26%和123%;叶绿素a、叶绿素b和叶绿素总含量均以0.10 mg/L处理最高,分别高于常温CK 81%、98%和86%.高温胁迫下喷施油菜素内酯可明显提高裸燕麦的耐热性,提高其根系活力及抗氧化酶活性,降低膜脂过氧化产物丙二醛(MDA)含量,其中以0.10 mg/L处理根系活力最高(154.16μg/g·h),MDA含量最低(17.54 nmol/g),可溶性蛋白、可溶性糖含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性均达最大值,分别为28.75 mg/g、26.75 mg/g、842.71 U/gFW和199.43 U/g·min.结论]常温环境下,喷施0.10和1.00 mg/L的油菜素内酯对裸燕麦生长发育的促进作用最显著;高温胁迫下,喷施0.10 mg/L的油菜素内酯对提高裸燕麦耐热性的效果最佳.

Effects of brassinolide on growth morphology and physiological characters of Avena nuda under room and high temperature stresses

Objective]The regulation mechanism of brassinolide on growth and antioxidant metabolism of Avena nuda was explored,so as to provide some references for improving productivity and heat resistance of A. nuda. Method]The ex-periment set up the treatment of spraying distilled water as control(CK). Brassinolide of different concentrations(0.01,0.10 and 1.00 mg/L) were sprayed on leaves of A. nuda under room temperature(day 20 ℃/night 15 ℃) and high temperature (day 38 ℃/night 25 ℃) stresses to explore the effects of brassinolide on morphological indexes and physiological and bio-chemical indexes after 7 d. Result]Under room temperature, spraying brassinolide increased chlorophyll content in A. nuda, strengthened photosynthesis and increased biomass accumulation. Plant height,fresh and dry weight of A. nuda were the highest in 1.00 mg/L brassinolide and were 23%, 26% and 123% higher than those of CK. Chlorophyll a,chlorophyll b and total chlorophyll contents of A. nuda treated by 0.10 mg/L were the highest and 81%, 98% and 86% higher than those of CK. Brassinolide significantly improved heat resistance under high temperature by increasing the activity of root system and antioxidant enzyme activity, reducing malondialdehyde (MDA ) content. In 0.10 mg/L brassinolide treatment group , root activity was the highest (154.16 μg/g·h)and MDA content was the lowest(17.54 nmol/g). Soluble protein content (28.75 mg/g),soluble sugar content (26.75 mg/g),superoxide dismutase (SOD) activity (842.71 U/gFW) and cata-lase (CAT) activity (199.43 U/g·min) reached the maximum. Conclusion]Under room temperature, spraying 0.10 and 1.00 mg/L brassinolide has the optimal improving effects on growth of A. nuda. Under high temperature stress, spray-ing 0.10 mg/L brassinolide has the best effects on improving heat resistance of A. nuda.