夏季光温耦合对白及驯化苗生长发育及多糖含量影响

Effects of light-temperature coupling in summer on growth and development and polysaccharide content of domesticated Bletilla striata seedlings

为探究白及驯化苗在光温耦合作用下的生长发育变化,为白及夏季适应性锻炼提供科学依据,以2021年6月移栽大棚的白及组培苗为试验材料,在驯化90 d时,设置不同温度(25、30、35、38℃)和波动光[50μmol/(m^(2)·s),2 min;1 000μmol/(m^(2)·s),2 min]处理模拟夏季白及受到的光温胁迫,测定不同驯化时间白及移栽苗生长状况和生理指标。结果显示:白及移栽苗驯化初期,30与60 d的株高没有差异,但是在茎宽、根数、根长、块茎厚上表现出显著差异(P<0.05),随着驯化时间的延长,在90 d时,株高、叶片长、块茎宽和根长存在显著差异,根冠比在90 d内先升后降,块茎多糖含量90 d较60 d增加了51%。随着温度的升高,白及移栽苗F_(v)/F_(m)、Φ_(PSⅡ)、qP、F’_(v)/F’_(m)和ETR均减少,ΦNPQ和NPQ升高。结果表明,夏季高温和波动光会对白及生长发育产生严重危害,不利于白及的移栽驯化。

In the process of transplanting and acclimating tissue culture seedlings of Bletilla striata in summer,they will face fluctuating light and heat stress at the same time.The tissue culture seedlings of Bletilla striata in June 2021 transplanting greenhouse were used to determine the variation trend of the acclimation time on the growth and physiological indexes of Bletilla striata transplanting seedlings to study the effect of light-temperature coupling in summer on the growth and development changes of acclimated seedlings of Bletilla striata and provide a scientific basis for the adaptive exercise of Bletilla striata in summer.At 90 days of acclimation,the temperature (25℃,30℃,35℃and 38℃)and fluctuating light (50 mmol/(m^(2)·s),2 min;1 000 mmol/(m^(2)·s),2 min) were set to simulate the light and temperature stress of Bletilla striata in summer.The results showed that the root-shoot ratio of Bletilla striata seedlings increased first and then decreased within 90 days.The content of polysaccharide in the tuber increased by 51%in 90 days compared with that in 60 days.Under the combined stress of fluctuating light and high temperature,the amount of carbon assimilated by Bletilla striata was lost 2-3 times.The F_(v)/F_(m),F_(PSⅡ),qP,F’_(v)/F’_(m) and ETR of transplanted Bletilla striata seedlings were reduced,and F_(NPQ) and NPQ were increased with the increase of temperature.It is indicated that the high temperature and fluctuating light in summer cause serious harm to the growth and development of Bletilla striata,which is not conducive to the transplantation and domestication of Bletilla striata.