低温胁迫对彩椒幼苗生长指标及光合特性的影响

Effects of Low Temperature Stress on Growth Index and Photosynthetic Characteristics of Pepper Seedlings

[目的]探讨低温对彩椒幼苗生长及光合作用的影响,以揭示低温对其伤害机制。[方法]以黄色甜椒花仙子为试材,采用营养钵育苗研究偏低温T1 (19℃/12℃昼/夜)、临界低温T2 (15℃/8℃昼/夜)和对照(CK,25℃/18℃昼/夜)处理对彩椒幼苗生长指标和光合特性的影响。[结果]临界低温T2处理抑制彩椒幼苗生长和光合特性的程度强于偏低温T1;T2与T1处理间彩椒幼苗的叶片数、根长、干重、根冠比、根体积、光合速率、气孔限制值、PSⅡ最大光化学量子产量(Fv/Fm)和光合性能指数(PI)的降低程度达到显著差异(P<0.05);T2处理彩椒幼苗的株高、叶片数、根体积、光合速率、气孔限制值和PI与CK相比依次降低了35.77%、51.32%、93.94%、66.40%、46.91%和57.77%。相关分析表明,低温胁迫下彩椒幼苗光合速率(Pn)与根冠比(R/T)、细胞间隙CO_2浓度(Ci)和PI呈极显著正相关。[结论]T1和T2处理对彩椒幼苗生长指标和光合特性的影响有明显差异,低温时气孔限制是导致彩椒幼苗光合速率降低的主要因素,可根据彩椒幼苗株高和叶片数来判断其受到低温胁迫程度。

[Objective]The purpose of this study was to explore the effect low temperature on the growth and photosynthesis of pepper plants and to reveal the damage mechanism of low temperature on theplants.[Methods]The impact of low temperature on the growth indexes and photosynthetic characteristics of pepper seedlings were studied with sub-optimal low temperature T1(19℃/12℃,day/night),critical low temperature T2(15℃/8℃,day/night),and CK(25℃/18℃,day/night)using yellow pepper variety named“huaxianzi”as the research material.[Results]The growth rate and photosynthetic characteristics of pepper seedlings were strongly inhibited by T2,but not by T1.Significant differences were observed in leaf number,root length,dry weight,root-crown ratio,root volume,photosynthetic rate,stomata limitation,F v/F m and PI of pepper seedlings between T2 and T1.The plant height,leaf number,root volume,photosynthetic rate,stomata limitation,and PI of pepper seedling in T2 were reduced by 35.77%,51.32%,93.94%,66.40%,46.91%,and 57.77%,respectively.Correlation analysis showed that photosynthetic rate of pepper seedlings were significantly and positively correlated with dry weight,root-crown ratio,and Ci and PI under low temperature stress.[Conclusion]There were significant differences in growth index and photosynthetic characteristics of pepper seedlings under sub-optimal and critical low temperature stress.The low temperature stress degree could be adjusted according to the plant height and leaf number of pepper seedling.