耐性不同辣椒幼苗光合和PSII光化学效率对低温弱光的响应

Responses of Photosynthesis and PSII Photochemistry Activities to Chilling Treatment under Low Irradiance in Two Cultivars of Pepper

模拟节能日光温室低温弱光逆境,研究了耐性不同辣椒幼苗光合作用和光化学效率对低温弱光的响应。结果表明,在15℃/5℃(昼/夜)、100μmol/(m2·s)PFD条件下处理1～7天后,耐低温弱光的佳木斯辣椒叶片的羧化效率(CE)、气孔导度(Gs)、光合能力及RuBP再生速率的降低幅度均显著地低于冷敏感的陇椒6号。处理1～7天后,佳木斯叶片的PSII最大光化学效率Fv/Fm、实际光化学效率ΦPSⅡ和光化学猝灭系数qP均无显著变化,处理3天后,陇椒6号叶片的Fv/Fm、ΦPSⅡ和qP降低,且随处理时间延长,降低幅度加大。陇椒6号的气孔对低温弱光非常敏感,胁迫1天后,最大气孔导度即降低了66.41%,净光合即检测不出,而佳木斯的只降低了15.02%,处理的前5天能检测到净光合速率。低温弱光处理后,两品种辣椒幼苗叶片的光合色素含量均降低,佳木斯叶片的Chla/Chlb不变,Car/ChlT下降;陇椒6号的Chla/Chlb和Car/ChlT增大。在低温弱光胁迫下,佳木斯叶片的超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性显著高于陇椒6号。处理前期,佳木斯的SOD、APX、GR活性同步提高,陇椒6号的GR活性不能与SOD、APX同步升高。

Responses of photosynthesis and PSII photochemistry activities to chilling treatment under low irradiance, a simulated unfavorable condition of sunshine greenhouse in deep winter, were investigated in two cultivars of pepper with different chilling sensitivity. Chilling treatment （15 ℃/5 ℃, day/night） under low irradiance （100 μmol/（m^2· s）, 12h photoperiod） for 1-7 days resulted in less decreases in carboxylation efficiency （CE）, stomatal conductance （Gs）, photosynthesis capacity and maximum regeneration of RuBP in chilling-tolerant pepper ＂Jiamusi＂ than in chilling-sensitive pepper ＂Longjiao No. 6＂. Chilling treatment under low irradiance for 1-7 days had little effects on Fv/Fm, φPSⅡ and qP in Jiamusi. But such treatment caused decreases in Fv/Fm, φPS Ⅱ and qP in longjiao No. 6 after 3 days. The Gs of Longjiao No. 6 was highly sensitive to chilling treatment under low irradiance, and the maximum Gs decreased by 66.41% in Longjiao No. 6, but only by 15.20% in Jiamusi when treated 1 day. In Longjiao No. 6, Pn could not be detected when treated 1 day, but in Jiamusi it could be until treated 5 days. Chloroplast pigments contents decreased in leaves of both two cuhivars of pepper during chilling treatment under low irradiance. Chla / Chlb ratios changed little, and Car/ChlT ratios reduced in leaves of Jiamusi, but Chla/Chlb ratios and Chla/Chlb ratios increased in leaves of Longjiao No. 6 under low temperature and low irradiance. During the treatment, activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX） and glutathione reductase （GR） were higher in Jiamusi than in Longjiao No. 6. Chilling treatment under low irradiance for 1-3 days enhanced the activities of SOD, APX and GR simultaneously in Jiamusi. But GR activity was not enhanced as the activities of SOD and APX in Longjiao No. 6 during the treatment.