6-BA预处理对低温弱光胁迫下辣椒幼苗光合特性和内源激素含量的影响

为明确6-BA对辣椒幼苗抗低温弱光性的调控作用,以耐低温弱光性不同的2个品种辣椒幼苗为试验材料,研究了0.08 mmol/L 6-BA预处理对低温(15℃/5℃)弱光(100 μmol/m²·s)下辣椒幼苗叶片气体交换参数、叶绿素含量和内源激素含量的影响。结果表明,低温弱光显著降低了辣椒幼苗叶片的光合速率(Pn)、气孔导度(Gs)、叶绿素a(Chl a)含量、叶绿素b(Chl b)含量、叶绿素T(Chl T)含量和玉米核苷素(ZR)含量,而胞间CO₂浓度(Ci)和脱落酸(ABA)含量显著升高,引起Pn下降的原因主要是非气孔因素;6-BA预处理未改变上述指标随时间的变化趋势,但较之低温弱光处理,6-BA显著降低了Ci和ABA含量,而Pn、Gs、Chl a含量、Chl b含量、Chl T含量以及胁迫前期(6 d)的ZR含量得到显著提高。可见,0.08 mmol/L 6-BA预处理对增强辣椒幼苗抗低温弱光胁迫能力具有显著的效应,且对低温弱光耐性差的品种表现尤其明显。

Effects of 6-BA pretreatment on photosynthesis characteristics and endogenous hormone content in pepper seedlings under low temperature and weak light stress

The aim of the experiment was to explore the regulatory role of 6-benzylaminopurine (6-BA))on resistance ability of low temperature and weak light in pepper seedlings (Capsicum annuum).The effects of 0.08 mmol/L 6-BA pretreatment on gas exchange parameters, chlorophyll content, endogenous hormone content in pepper seedlings leaves under low temperature (15℃/5℃) and weak light (100 μmol/m²·s) stress were investigated. Results showed that the photosynthetic rate (Pn), stomatal conductance (Gs), chlorophyll a (Chl a) content, chlorophyll b (Chl b) content, total chlorophyll (Chl T) content and zeatin riboside(ZR) content of pepper seedling leaves were significantly declined, but intercellular CO₂ concentration (Ci), abscisic acid(ABA) content were significantly increased under low temperature and weak light stress. The reduction in photosynthesis rate caused by low temperature and weak light stress was considered to be a result of non-stomatal restriction mainly. 6-BA had no changed trend of the above index with treatment time prolonged. Under low temperature and weak light stress, treatment with 6-BA significantly declined Ci, ABA content compared with control, but Pn, Gs, Chl a content, Chl b content, Chl T content and ZR content in previous 6 days of strss period were significantly increased.The results suggested that pretreatment with 0.08 mmol/L 6-BA had obviously role on enhanced pepper seedlings tolerance to low temperature and weak light, especially for pepper cultivar were sensitive to low temperature and weak light stress.