In order to study the effects of exogenous growth regulators on morphological and physiological indexes of seedlings under low-temperature and low-light stress,seven exogenous growth regulators were used to treat chilli seedlings with'Xingshu 301',including 0.1 μmol·L-1 oleandrin lactones(BRs),100 μmol·L-1 melatonin(MT),500 μmol·L-1 salicylic acid(SA),100 μmol·L-1 abscisic acid(ABA),300 mg·L-1 6-benzyl adenine(6-BA),100 μmol·L-1 methyl jasmonate(MeJA),and 20 μmol·L-1 monocrotaline(GR24).The results showed that,compared with the ambient control,the stoutness index of chilli seedlings under low-temperature low-light stress was significantly reduced,and the contents of soluble sugars,proline and malondialdehyde in the leaves were significantly increased;the chlorophyll content and catalase activity were significantly decreased.Compared with the low-temperature and low-light control,the seedling index and leaf soluble sugars,proline,chlorophyll content and catalase activity were significantly increased,malondialdehyde content was decreased,chlorophyll fluorescence parameter Fv/Fm and photochemical burst coefficient(qP)were increased,and non-photochemical burst coefficient(NPQ)was decreased by the treatments of the exogenous growth regulators.However,the effects of different exogenous growth regulators to alleviate low-temperature and low-light stress varied,and ABA,MT,and GR24 were more effective.The effect of exogenous growth regulators was obvious in the early stage of low-temperature and low-light stress(5 days),and the difference was not significant after 5 days of growth resumption.It has shown that low temperature and low light stress would affect the growth of chilli seedlings,and exogenous growth regulator treatments were effective in alleviating the damage of adversity stress on chilli seedlings in the early stage;there were differences in the effects of different exogenous growth regulator treatments,and ABA,MT,and GR24 significantly enhanced the ability of chilli seedlings to tolerate low temperature and low light,of which 100 μmol·L-1 ABA had the best effect.
Capsicum annuum L.growth regulating substanceslow temperature and low light stressgrowth physiology