Effects Of Low Temperature And Weak Light And Exogenous Calcium On Growth And Physiological Metabolism Of Luffa

Temperature and light are important environmental factors affecting plant growth and development.Luffa is a kind of thermophilic plant,and it is one of the major fruit vegetables cultivated in the south in early spring and summer.But overwintering luffa seedlings in the southern are often affected by the low temperature and the weak light,and then cause the loss of production.In this experiment,luffa as material was tested to study the influence of the low temperature and the weak light on the growth and physiological indices of seedlings,the effects of exogenous calcium on cold-resistant capacity of luffa and the effects of different light quality of light on the ability of seedling growth of luffa.The main findings are as follows:1?Under low temperature treatment,the growth of luffa seedlings were greatly affected.Seedling cotyledons of luffa began wilting,and plants stop growing at 5??2? and 8??5? condition after 6 days;the content of chlorophyll a,b,and carotenoid were significantly reduced under low temperature stress.Meanwhile,the low temperature lead to the reduction of photosynthetic rate and water use efficiency of luffa seedlings,and increased water evaporation.Low temperature raised the content of soluble sugar,proline,soluble protein and MDA,and the membrane permeability of luffa.With the extension of treatment time,SOD activity was increased first and then decreased,while POD was rising,CAT declined.2?After using different concentrations of calcium chloride treated luffa seedlings,we determined soluble sugar,soluble protein,relative conductivity,proline content,MDA content and antioxidant enzyme activities.The results showed that different concentrations of calcium chloride treatment could increase luffa seedlings resistance,which 12mmol·L-1 Ca2+had best effect.3?The growth of luffa seedlings were effected by varying degrees of weak light treatment.At 50%and 70%of the low light conditions,luffa growth was inhibited,chlorophyll and carotenoid were reduced in different degrees.With the weaking of light intensity,the soluble protein content,proline content,membrane permeability,SOD and POD activity increased gradually,while the soluble sugar content and CAT activity decreased.4?Luffa growth was affected after weak light stress.And the calcium chloride treatment to some extent alleviated the adversity stress of luffa.But there was a certain concentration effect,in which 16mmol·L-1 Ca2+ treatment had the best effect.Sodium chloride had no obvious relieve effect,on the contrary,with the concentration increased,the damage was heavier caused by weak light.5?After supplement of different light qualities of light,red light was conducive to increasing the content of chlorophyll a and chlorophyll b;yellow light could increase the content of carotenoids(Car),and blue light could increase the content of soluble sugar and the content of protein.SOD,POD and CAT activity in the luffa leaves firstly increased and then decreased and the enzyme activities were at the highest level after 30days of treatment with different light qualities.The MDA content in leaves of luffa in red,blue and white light was significantly lower than the control,and the effect of blue light was the most obvious.