6个彩叶桂品种对低温胁迫的生理响应及抗寒性评价

Physiological responses and evalution of cold resistance of six Osmanthus fragrans cultivars under low temperature stress

【目的】研究6个彩叶桂Osmanthus fragrans品种对低温胁迫的生理响应,并进行抗寒性评价,以利于彩叶桂的推广和应用。【方法】以6个彩叶桂品种离体叶片为材料,进行人工低温胁迫,共设0、-4、-8、-12、-16、-20、-24、-28℃共8个温度梯度,测定其相对电导率、丙二醛质量摩尔浓度、可溶性糖质量分数、可溶性蛋白质质量分数、超氧化物歧化酶活性、过氧化物酶活性等6项生理指标,结合隶属函数法,探讨几种彩叶桂对低温胁迫的响应,进行抗寒性评价。【结果】不同低温胁迫下6个彩叶桂品种的相对电导率的变化均为"S"型曲线,Logisitic回归分析可知:‘傲霜’‘Aoshuang’、‘冬荣’‘Dongrong’半致死温度较低,分别为-12.95、-11.80℃;‘银碧双辉’‘Yinbi Shuanghui’最高,为-8.15℃。低温胁迫下,彩叶桂叶片丙二醛质量摩尔浓度随温度降低,总体上呈先增加后减少再增加的变化规律,并且各品种的变化幅度有所不同。随温度的降低,各品种可溶性糖、可溶性蛋白质质量分数总体上均为先升后降,但增加幅度和拐点温度并不相同。‘罗彩1号’‘Luocai No.1’、‘傲霜’超氧化物歧化酶活性表现出"上升—下降—再上升—再下降"的趋势,其余品种超氧化物歧酶活性变化均呈先升后降的趋势。不同品种过氧化物酶活性的变化趋势不尽相同,‘永福幻彩’‘Yongfu Huancai’、‘银碧双辉’大致呈现先上升后下降的趋势,‘罗彩1号’、‘罗彩2号’‘Luocai No.2’、‘傲霜’、‘冬荣’过氧化物酶活性呈"下降—上升—下降"的趋势。抗寒性评价可知:6个品种抗寒能力从强到弱依次为‘傲霜’、‘冬荣’、‘罗彩2号’、‘罗彩1号’、‘永福幻彩’、‘银碧双辉’。【结论】低温胁迫条件下,6个彩叶桂品种叶片生理生化指标均发生了明显的变化,综合来看,‘傲霜’‘冬荣’‘罗彩2号’这3个品种较能适应北方气候。图6表2参35。

[Objective]The objective of this study is to investigate the physiological response of six cultivars of Osmanthus fragrans to low temperature stress and evaluate their cold resistance,so as to facilitate their popularization and application.[Method]The detached leaves of six cultivars of O.fragrans were used as experimental materials under artificial low temperature stress,with a total of 8 temperature gradients of 0,-4,-8,-12,-16,-20,-24,-28℃.Their physiological indexes such as relative conductivity(REC),malondialdehyde(MDA),soluble sugar(SS),soluble protein(SP),superoxide dismutase(SOD)and peroxisome(POD)were measured.The response of several cultivars of O.fragrans to low temperature stress was studied by the membership function method,and the cold resistance evaluation was completed.[Result]The changes of REC of six cultivars under different low temperature stress were S-shaped curve.Combined with logistic regression analysis,the semi-lethal temperature of each cultivar was calculated.’Aoshuang’and’Dongrong’had lower values,which were-12.95 and-11.80℃respectively,and’Yinbi Shuanghui’had the highest value of-8.15℃.Under low temperature stress,the MDA content in leaves of six cultivars of O.fragrans increased first,then decreased and then increased with the decrease of temperature,and the rangeability of each cultivar was different.With the decrease of temperature,the content of SS and SP of all cultivars increased first and then decreased,but the increasing range and inflection point temperature were not the same.The SOD activity of’Luocai No.1’and’Aoshuang’showed a trend of"up–down–up–down",while the SOD activity of other cultivars showed a trend of first up and then down.The change trend of POD activity in different cultivars was different.The POD activity of’Yongfu Huancai’and’Yinbi Shuanghui’generally showed an upward trend at first and then a downward trend,and the POD activity of’Luocai No.1’,’Luocai No.2’,’Aoshuang’and’Dongrong’showed a trend of"down–up–down".The cold resistance of six cultivars was evaluated by the membership function method,and the order of cold resistance from strong to weak was’Aoshuang’,’Dongrong’,’Luocai No.2’,’Luocai No.1’,’Yongfu Huancai’,and’Yinbi Shuanghui’.[Conclusion]Under low temperature stress,the physiological and biochemical indexes of leaves of six cultivars of O.fragrans change significantly.According to the membership function method,the three cultivars’Aoshuang’,’Dongrong’,and’Luocai No.2’can better adapt to the temperature in northern China.[Ch,6 fig.2 tab.35 ref.].