自然降温对桂花叶片形态和生理特征的影响  

Effects of naturally decreasing temperature on leaf morphological and physiological traits of Osmanthus fragrans(Thunb.)Lour.

作　　者：郭成圆 孟长军[1] 杜喜春[1] 井富贵 王跃飞 马琳娜 GUO Chengyuan;MENG Changjun;DU Xichun;JING Fugui;WANG Yuefei;MA Linna(School of Biological and Environmental Engineering,Xi’an University,Xi’an 710065,China;Institute of Botany,the Chinese Academy of Sciences,Beijing 100093,China)

机构地区：[1]西安文理学院生物与环境工程学院,西安710065 [2]中国科学院植物研究所,北京100093

出　　处：《生态科学》2021年第4期161-168,共8页Ecological Science

基　　金：西安市科技计划项目(CXY1531WL08);国家博士后基金面上项目(2017M623224)。

摘　　要：叶片是植物对自然降温响应最敏感的器官之一。2017年7月至翌年6月间以西安市园林绿化植物桂花(Osmanthus fragrans(Thunb.)Lour.)为材料,探究自然降温对桂花叶片形态和生理特征的影响,阐明桂花叶片对自然降温过程的适应策略,为北方森林城市建设物种筛选提供理论基础。结果显示:(1)桂花叶面积与月均温度呈显著正相关(r=0.704,P<0.01),叶面积最大值比最小值大了110.71%。桂花比叶重(LMA)在2017年7月为最小值(6.49 mg·cm^(-2)),翌年1月升至最大(14.78 mg·cm^(-2)),LMA与叶片相对含水量(RWC)呈显著负相关关系(r=-0.563,P<0.01)。月均温度从30.5℃下降到-0.9℃,桂花叶片干物质含量(LDMC)呈现缓慢增加的趋势。(2)桂花叶片气孔以密而小的方式应对自然降温,密度与长度显著负相关(r=-0.446,P<0.01),气孔密度和长度分别与月均温度呈负和正相关(r=-0.509,P<0.01;r=0.541,P<0.01);(3)桂花叶片叶绿素a含量在7月到10月维持在较高值(18.66 mg·g^(-1)),12月较此值下降了44.3%。叶绿素b含量在12月达到最大值7.56 mg·g^(-1),存在显著的月份差异(P<0.01),类胡萝卜素含量在自然降温过程中呈现缓慢下降的趋势,最大值比最小值高出36.5%。桂花RWC与月均温度呈正相关(r=0.548,P<0.01),月均温度30.5℃时为最高值80.3%,翌年3月降至最低,下降幅度50.9%(P<0.01)。研究表明,桂花为应对北方秋冬季大幅度的自然降温将通过增加叶片干物质的投入和储备,调整气孔形态为密而小,降低叶片相对水分含量,控制体内温度与水分的平衡,来达到叶片生理与形态之间的有效整合。Leaves are one of the most naturally decreasing temperature-sensitive parts of a plant.In this study,Osmanthus fragrans(Thunb.)Lour.,a landscape plant in Xi'an city,was used as material and its leaves were collected monthly from July 2017 to June 2018.The aims were to explore the effects of naturally decreasing temperature on the morphological and physiological traits of Osmanthus fragrans leaves and to clarify the adaptive mechanism of Osmanthus fragrans leaves to natural cooling process.It provides a theoretical basis for species selection of Xi'an to be a forest city.The results showed that:(1)leaf area of Osmanthus fragrans was positively correlated with the monthly mean temperature(MMT)(r=0.704,P<0.01).The maximum leaf area was 110.71%larger than the minimum.Leaf mass per unit area(LMA)of Osmanthus fragrans was the minimum(6.49 mg·cm^(-2))in July 2017.Then the LMA reached to the maximum(14.78 mg·cm^(-2))in January next year.LMA was negatively correlated with relative water content(RWC)of leaves(r=-0.563,P<0.01).Leaf dry matter content(LDMC)of Osmanthus fragrans increased slowly during natural cooling,from 30.5℃ to-0.9℃;(2)Osmanthus fragrans responded to natural cooling with smaller and more dense stomata.The stomatal density was negatively correlated with the stomatal length(r=-0.446,P<0.01).The stomatal density and length of Osmanthus fragrans leaves were negatively and positively correlated with the MMT,respectively(r=-0.509,P<0.01;r=0.541,P<0.01);(3)the content chlorophyll a in Osmanthus fragrans leaves was 18.66 mg·g^(-1) in July to October 2017,and 44.3%decreased compare to this in December.The content chlorophyll b in Osmanthus fragrans leaves was significantly different among months(P<0.01)and reached peak(7.56 mg·g^(-1))in December.The carotenoids content decreased slowly during naturally decreasing temperature.The maximum value of carotenoids content was 36.5%higher than the minimum value.The leaf relative water content(RWC)of Osmanthus fragrans was positively correlated with the MMT(r=0.548

关 键 词：叶面积 气孔密度 比叶重 适应策略 功能性状 

分 类 号：Q14[生物学—生态学]