摘要
【目的】探索棕榈幼苗的水分生理、光合作用及叶绿素荧光在不同干旱胁迫及复水条件下的响应和适应能力,进一步揭示棕榈的抗旱机制,为我国干旱、半干旱地区良种选择提供理论依据。【方法】以2年生棕榈实生苗为试验材料,运用盆栽渐进式干旱胁迫的方法,在棕榈幼苗的致死临界值时进行复水试验,测定并分析不同水分处理条件下棕榈幼苗叶片的含水量、光合色素含量、光合作用及叶绿素荧光参数等指标。【结果】随着土壤水分的缺失,棕榈幼苗可获得水分减少,棕榈幼苗叶片的组织含水量、相对含水量、叶绿素a质量分数、叶绿素b质量分数、类胡罗卜素质量分数、总叶绿素质量分数、净光合速率、气孔导度、蒸腾速率、最大荧光、PSⅡ最大光化学效率、PSⅡ实际光化学量子效率、相对电子传递速率以及光化学淬灭系数逐渐降低,而自然饱和亏、胞间CO_(2)浓度、最小荧光、非光化学淬灭系数逐渐升高,水分利用率则先升高后降低。干旱胁迫7 d棕榈幼苗遭受轻度的干旱胁迫,其叶绿素荧光参数差异不显著。干旱胁迫前16 d棕榈幼苗的净光合速率下降是由于“非气孔限制”,干旱胁迫16 d及之后,棕榈幼苗的净光合速率下降是由于“气孔限制”。干旱胁迫20 d棕榈幼苗遭受重度干旱胁迫,其体内的水分亏缺严重,光合色素遭到了严重的损伤,已达到棕榈幼苗耐旱性的阈值。自然干旱胁迫下,当土壤含水量为21.12%时棕榈幼苗的致死率大于50%,此时为棕榈幼苗的致死临界值。对临界死亡的棕榈幼苗复水后,各指标均有一定程度的恢复,其中只有水分利用率、最大荧光、PSⅡ最大光化学效率、光化学淬灭系数恢复至干旱胁迫前水平。【结论】棕榈幼苗通过关闭气孔,降低蒸腾速率、净光合速率、光化学利用效率,提高水分利用率、热能消耗等来抵御不良的干旱环境,�
【Objective】To explore the responses and adaptability of water physiology,photosynthesis and chlorophyll fluorescence of Trachycarpus fortunei seedlings under different drought stress and rewatering conditions,and reveal the drought resistance mechanism of Trachycarpus fortunei.It provides theoretical and practical basis for selection of superior varieties in arid and semi-arid areas of China.【Method】Two-year-old seedlings of Trachycarpus fortunei were used as experimental materials in this study,the rewatering test was carried out at the lethal critical value of Trachycarpus fortunei seedlings by the method of progressive drought stress in pot culture.The leaf water content,photosynthetic pigment content,photosynthesis and chlorophyll fluorescence parameters and so on of Trachycarpus fortunei seedlings were measured and analyzed under different water treatments.【Result】With the loss of soil moisture,Trachycarpus fortunei seedlings could available moisture decreases,Trachycarpus fortunei leaf water content,leaf relative water content,chlorophyll a and chlorophyll b,carotene,total chlorophyll,photosynthetic rate,stomatal conductance,transpiration rate,maximum fluorescent,maximum photochemical efficiency,photochemical quantum efficiency,electron transport rate,photochemical quenching coefficient gradually reduced,while the other,natural water-saturated deficit,intercellular CO_(2) concentration,initial fluorescence,non-photochemical quenching coefficient gradually rise,water use efficiency is increased before they are reduced.After 7-day mild drought stress,the chlorophyll fluorescence parameters of Trachycarpus fortunei seedlings had no significant difference.Under 16-day drought stress ago,photosynthetic rate decreased due to“non-stomatal restriction”,while under 16-day drought stress later,photosynthetic rate decreased due to“stomatal restriction”.Under 20-day drought stress,the Trachycarpus fortunei seedlings suffered severe drought stress,the water deficit in their bodies was serious,and the
作者
孙娅楠
赵杨
赵渊祥
曹海
龙建磊
SUN Yanan;ZHAO Yang;ZHAO Yuanxiang;CAO Hai;LONG Jianlei(College of Forestry,Guizhou University,Guiyang 550025,Guizhou,China;Institute for Forest Resources&Environment of Guizhou,Guizhou University,Guiyang 550025,Guizhou,China)
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2021年第9期45-52,共8页
Journal of Central South University of Forestry & Technology
基金
贵州省重大科技专项(黔科合重大专项(2014)6024-1)。
关键词
棕榈
光合作用
叶绿素荧光
干旱胁迫
复水
Trachycarpus fortunei
photosynthesis
chlorophyll fluorescence
drought stress
rewatering
