华南地区5种苗木叶水势与土壤含水量的关系

摘要

Five species in South China area ,two fast-growing species ( Eucalyptus urophylla ×Eucalyptus grandis and bamboo-wil-low) and three Karst area species ( Rhaphiolepis indica,Evodia glabrifolia,and Zenia insignis) were tested by pot experiment to study the relationships of soil water content and leaf water potential under drought stress , and to estimate water holding capacity and drought resistance of five kinds of seedings from the perspective of water potential changes .The results showed that:①soil water con-tent and leaf water potential were used to fit curve ,exponentiation was best for Rhaphiolepis indica ( R2 =0.98 ,P<0.01 ) ,logarith-mic was best for Eucalyptus urophylla × Eucalyptus grandis,bamboo-willow,Evodia glabrifolia,and Zenia insignis( R2 >0.92,P<0.01 ).②Rhaphiolepis indica and bamboo willow maintained a high leaf water potential ,indicating a strong ability to maintain mois-ture and to delay dehydration;leaf water of Eucalyptus urophylla ×Eucalyptus grandis,Evodia glabrifolia and Zenia insignis Sharply declined in moderate and sever drought ,its ability to maintain moisture was weak.③Three species in Karst area ( Rhaphiolepis indi-ca,Evodia glabrifolia,and Zenia insignis),leaf water potential of Rhaphiolepis indica decreased rapidly,in same soil water content, leaf water of Rhaphiolepis indica was significant higher than Zenia insignis and Evodia glabrifolia,drought resistance of Rhaphiolepis indica was higher than Zenia insignis and Evodia glabrifolia,for fast-growing species ( Eucalyptus urophylla ×Eucalyptus grandis and bamboo-willow),leaf water potential of bamboo-willow decreased rapidly than Eucalyptus urophylla ×Eucalyptus grandis,and indica-ting higher drought resistance.%利用盆栽模拟干旱胁迫条件，研究华南地区速生树种尾巨桉、竹柳以及石灰岩地区常见造林树种石斑木、楝叶吴茱萸、任豆苗木土壤含水量与叶水势关系，并从叶水势变化角度对5种苗木的保水能力和抗旱能力进行评价。试验结果表明：①通过拟合土壤含水量与叶水势关系得出：石斑木以乘幂方程拟合最好，R2＝0.98（ P＜0.01）；尾巨桉、任豆、竹柳和楝叶吴茱萸以对数方程拟合最好，R2＞0.92（ P＜0.01）。②石斑木和竹柳在整个干旱过程中能保持较高的叶水势，说明其保持水分的能力较强，具有较高的延迟脱水的能力；尾巨桉、楝叶吴茱萸、任豆在受到中度和重度干旱胁迫时叶水势急剧下降，保持水分的能力较弱。③在干旱胁迫条件下，3个石灰岩树种中石斑木叶水势降低较快，且在土壤含水量相同时石斑木叶水势显著高于任豆和楝叶吴茱萸，说明石斑木抗旱性强于楝叶吴茱萸和任豆；而2个速生树种以竹柳的水势降低较快，表现出较强的抗旱性能。