無患子苗木耐缺水機制之探討

Drought Tolerance Mechanism of ＂Sapindus Mukorossi＂

酈學文(Hsueh-Wen Lih) ； 陳忠義(Chung-I Chen) ； 王亞男(Ya-Nan Wan)

《中華林學季刊》 48卷2期 (2015/06) Pp. 113-126

摘要

本研究以三年生無患子（Sapindus mukorossi）實生苗木為材料，藉不同土壤含水率（RWC, %）模擬充分供水（31.32%）、暫時凋萎點（12.97%）及永久凋萎點（4.96%）三種乾旱缺水程度作一系列生理試驗以探討無患子的缺水時的生存機制。試驗結果顯示：三種處理的苗木生長型態正常，根莖葉生物量分配無顯著變化，僅缺水的苗木氣孔導度下降及生長較差，另表現出羽狀複葉之小葉對天頂夾角顯著增加。由P-VCurve結果得知無患子苗木能有效保留水分並製造壓力差提高水分吸收能力。葉內的變化如滲透調節物質可溶性醣類及脯胺酸的累積。葉片膜脂質中結構性磷脂卵磷脂（PC）及乙醇胺甘油磷脂（PE）含量減少、功能性磷脂醯基甘油磷脂（PG）含量增加，脂肪酸的不飽和度上升等，均顯示無患子苗木有多種應對缺水的防禦機制，屬於耐旱的植物。本研究試驗結果可對造林政策上的生育地條件及樹種選擇上提供參考。

關鍵字

無患子 ； 乾旱逆境 ； 苗木形態 ； 可溶性物質調節 ； 葉片膜脂質 ； 耐旱能力

並列摘要

This study aimed to explore the drought tolerance mechanism of ＂Sapindus mukorossi＂ by phenology and physiology parameters. Three-year-old seedlings with three water treatments based on soil relative water content (RWC) to simulate the degree of drought were used in this study: sufficient water supply (RWC 31.32%), temporary wilting point (RWC 12.97%) and permanent wilting point (RWC 4.96%). The results indicated that ＂S. mukorossi＂ seedlings could survive on each water treatment, no significant difference in the morphological change and biomass allocation, except the increment pinnule angle and stomatal conductance. By P-V curve measure, ＂S. mukorossi＂ seedlings could retain moisture effectively and created water potential gradient to increase water absorbing capacity. The internal phenology changed in osmotic adjustment and leaf membrane lipid changed: decreasing the phosphatidylcholine (PC) and phosphatedylethanolamine (PE), increasing the phosphatidylglycerol (PG), and then increasing the unsaturated ratio of fatty acids. This indicated ＂S. mukorossi＂ seedling was a drought resistance plant which had a variety of mechanisms to defense water deficit.

並列關鍵字

＂Sapindus mukorossi＂ ； Drought stress ； Seedling morphology ； Soluble osmotic adjustment ； Leaf membrane lipid ； Drought tolerance