单 位：
华南农业大学林学院;中国林业科学研究院林业研究所
摘 要：
植物节水性是抗旱性比较的重要指标之一,为造林选种提供重要参考依据。为挑选适合西北地区大面积造林的楸树无性系,在楸树生长旺盛期对3个无性系(7080、004-1及015-1)进行为期18天的盆栽自然干旱胁迫研究,比较分析3个无性系干旱期内耗水量、蒸腾量以及水分利用能力的变化。研究结果显示:3个无性系的土壤含水量随着干旱胁迫加剧而显著下降,无性系7080土壤含水量干旱胁迫前中期(第0天至第10天)显著高于其余两个无性系,正常水分条件下达到45.92±1.35%,但10天后三者无显著差异;3个无性系叶水势也随干旱胁迫而下降,但无显著差异,末期时叶水势平均在-3.0770±0.1457 MPa,变化区间为-0.658±0.057~-3.178±0.064 MPa;3个无性系干旱期间耗水量显著下降,在耗水速率日变化的比较中发现,无性系7080正常水分条件耗水速率显著低于其他两个无性系,干旱后差异不显著,但其耗水速率下降至几乎为0 g·h-1是在第10天,而其余两个无性系在第6天后即达到0 g·h-1水平;在蒸腾速率的变化中3个无性系表现一致,均随着干旱加剧而显著下降;而正常水分条件下蒸腾速率日变化比较后发现:无性系7080和004-1均出现12:00最低点,14:00达到第二个峰值("双峰")现象,而015-1在14:00时出现最低点1.548±0.104μmol·m-2s-1后不再上升。研究结果表明:楸树正常水分条件下10:00时蒸腾速率(Tr)与日间耗水总量呈良好线性关系,拟合公式为y=18.798x-81.7(R2=0.9815,p=0.0372),可利用该指标对于不同无性系耗水总量进行比较;干旱胁迫下土壤含水量变化值(y)与耗水总量变化(x)呈良好拟合关系,公式为y=1.9422x2+9.4586x+69.799(R2=0.9815,p=0.0372)。利用土壤含水量/耗水总量分析3个无性系水分利用能力后发现015-1水分利用能力较004-1及7080弱;楸树日间最大耗水速率/平均耗水速率在正常状态与重度干旱时期均稳定在1.38,在干旱过程中出现波动,其中015-1与004-1波动较大(即耗水速率起伏较大),而7080则稳定在一定范围内,体现较好水分利用能力。
译 名：
Compara tion of water consumption and transpiration of 3 Catalpa bungei clones under drought
作 者：
DONG Lei;LI Ji-yue;WANG Jun-hui;XIE Ku n;College of Forestry, South China Agricultural University;Institute of Forestry, Chinese Academy of Forestry;
关键词：
Catalpa bungei clones;;drought;;water consumption;;transpiration
摘 要：
For comparing the drought resistant capability of Catalpa bungei clones, 3 clones(clone 004-1, 015-1 and 7080) were chosen for investigation of water consumption and transpiration under water stress. Results showed soil water content of 3 clones decreased significantly with drought. Clone 7080 was about 45.92±1.35% at CK and higher than other 2 clones during the first 10 days. Leaf water potential of 3 clones declined from-0.658±0.057 to-3.178±0.064 MPa at average during drought treatment. Due to low total leaf area, 7080 had a significantly lower water consumption rate than the other 2 clones at CK but not significant under drought. Water consumption rate of clones 004-1 and 015-1 achieved 0 g·h-1 at day 6 whereas 7080 at day 10. Transpirations of 3 clones were consistent reduced under drought. Transpiration diurnal variations of 7080 and 004-1 in CK have two peaks at 12:00 and 14:00 but 015-1 has a lowest point at 14:00 at 1.548±0.104 μmol·m-2s-1. The results indicated that there is significant linear relationship between transpiration(at 10:00) in CK and sum day water consumption. The fitting equation is y=18.798x-81.7(R2=0.9815, p=0.0372). Soil water content(y) and sum water consumption(x) have a significant fitting relationship with an equation y=1.9422x2+9.4586x+69.799(R2=0.9815, p=0.0372) under drought. The rate of soil water content and sum water consumption showed the water use capability of 004-1 and 7080 were better than 015-1. The rate of maximum of day water consumption and average water consumption were stable at 1.38 in CK and severe drought. 7080 had a better water use capability than 015-1 and 004-1 with a stable interval in 1.35-1.39 in this rate.
