毛白杨不同无性系苗木耗水量及其昼夜分配

在苗木生长旺盛时期对19个毛白杨Populus tomentosa无性系当年生苗木耗水特性进行研究,分析比较了无性系间耗水量、耗水速率差异及昼夜分配关系.结果表明:毛白杨不同无性系间耗水量差异极显著,耗水速率差异显著.无性系26、46、BL5、BL8和S86的日耗水量较大,最高的无性系26达(268.1±20.3)g.d-1,无性系30、81、87、1316和TG34的耗水量较小,最低的无性系1316仅(92.0±12.5)g.d-1.总叶面积是引起毛白杨无性系间耗水量差异的重要原因,两者相关系数达0.78,因此在对毛白杨进行速生丰产林营造时应针对无性系确立合理的栽植密度和灌溉量.毛白杨白天耗水速率为112.1~218.8 g.m-2.h-1,其中,无性系26、46、B331和BL2的耗水速率较高,高于181.1 g.m-2.h-1,无性系20、30和87的耗水速率较低,低于119.5 g.m-2.h-1.毛白杨无性系间昼夜耗水量分配稳定,苗木白天耗水量占全天的88.4%~92.6%(平均约90%),白天平均耗水速率与日平均耗水速率比值为1.8.

Water Utilization and Its Distribution in Day and Night in Different Populus tomentosa Clones

Water consumption characteristics, water consumption amount and rate, water distribution of day and night of underyearling seedlings in 19 clones of Populus tomentosa during vigorous growth period were studied.The results showed that different clones of Populus tomentosa had different water consumption amount and rate, clones 46, BL5, BL8 and S86 had larger water consumption amount and clones 26, highest up to (268.1±20.3) g·d~(-1), while clones 30, 81, 87, 1316 and TG34 had smaller water consumption amount, clones 1316, the lowest only (92.0±12.5) g·d~(-1).The main reason for the difference of water consumption amount was total leaf areas variation of the seedlings, and their correlation coefficient was 0.78.Therefore, appropriate planting density and irrigation capacity should be established for different clones in a fast-growing high-yielding plantations.Water consumption rate in day time of Populus tomentosa clones were varied from 112.1 to 218.8 g·m~(-2)·h~(-1).Clone 26, 46, B331 and BL2 had the high water consumption rate (higher than 181.1 g·m~(-2)·h~(-1)), clone 20, 30 and 87 had the low water consumption rate (lower than 119.5 g·m~(-2)·h~(-1)).There was stable distribution of water consumption in day and night.Water consumption amount during the day occupied 88.4% to 92.6% of the whole day (an average about 90%), at the same time, average water consumption rate during the day was 1.8 times to the whole day.