Water balance and physiology of hygrophyte in cold regions.

对北海道北部的Sarobetsu沼泽湿地的植被类型、水分生理和水热平衡进行了研究。结果如下：（1）用扩散气孔仪测定了6种植物气孔导度的日变化（Sasapalumata，Moliniopsis japonica，Myrica gale var.tomentosa，Ledum palusire var. divispilosum，Chamaedaphne calyculata，大叶冬青（Ilex crenata var.paldosa）生长在Sasa-湿生植物混合群落中。B）在整个夏季，泥炭土中10 cm深度处的水势接近于零，尽管在干燥天气期间地下水位下降到地表以下40 cm。结果表明，杨梅地下茎直径较大，地下茎直径较大。（4）6种植物的气孔导度与日最大VPD（vapor pressure deficit）呈负相关。当白天VPD较大时，气孔导度维持在较小值，VPD是决定蒸腾的主要因素。

Vegetation type, water physiology and water/heat balances of hygrophytes community were investigated in the Sarobetsu Mire, North Hokkaido. The results are summarized as follows,a) Diurnal changes of stomatal conductance were measured by a diffusion porometer for six species (Sasa palumata, Moliniopsis japonica, Myrica gale var.tomentosa, Ledum palusire var.diversipilosum, Chamaedaphne calyculata, llex crenata var.paldosa) growing in the Sasa-Hygrophytes mixed community.b) Water potential at a depth of 10cm in the peat soil was closed to zero throughout the summer though the ground water level dropped to 40cm below the surface during dry weather.c) The diameter of the subterranean stem of Myrica gale var. tomentosa were decreased and the length of them were extended with rising ground water level in this site.d) Stomatal conductances of the six species were correlated negatively with daily maximum VPD (vapor pressure deficit). When the daytime VPD was large, stomatal conductance maintained at small values and VPD was the main factor to determine the transpiration.