摘要
通过对沙棘叶片的蒸腾速率、气孔导度及其相应环境因子的测定 ,探讨黄土丘陵区安塞人工沙棘林的水分生理生态特征。结果表明 :沙棘蒸腾速率和气孔导度具明显的日变化 ,两者的变化趋势相似 ,5、7月份日变化曲线呈单峰型 ,6、8、9月份日变化曲线呈双峰型 ;在生长季 ( 5～ 9月份 )中 7月份蒸腾速率最大 ,5、9月份较小 ,5月份 ( 0 .390 0 g/( g· h) )仅为7月份 ( 0 .935 0 g/( g· h) )的 4 1 .95 % ;沙棘林在生长季的蒸腾耗水量为 2 5 7.5 6 mm(占同期降雨量的 6 3% ) ,与降雨量间有极显著的相关关系。沙棘林的蒸腾耗水量在降雨量不同的月份有明显的差异 ,9月份 (降雨量为 4 3.2 mm)的蒸腾耗水量为 7月份 (降雨量为 1 30 .1 mm)的 2 5 .9%。黄土丘陵区安塞的环境条件基本满足沙棘生长的要求 。
To explore water physiologically ecological characteristics of artificial Hippophae rhamnoides L. stand, it measured transpiration intensity and stomatal conductance in leaf of Hippophae rhamnoides L. and environmental factors, which aimed at providing scientific basis for drought-forestation, management and comprehensive evaluation after forestation. Hippophae rhamnoides L. stand selected as sampling plots was planted at Ansai station during 1993~1995, with a plant and row spacing of 1.5m×2m. In the experiment, standard plants of Hippophae rhamnoides L. were selected as measuring plant, vital measurements were made by selected apricus, mature, and sound leaves of middle part of standard plant. In May ~ September month of growth season of 1998, measurement was conducted to diurnal change of transpiration intensity of Hippophae rhamnoides L., stomatal conductance, intercellular CO 2 concentration and environmental factors. Average value and standard deviation were made by statistical analysis of the measured data. To calculate water consumption through transpiration of Hippophae rhamnoides L. woodland, unit of transpiration rate was changed into gH 2O/(g·h) in the light of the ratio of fresh weight of leaves to leaf area. Water consumption through transpiration of Hippophae rhamnoides L. was calculated by the following formula: W= E×b×h×10 -3. Regular observation was made to growth of Hippophae rhamnoides L., soil moisture and precipitation of woodland. Computer then analyzed the data. Results showed: (1) Transpiration intensity had obvious diurnal change, it had different change in different month. Diurnal change of transpiration intensity assumed single-peak pattern in May and July, peak-value appearing around 12h. Diurnal change of transpiration intensity assumed bimodal pattern in June, August and September, with the first peak-value appearing at 10~12h ,and the second one at 14~16h. The appearance time and size of two-peak-value had difference to some degree in different month. According to the characteristics of transpiration intensity of Hippophae rhamnoides L., diurnal change of transpiration intensity assumed single-peak or bimodal pattern, transpiration intensity was usually more stable. Therefore, it could be understood that Hippophae rhamnoides L. had certain adaptability to drought environment. These belonged to the characteristics of transpiration of mesophyte. (2) Stomatal conductance of Hippophae rhamnoides L. had obvious diurnal change. It had differently diurnal change in different months . In June, August and September, with illumination gradually enhancing, stoma expanded under the influence of light, stomatal conductance gradually increased, and reaching its peak-value around 9h, with an average of 289.02μmol/(m 2·s). After that, vapor pressure deficit between extra-foliage and intralobar part enlarged because the temperature went up, under the condition of strong transpiration, the decrease of leaf water potential led to the decrease of stomatal conductance. It resulted in the decrease of transpiration, which made water contents of mesophyllous cell of leaves of Hippophae rhamnoides L. restored to certain degree in afternoon. It brought about the ascent of stomatal conductance, and thus the second peak-value of the day appeared around 15h, with an average of 109.00μmol/(m 2·s). After this, with illumination decreasing, stomatal conductance gradually decreased. In May and July, diurnal change of stomatal conductance of Hippophae rhamnoides\% L. assumed single-peak pattern, and reaching its peak-value around 9h. Daily average of stomatal conductance of Hippophae rhamnoides L. was 159.00μmol/(m 2·s), with a total change range of 73.9~363.9μmol/(m 2·s). Appearance time and size of two-peak-value of stomatal conductance in a day had close correlation with weather factors of the day, endophytic water condition and intercellular CO 2 concentration. Transpiration intensity and stomatal conductance of Hippophae rhamnoides L. had a similar diurnal change, which showed transpir
出处
《生态学报》
CAS
CSCD
北大核心
2001年第12期2141-2146,共6页
Acta Ecologica Sinica
基金
国家科技部中俄国际合作资助项目
水利部"94 8"引进资助项目 ( 975 1 5 4 )
江苏省计经委项目
关键词
沙棘
蒸腾速率
气孔导度
水分生态
人工林
黄土丘陵区
Hippophae rhamnoides L.
transpiration intensity
stomatal conductance
water ecology
