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两种南亚热带林下灌木叶片水分特性的比较研究 被引量:1

COMPARISON ON LEAF-WATER-RELATION OF TWO SHRUB SPECIES IN A SOUTH CHINA
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摘要 鼎湖山南亚热带针叶一阔叶混交林下灌木桃金娘和三叉苦叶片气孔导度的日进程多为单峰形。一天中出现气孔导度高值的时间随季节而异,从3月到10月逐渐提前。夏季气孔导度最大,冬季最小。8月份生长于坡顶群落中的两种灌木叶片气孔出现“午睡”现象。不同生长地点中,桃金娘的气孔导度均明显高于三叉苦. 叶片水势从早晨起逐渐降低,中午达最低值,随后有所回升。3月和8月的水势较高,12月水势最低。水势与气孔导度间呈双曲线关系。压力一体积曲线的测定表明叶片水势低值时仍能维持正膨压。 The water relations of leaves for two understory shrubs, Rhodomyrtus tomentosa and Evodia lepta in a south subtropical forest were studied. The experiment was conducted at two sites in Ding Hu Shan mountain, Guangdong Province. The 'open site' was on the top of back-hill near the office of Reserve Station,and the 'middle site' was downwarded about 30m on the same hill. Stomatal conductance and water potential were measured by stable porometer(Li-cor 1600) and PMS pressure chamber respectively. Water potential components were calculated from pressure-volume curves.The daily courses of stomatal conductance in two plants from local time 7:00 to 17:00 showed a pattern of single peak. The time with maximum stomatal conductance in a day varied depending on seasons, it shifted to an earlier time from March to October. The highest average stomatal conductance was found in summer, and the lowest in winter. A midday depression of stomatal conductance was observed at the open site in August. In all cases at these two sites, and in nursery site, R. tomentosa had a higher stomatal conductance than E lepta.Water potential went down from dawn and reached its minimum at noon,then raised back again in the evening. The trend of high water potential in March and August and low one in December was in consistent with the change of wet and dry season. Diurnal and seasonal patterns of water potential were not different between the two shrubs, but R. tomentosa possessed relatively higher water potential at dawn and midday than E. lepta in dry season.The relationship between stomatal conductance and leaf water potential was regarded as a hyperbola for this two plants. In August, the minimum water potential was still kept over the osmotic potential at zero turgor. No significant difference in the capacity of osmotic adjustment was found between the two species although they showed a different stomatal conductance pattern.
出处 《植物生态学与地植物学学报》 CSCD 北大核心 1993年第2期110-119,共10页
关键词 叶片水势 桃金娘 三叉苦 灌木 Stomatal conductance Leaf water potential Shrub Rhodomyrtus tomentosa Evodia lepta
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  • 1J. R. Ehleringer,C. B. Field,Zhi-fang Lin,Chun-yen Kuo. Leaf carbon isotope and mineral composition in subtropical plants along an irradiance cline[J] 1986,Oecologia(4):520~526
  • 2J. R. Ehleringer,O. Bj?rkman. Pubescence and leaf spectral characteristics in a desert shrub, Encelia farinosa[J] 1978,Oecologia(2):151~162

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