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梭梭(HaloxylonAmmodendronBge,一种C4灌木)苗种植在15升的容器中,给予不同的水分胁迫处理,研究了其水分关系和气体交换特征。结果表明:当土壤水分含量大于11%时,梭梭苗有高的蒸腾量;土壤水分含量低于6%时,苗木就不能从土壤中吸取水分;很好供水的苗木的蒸腾量与潜在蒸发量成线型相关。气体交换测定发现,随着土壤水分含量的下降,造成了不同程度的气孔导度、叶蒸腾强度和光合作用的下降。对同一苗木而言,由于这个地区有高的水气压亏缺(VPD),很好和中度供水的苗木在气孔反应方面有较宽的范围,气孔在决定光合作用方面起着较小的作用,二者没有明显的线型相关关系。虽然水分胁迫使蒸腾速率比光合速率下降的更快,提高了水分利用效率,而较高的蒸发需求增加了蒸腾量,限制了光合作用,但是总的趋势是光合作用和蒸腾强度成线型相关。图6表2参15。
Haloxylon ammodendron Bge, a C4 shrub, was planted in a 15-liter container and subjected to different water stress treatments to study its water relation and gas exchange characteristics. The results showed that Haloxylon ammodendron seedlings had high transpiration when soil moisture content was more than 11%. When soil moisture content was less than 6%, seedlings could not absorb water from soil. The transpiration amount and potential evaporation The amount of linear correlation. Gas exchange assay found that with the decrease of soil moisture content, different degrees of stomatal conductance, leaf transpiration intensity and photosynthesis decline. For the same seedling, because of the high water pressure deficit (VPD) in this area, very good and moderate watering seedlings have a wide range of stomatal responses and stomata play a minor role in determining photosynthesis , There is no obvious linear correlation between the two. Although water stress reduced transpiration rate faster than photosynthetic rate and increased water use efficiency, higher evapotranspiration increased transpiration and restricted photosynthesis, but the general trend was that photosynthesis and transpiration intensity were linearly correlated . Figure 6 Table 2 参 15.