CAJ | 학술논문

在对半干旱区3种植物进行生理生态特性测定的基础上,应用两种气孔导度模型进行参数的非线性拟合,BBL模型平均可以解释77.6%的结果,Gao模型平均可以解释59.3%的结果.但Gao模型作为一个机理性的模型,其参数具有明确的物理意义.模型的行为和敏感性分析结果说明,用BBL计算的气孔导度一般大于Gao模型.BBL模型对于干旱胁迫下的土壤水分亏缺没有响应,因而不适合用作干旱半干旱区的植物生理生态学分析和生态系统模拟.而Gao模型可以描述在各种水分条件下植物气孔导度的响应.Gao模型的结果说明,与油松(Pinus tabulaeformis)和中间锦鸡儿(Caragana intermedia)比较,小叶杨(Populus simonii)具有最小的抗旱和耐旱能力,油松具有最好的叶片水平的耐旱和抗旱特性,但其气孔导度对土壤水分的不敏感意味着在干旱条件下维持光合作用的同时,也可能会导致过多的水分损失.中间锦鸡儿具有很强的耐旱性,且其气孔导度对土壤水分的变化敏感,二者相结合,中间锦鸡儿可以在土壤水分条件较好的情况下,维持较大的气孔导度以满足光合作用的需要,但在土壤水分胁迫严重的时候能迅速降低气孔导度以保持土壤水分.
재대반간한구3충식물진행생리생태특성측정적기출상,응용량충기공도도모형진행삼수적비선성의합,BBL모형평균가이해석77.6%적결과,Gao모형평균가이해석59.3%적결과.단Gao모형작위일개궤이성적모형,기삼수구유명학적물리의의.모형적행위화민감성분석결과설명,용BBL계산적기공도도일반대우Gao모형.BBL모형대우간한협박하적토양수분우결몰유향응,인이불괄합용작간한반간한구적식물생리생태학분석화생태계통모의.이Gao모형가이묘술재각충수분조건하식물기공도도적향응.Gao모형적결과설명,여유송(Pinus tabulaeformis)화중간금계인(Caragana intermedia)비교,소협양(Populus simonii)구유최소적항한화내한능력,유송구유최호적협편수평적내한화항한특성,단기기공도도대토양수분적불민감의미착재간한조건하유지광합작용적동시,야가능회도치과다적수분손실.중간금계인구유흔강적내한성,차기기공도도대토양수분적변화민감,이자상결합,중간금계인가이재토양수분조건교호적정황하,유지교대적기공도도이만족광합작용적수요,단재토양수분협박엄중적시후능신속강저기공도도이보지토양수분.
We measured diurnal gas exchange properties of three major species in a semi-arid site, and two stomatal conductance models were then applied to the data. The result indicated that the BBL model and the Gao model could explain on average 77.6 % and 59.3 % of variation in the observed stomatal conductance, respectively. Sensitivity analysis of the models indicated that the BBL model tended to give higher predictions of stomatal conductance than the Gao model. Both models showed similar responses to changes in vapor pressure.The sharp contrast between the two models, however, was that the Gao model responded to changes in soil water stress to different extents. The BBL model coupled with the TJ photosynthesis model was indifferent to increases of soil water stresses, which contradicts concurrent understanding and observations about plant physiology in arid and semiarid regions. Thus the BBL model, even though it provided better explanations of the variations in field stomata data, may not be appropriate for experimental data analysis and ecosystem simulation applications. The analysis using the Gao model indicated that Populus simonii was the least tolerant and resistant to water stresses among the three species studied. Pinus tabulaeformis had both high tolerance and resistance,but stomatal conductance of the pine tree was the least insensitive to changes in soil water stresses. Hence this pine tree may not be good for water conservation under extremely dry conditions. Caragana intermedia, however, had both larger drought tolerance and larger sensitivity to incremental soil water stresses, and thus can provide large stomatal conductance for photosynthesis when soil water stress was low, but reduce water consumption under severe water stresses by decreasing stomatal conductance with increasing soil water stress.