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A mathematical model for photoinhibition of leaf photosynthesis was developed by formalising the assumptions that (1) the rate of photoinhibition is proportional to irradiance; and (2) the rate of recovery, derived from the formulae for a pseudo first-order process, is proportional to the extent of inhibition. The photoinhibition model to calculate initial photo yield is integrated into a photosynthesis-stomatal conductance (g
s) model that combines net photosynthetic rate (P
N), transpiration rate (E), and g
s, and also the leaf energy balance. The model was run to simulate the diurnal courses of P
N, E, g
s, photochemical efficiency, i.e., ratio of intercellular CO2 concentration and CO2 concentration over leaf surface (C
i/C
s), and leaf temperature (T
1) under different irradiances, air temperature, and humidity separately with fixed time courses of others. When midday depression occurred under high temperature, g
s decreased the most and E the least. The duration of midday depression of g
s was the longest and that in E the shortest. E increased with increasing vapour pressure deficit (VPD) initially, but when VPD exceeded a certain value, it decreased with increasing VPD; this was caused by a rapid decrease in g
s. When air temperature exceeded a certain value, an increase in solar irradiance raised T
1 and the degree of midday depression. High solar radiation caused large decrease in initial photon efficiency (). P
N, E, and g
s showed reasonable decreases under conditions causing photoinhibition compared with non-photoinhibition condition under high irradiance. The T
1 under photoinhibition was higher than that under non-photoinhibition conditions, which was evident under high solar irradiance around noon. The decrease in C
i/C
s at midday implies that stomatal closure is a factor causing midday depression of photosynthesis. 相似文献
2.
Transpiration element is included in the integrated stomatal conductance-photosynthesis model by considering gaseous transfer processes, so the present model is capable to simulate the influence of boundary layer conductance. Leuning in his revised Ball' s model replaced relative humidity with VPDs(the vapor pressure deficit from stomatal pore to leaf surface) and thereby made the relation with transpiration more straightforward, and made it possible for the regulation of transpiration and the influence of boundary layer conductance to be integrated into the combined model. If the differences in water vapor and CO2 concentration between leaf and ambient air are considered, VPDs, the evaporative demand, is influenced by stomatal and boundary layer conductance. The physiological responses of photosynthesis, transpiration, and stomatal function, and the changes of intercellular CO2 and water use efficiency to environmental factors, such as wind speed, photon flux density, leaf temperature and ambient CO2, are analyzed. It is shown that ff the boundary layer conductance drops to a level comparable with stomatal conductance, the results of simulation by the model presented here differ significantly from those by the previous model, and, in some cases, are more realistic than the latter. 相似文献
3.
根据水在介质中的流动规律和能量守恒原理,在植物叶片内建立了一个稳态的水传输模型。该模型考虑了气孔复合体内外、共质体与质外体、原生质与细胞壁在水传输上的不同,应用计算机详细地分析和计算了叶内(特别是气孔复合体内)水的传输,得到水势在叶片内近似分布的关系式。应用这些关系式对叶内的水势和水势差作了估计,并对不同解剖特征叶片内的水势差作了比较。 相似文献
4.
本文在已知的气孔运动机理的基础上,对现有的教学模型加以改进,建立了除VPD、CO2和土壤水势的影响外,还能模拟光照和温度等因子对气孔影响的数学模型。在不同组合的环境因子下模拟得到的结果与公认的实验观测结果基本一致。它可以作为研究气孔整体行为的理论框架,也可用于检验多种关于气孔运动的假设。 相似文献
5.
气孔表面上边界层阻力的进一步计算 总被引:1,自引:0,他引:1
把气孔截面看作椭圆面,把每个气孔表面上的边界层区域看作棱柱形区域,在该区域内建立一个三维气体扩散模型。通过应用计算机对模型中的气体扩散方程进行迭代计算,获得比以往更为精确的计算气孔表面上边界层阻力的公式。而该公式与Brown和Escombe的以及Cooke的公式比较,发现在气孔开度变化相当大的范围内,用后面两公式计算气孔外端效应阻力引起的相对误差为10~20%左右。 相似文献
6.
田间小麦叶片气孔对环境因子响应的模拟及叶片水分平衡的计算 总被引:1,自引:0,他引:1
经实测与数据分析得出田间供试小麦叶片气孔对光强、叶温、叶片水势分别作一定形式的响应,据此估算了冠层总气孔导度,进而建立了预测小麦群体蒸腾速率、冠层总气孔导度、叶温、叶片水势等的水分平衡模型。实验表明模型具有较好的预测性。供试小麦叶片一天中可溶性糖含量变化对叶片水势的影响不大。 相似文献
7.
Yong-Tao Wang Shi-Chen Yan Gui-Mei Tang Chao Zhao Tian-Duo Li Yue-Zhi Cui 《Inorganica chimica acta》2011,376(1):492-499
Three new supramolecular complexes based on a 2-(pyrazin-2-yl)-1H-benzimidazole (Hpbi) and a series of Cd(II) salts have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of CdCl2·2.5H2O with Hpbi afforded a one-dimensional chain [Cd(Hpbi)Cl2] (1), which exhibits a three-dimensional (3-D) supramolecular architecture through intermolecular X-H···Cl (X = N and C) hydrogen bonds and π-π stacking interactions. When using CdBr2·4H2O instead of CdCl2·2.5H2O under similar reaction conditions, a bisnuclear complex [Cd(Hpbi)2Br2] (2) is obtained, which obviously exhibits intermolecular X-H···Br (X = N and C) hydrogen bonds and π-π stacking interactions. When CdI2 take place of CdCl2·2.5H2O, a mononuclear complex, [Cd(Hpbi)2I2] (3), is isolated, which shows a 3D supramolecule framework formed by intermolecule hydrogen bonds and π-π packing interactions. Interestingly, the Hpbi ligand exhibits the same coordination modes in complexes 1-3. It is noteworthy that the radius of anions plays an important role in affecting the structures and luminescent intensity of the final products. The TGA for 1-3 have been investigated and discussed in detail. 相似文献
8.
植物镁素营养的研究进展 总被引:1,自引:0,他引:1
总结近些年来有关镁素营养研究应用。详细综述植物对镁的吸收、镁在植物体内的分配与运输、镁的生理作用、植物体内镁与一些元素间的相互作用。 相似文献
9.
营养生长期植物冠根比及其对环境因子的响应 总被引:1,自引:0,他引:1
将光强、温度和土壤水势等环境因子对植物光合、呼吸、同化物运输及生长等生理过程的影响结合起来,并考虑到各生理过程之间的交互作用,建立了一个营养生长期内植物条根比变化及对环境因子综合响应的模型。模型的运行结果表明,该模型与许多实验现象均相吻合。 相似文献
10.
在根组织细胞分裂和细胞体积增大亚过程基础上,建立了一个综合根生长特征参数和环境影响在内的单根伸长的数学模型,同时实验观测了大豆根在不同的环境水势下的生长过程。模型计算结果与实验结果吻合较好。最后利用模型探讨了根伸长对环境因子变化的响应,以及根内水势分布。 相似文献
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