Modelling leaf expansion in a fluctuating environment: are changes in specific leaf area a consequence of changes in expansion rate?
Modelling leaf expansion in a fluctuating environment: are changes in specific leaf area a consequence of changes in expansion rate?
复制标题
DOI：
10.1046/j.1469-8137.1999.00433.x
复制
发表时间：
1999-07
期刊：
影响因子：
9.4
通讯作者：
F. Tardieu;C. Granier;B. Muller
中科院分区：
文献类型：
--
作者：
F. Tardieu;C. Granier;B. Muller
叶片膨胀速率随叶片温度、光子通量密度（PPFD）、蒸发量和土壤水分状况而变化。在大多数模拟模型中，它是每天通过将叶片可利用的碳水化合物量乘以比叶面积（SLA）来计算的。然而，轻度水分亏缺不影响光合作用，也不受叶片快速膨胀期间截获的PPFD减少的影响，叶片的膨胀率大大降低。比叶面积的变化取决于PPFD、土壤水分状况和一天中的时间。当环境条件对扩张速率的抑制作用大于对光合作用的抑制作用时，其增大，反之则减小。因此，独立于植物碳收支来模拟叶片扩张是合适的。从一系列的实验中可以推断出一致的特征，从而提出了叶片膨胀的模型。(1)叶片相对膨胀率和表皮细胞分裂率的时间过程在植物内部和大范围的环境条件下都是保守的，只要持续时间和速率是用热时间表示的。在玉米和向日葵中，叶片的所有区域和植物的所有叶片的最大相对速率是共同的。（ii）在叶片发育的前半期施加水分亏缺或减少截留PPFD只会影响亏缺期的相对膨胀率，但会永久影响绝对膨胀率。相反，如果在叶片自养的快速膨大期施加PPFD，则对叶片的膨大没有影响。（iii）膨胀率与蒸发需求和木质部汁液中ABA的浓度有关，这种关系在田间和实验室条件下都适用。（四）组织扩张和表皮细胞分裂是两个独立的过程，决定了每一次表皮细胞的面积。
Leaf expansion rate varies with leaf temperature, photon flux density (PPFD), evaporative demand and soil water status. In most simulation models, it is calculated every day by multiplying the amount of carbohydrate available to leaves by specific leaf area (SLA). However, leaf expansion rate is considerably reduced by mild water deficits which do not affect photosynthesis, and is not affected by a reduction in the PPFD intercepted during rapid leaf expansion. Specific leaf area undergoes a several-fold variability depending on PPFD, soil water status and time of day. It is increased when environmental conditions have a greater depressive effect on expansion rate than on photosynthesis, and is decreased in the opposite case. It is therefore appropriate to model leaf expansion independently of the plant carbon budget. Consistent characteristics can be deduced from a series of experiments, allowing a model of leaf expansion to be proposed. (i) Time courses of relative leaf expansion rate and of epidermal cell division rate are well conserved within a plant and across a large range of environmental conditions, provided that durations and rates are expressed in thermal time. Maximum relative rates are common to all zones of a leaf and to all leaves of a plant, in maize and sunflower. (ii) A water deficit, or a reduction in intercepted PPFD, imposed in the first half of the period of leaf development affects the relative expansion rate in the deficit only, but permanently affects the absolute expansion rate. In contrast, a reduction in PPFD causes no effect on leaf expansion if imposed in the rapid expansion period when the leaf is autotrophic. (iii) Expansion rate is related to evaporative demand and to the concentration of ABA in the xylem sap with relationships that apply under both field and laboratory conditions. (iv) Tissue expansion and epidermal cell division behave as independent processes which determine epidermal cell area at each time.