Urban L, Le Roux X, Sinoquet H, Jaffuel S, Jannoyer M
INRA/CIRAD-Flhor, Station de Bassin-Martin, BP 180, 97455 Saint-Pierre, France.
Tree Physiol. 2003 Apr;23(5):289-300. doi: 10.1093/treephys/23.5.289.
Variations in leaf nitrogen concentration per unit mass (Nm) and per unit area (Na), mass-to-area ratio (Ma), total nonstructural carbohydrates (Ta), and photosynthetic capacity (maximum carboxylation rate, electron transport capacity, rate of phosphate release in triose phosphate utilization and dark respiration rate) were studied within the digitized crowns of two 3-year-old mango trees (Mangifera indica L.) on La Réunion Island. Additional measurements of Nm, Na, Ma, Ta and photosynthetic capacities were performed on young, fully expanded leaves of 11-year-old mango trees. Leaves of similar gap fractions were taken far from and close to developing fruits. Unlike Nm, both Na and Ta were linearly correlated to gap fraction. Similar relationships were found for all leaves whatever their age and origin, except for Ta, for which we found a significant tree effect. Photosynthetic capacity was nonlinearly correlated to Na, and a unique relationship was obtained for all types of leaves. Photosynthetic acclimation to light was mainly driven by changes in Ma, but allocation of total leaf N between the different photosynthetic functions also played a substantial role in acclimation to the lowest irradiances. Leaves close to developing fruits exhibited a higher photosynthetic capacity than other leaves, but similar Ta. Our data suggest that Ta does not control photosynthetic capacity in mango leaves. We used the data to parameterize a biochemically based model of photosynthesis and an empirical stomatal conductance model, allowing accurate predictions of net photosynthesis of leaves in field-grown mango trees.
在留尼汪岛上，对两棵3岁芒果树（芒果属印度种）数字化树冠内单位质量（Nm）和单位面积（Na）的叶片氮浓度、质量面积比（Ma）、总非结构性碳水化合物（Ta）以及光合能力（最大羧化速率、电子传递能力、磷酸丙糖利用中磷释放速率和暗呼吸速率）的变化进行了研究。对11岁芒果树的幼嫩、完全展开的叶片进行了Nm、Na、Ma、Ta和光合能力的额外测量。从远离和靠近发育中果实的部位选取了间隙率相似的叶片。与Nm不同，Na和Ta都与间隙率呈线性相关。无论叶片年龄和来源如何，所有叶片都呈现出相似的关系，但Ta除外，我们发现Ta存在显著的树体效应。光合能力与Na呈非线性相关，并且所有类型的叶片都呈现出独特的关系。光合对光的适应主要由Ma的变化驱动，但总叶氮在不同光合功能之间的分配在对最低辐照度的适应中也起到了重要作用。靠近发育中果实的叶片比其他叶片具有更高的光合能力，但Ta相似。我们的数据表明，Ta并不控制芒果叶片的光合能力。我们利用这些数据对基于生化的光合作用模型和经验气孔导度模型进行参数化，从而能够准确预测田间种植芒果树叶片的净光合作用。
