Rodríguez-Calcerrada J, Reich P B, Rosenqvist E, Pardos J A, Cano F J, Aranda I
Unidad de Anatomía, Fisiología y Genética Forestal, Escuela Técnica Superior de Ingenieros de Montes, Universidad Politécnica de Madrid (UPM), Ciudad Universitaria s/n, Madrid, Spain.
Tree Physiol. 2008 May;28(5):761-71. doi: 10.1093/treephys/28.5.761.
We investigated light acclimation in seedlings of the temperate oak Quercus petraea (Matt.) Liebl. and the co-occurring sub-Mediterranean oak Quercus pyrenaica Willd. Seedlings were raised in a greenhouse for 1 year in either 70 (HL) or 5.3% (LL) of ambient irradiance of full sunlight, and, in the following year, subsets of the LL-grown seedlings were transferred to HL either before leaf flushing (LL-HLBF plants) or after full leaf expansion (LL-HLAF plants). Gas exchange, chlorophyll a fluorescence, nitrogen fractions in photosynthetic components and leaf anatomy were examined in leaves of all seedlings 5 months after plants were moved from LL to HL. Differences between species in the acclimation of LL-grown plants to HL were minor. For LL-grown plants in HL, area-based photosynthetic capacity, maximum rate of carboxylation, maximum rate of electron transport and the effective photochemical quantum yield of photosystem II were comparable to those for plants grown solely in HL. A rapid change in nitrogen distribution among photosynthetic components was observed in LL-HLAF plants, which had the highest photosynthetic nitrogen-use efficiency. Increases in mesophyll thickness and dry mass per unit area governed leaf acclimation in LL-HLBF plants, which tended to have less nitrogen in photosynthetic components and a lower assimilation potential per unit of leaf mass or nitrogen than LL-HLAF plants. The data indicate that the phenological state of seedlings modified the acclimatory response of leaf attributes to increased irradiance. Morphological adaptation of leaves of LL-HLBF plants enhanced photosynthetic capacity per unit leaf area, but not per unit leaf dry mass, whereas substantial redistribution of nitrogen among photosynthetic components in leaves of LL-HLAF plants enhanced both mass- and area-based photosynthetic capacity.
我们研究了温带栎树白栎（Quercus petraea (Matt.) Liebl.）和同域分布的亚热带栎树比利牛斯栎（Quercus pyrenaica Willd.）幼苗的光适应情况。幼苗在温室中培养1年，光照强度分别为全日照环境光照的70%（高光，HL）或5.3%（低光，LL）。次年，将低光培养的幼苗的一部分在叶芽萌发前（LL-HLBF植株）或叶片完全展开后（LL-HLAF植株）转移到高光环境。在植株从低光转移到高光5个月后，检测了所有幼苗叶片的气体交换、叶绿素a荧光、光合成分中的氮组分以及叶片解剖结构。低光培养的植株适应高光环境时，两个物种之间的差异较小。对于低光培养后处于高光环境的植株，基于叶面积的光合能力、最大羧化速率、最大电子传递速率以及光系统II的有效光化学量子产率与仅在高光环境下生长的植株相当。在光合氮利用效率最高的LL-HLAF植株中，观察到光合成分之间的氮分布迅速变化。叶肉厚度和单位面积干质量的增加决定了LL-HLBF植株的叶片适应情况，与LL-HLAF植株相比，LL-HLBF植株光合成分中的氮含量往往较少，单位叶质量或氮的同化潜力较低。数据表明，幼苗的物候状态改变了叶片属性对光照增强的适应性反应。LL-HLBF植株叶片的形态适应提高了单位叶面积的光合能力，但未提高单位叶干质量的光合能力，而LL-HLAF植株叶片中光合成分之间大量的氮重新分配提高了基于质量和面积的光合能力。
