Aphalo P J, Gibson D, Di Benedetto A H
Departamento de Ecología, Facultad de Agronomia, Universidad de Buenos Aires, 1417 Buenos Aires, Argentina.
New Phytol. 1991 Mar;117(3):461-471. doi: 10.1111/j.1469-8137.1991.tb00010.x.
The response of Fuchsia magellanica Lam. - a shade-tolerant perennial - to white light photon flux density and end-of-day red and far-red light irradiation was studied to evaluate the role that different morphological and functional alterations play in whole-plant acclimation to shade. The estimated relative growth rate of plants growing under a photon flux density of 30μmol m s was 71 % of that of those growing under 450μmol m s . The proportion of total dry weight allocated to shoots was higher in low light plants, but the proportion of shoot dry weight allocated to leaf blades was not affected by any of the treatments. The estimated relative growth rate, specific leaf area and leaf conductance were not affected by end-of-day irradiation. In low light plants the specific leaf area was higher, and at saturating photon flux density photosynthesis was lower on a leaf area basis, but was not on a leaf dry weight basis. Dark respiration was higher in high light plants when expressed on an area basis, but not when expressed on a dry weight basis. During the normal photoperiod, leaf conductance measured in darkness was higher in high light plants than in low light ones, which is consistent with the higher stomatal density observed in these plants. The cross-sectional area of the petioles was slightly reduced in low light in spite of a large increase in the area of individual leaves. Low irradiance affected the display of leaves, decreased leaf thickness and increased chlorophyll content per unit dry weight. End-of-day far-red resulted in plants with more erect branches. Both low photon flux density and far-red enhanced internode elongation. The effect of end-of-day irradiations was bigger in low light than in high light, which is the opposite to what is observed in shade-avoiders. The relatively small difference in mean growth rate can be explained by changes in specific leaf area, shoot: root dry weight partition ratio, and by the shape of the photosynthetic light response curve. However when comparing photosynthetic rates on a dry weight basis low light plants do not seem to be at a disadvantage under high light.
研究了耐阴多年生植物智利 fuchsia（Fuchsia magellanica Lam.）对白光光子通量密度以及日终红光和远红光照射的响应，以评估不同形态和功能变化在整株植物适应遮荫过程中所起的作用。在光子通量密度为30μmol m⁻² s⁻¹ 下生长的植物，其估计相对生长速率是在450μmol m⁻² s⁻¹ 下生长植物的71%。分配到地上部分的总干重比例在弱光植物中较高，但分配到叶片的地上部分干重比例不受任何处理的影响。估计相对生长速率、比叶面积和叶片导度不受日终照射的影响。在弱光植物中比叶面积较高，在饱和光子通量密度下，以叶面积为基础光合作用较低，但以叶干重为基础则不然。以面积为基础表示时，高光植物的暗呼吸较高，但以干重为基础表示时则不然。在正常光周期期间，高光植物在黑暗中测得的叶片导度高于弱光植物，这与这些植物中观察到的较高气孔密度一致。尽管单叶面积大幅增加，但弱光下叶柄的横截面积略有减小。低光照影响叶片的展示，降低叶片厚度并增加单位干重的叶绿素含量。日终远红光导致植物的枝条更直立。低光子通量密度和远红光都增强了节间伸长。日终照射在弱光下的影响比在强光下更大，这与避荫植物中观察到的情况相反。平均生长速率的相对较小差异可以通过比叶面积、地上部分：根干重分配比的变化以及光合光响应曲线的形状来解释。然而，当以干重为基础比较光合速率时，弱光植物在高光下似乎并不处于劣势。
