Sundri (Heritiera fomes Buch.-Ham.) is an evergreen mangrove tree species found abundantly in the freshwater zone of Sundarbans, Bangladesh and scattered in moderate or strong saline zones of the forest. H. fomes grows well in top canopy having full sunlight and even in full shade under the canopy. This study presents the plasticity of leaf morphological and anatomical characteristics in H. fomes due to variation of light intensity at different canopy depths and of salinity in different saline zones of Sundarbans. This study was conducted in two steps, firstly the light intensity and leaf phenotypic variations at different canopy depths (one-meter interval) in the fresh water zone of Sundarbans, secondly the leaf phenotypic variations in three saline zones having variable light environment at different canopy positions (top, middle and bottom) in each zone. Leaf samples were collected from three different salinity zones and each canopy positions and various morphological and anatomical characteristics were quantified. A wide range of variations were observed in the leaf parameters measured among the salinity zones of the Sundarbans and the canopy positions. The canopy of H. fomes showed an exponentially decreasing light gradient. Leaf plasticity index (PI) of all the parameters was developed for the salinity zones and the canopy positions of the Sundarbans. The ordination plots (PCA) suggested clear morphological and anatomical shift of the samples collected from different saline zones and canopy positions showing relationship to light and salt stresses in natural environment. Our results provide clear evidence on plastic strategy of H. fomes against salinity and light gradients in the Sundarbans.

Sundri（Heritiera fomes Buch.-Ham。）是一种常绿的红树林树种，在孟加拉国Sundarbans的淡水区中大量发现，并散布在森林的中度或强盐度地区。H. fomes在充满阳光的顶棚中生长良好，甚至在顶棚下也充满阴影。这项研究提出了叶形态的可塑性和解剖特点H.腐由于在Sundarbans的不同冠层深度和盐分不同地区的光强度变化。这项研究分两个步骤进行，首先是桑达班斯淡水区不同冠层深度（一米间隔）处的光强度和叶片表型变化，其次是在不同冠层光环境可变的三个盐渍区中叶片表型变化。每个区域中的位置（顶部，中间和底部）。从三个不同的盐度区收集叶片样品，并对每个冠层的位置以及各种形态和解剖特征进行定量。在Sundarbans盐度区和树冠位置之间测得的叶片参数中观察到了各种各样的变化。H. fomes的冠层呈现出指数递减的光梯度。所有参数的叶片可塑性指数（PI）是针对苏达班盐分带和冠层位置而制定的。排序图（PCA）表明，从不同盐分区域和树冠位置收集的样品的形态和解剖学变化明显，显示出与自然环境中的光和盐胁迫相关。我们的研究结果提供了清晰的证据，证明了H. fomes对抗Sundarbans中盐度和光梯度的塑性策略。