Abstract

Cyperus niveus Retz., also known as snow white sedge grows in dry mountainous regions of Himalayas. Eight populations of C. niveus were collected from different locations in the Salt Range (Punjab) and Kaghan Valley (Khyber Pakhtoonkhwa) to evaluate role of plasticity in adaptability potential through modification in anatomical traits. This species developed xeric anatomical modifications in roots at higher elevations. These were thick endodermis, formation of sclerenchymatous cells outside endodermis, numerous metaxylem vessels, and increased area of central vessel in roots. Roots were more developed in the Kaghan (K) population, showing the largest root radius (774.7 µm), sclerenchymatous cell area (1429.1 µm²), cortical thickness (147.1 µm), and endodermal cell area (7701.4 µm). Stomatal density (21.7 per mm²) was also the highest in the K population. Formation of aerenchymatous cavities, numerous large vascular bundles with wide metaxylem vessels, and large phloem tissue in stems were the prominent features in the K population at the highest elevation (2078 m a.s.l.). All C. niveus populations showed sclerification around and outside of the vascular bundles, larger adaxial epidermal cell area as compared to abaxial epidermal cells, hypostomatal leaves, and increased storage parenchyma in leaves.

摘要

Cyperus niveus Retz.，也被称为雪白莎草，生长在喜马拉雅山的干旱山区。从 Salt Range (Punjab) 和 Kaghan Valley (Khyber Pakhtoonkhwa) 的不同位置收集了8 个C. niveus种群，以评估可塑性通过改变解剖特征在适应性潜力中的作用。该物种在较高海拔处的根部发生了旱生解剖学改变。这些是厚的内皮、在内皮外形成巩膜细胞、大量的后生木质部血管和根部中央血管面积增加。Kaghan (K) 种群的根更发达，根半径最大 (774.7 µm)，巩膜细胞面积 (1429.1 µm ²)、皮质厚度 (147.1 µm) 和内胚层细胞面积 (7701.4 µm)。气孔密度（21.7/mm ²）在钾种群中也是最高的。通气腔的形成、大量具有宽后生木质部血管的大维管束和茎中的大韧皮部组织是最高海拔 (2078 m asl) 钾种群的显着特征。所有C. niveus种群都显示出维管束周围和外部的硬化、与远轴表皮细胞相比更大的近轴表皮细胞面积、下孔叶和叶中储存薄壁组织的增加。