唐古特白刺叶片形态结构的地域环境分异

Regional and environmental differentiation of leaf morphology and anatomical structure of Nitraria tangutorum

为探讨不同地域环境唐古特白刺叶片在形态、结构上形成的分异规律,本研究以分布于暖温型荒漠草原亚带(W)、暖温型草原化荒漠亚带(D)、暖温型典型荒漠亚带(M)3个地域9个生境的白刺为研究对象,采用石蜡切片法比较分析叶片形态、结构。结果表明:(1)采自荒漠化草原的白刺叶片长度、长宽比、厚度均最大,典型荒漠的叶片各指标最低。荒漠化草原的白刺叶片上、下表皮、海绵组织最厚;典型荒漠的叶片最薄。草原化荒漠的白刺叶片上、下栅栏组织最厚;典型荒漠的最薄;草原化荒漠的白刺栅栏组织与海绵组织比最大,荒漠化草原的最小。(2)9个生境中白刺叶片形态结构指标具有显著差异,其中,WBL白刺叶片长、宽、厚最大;DGD叶片长宽比最大;DTD叶片上、下表皮厚度,上、下栅栏组织厚度,海绵组织厚度均为最大;MGD叶片栅栏组织与海绵组织比最大。(3)白刺受到干旱胁迫和盐胁迫后,同化组织中出现粘液细胞以增加渗透压,并且粘液细胞数量随胁迫加剧而增加;海绵组织特化为贮水组织或体现出明显的栅栏化。

To explore the differentiation of leaf morphology and anatomical structure of Nitraria tangutorum due to the regional and environmental differences, in this study, the morphology and structure of the Nitraria tangutorum leaves that were collected from 9 habitats in 3 different climate regions, where locate distributed in desert steppe, steppe desert and typical desert, respectively were comparatively analyzed by paraffin section. The results showed that:(1) The leaf length, length-width ratio and thickness of N. tangutorum collected from the desertification steppe are the largest, while those from the typical desert are the lowest. The upper and lower epidermis and spongy tissue collected from desertification grassland are the thickest, while those from typical deserts are the thinnest. The upper and lower palisade tissues are the thickest collected from steppe desert;while the thinnest is from typical desert. The largest palisade-spongy tissue ratio is from steppe desert, and the smallest is from desertification steppe.(2) The morphology and anatomical structure indexes of N. tangutorum leaves in 9 habitats show significant difference. Among them, leaves from WBL have the largest length, width and thickness;leaves from DGD have the largest length-width ratio;leaves from DTD have the largest thickness of upper and lower epidermis, upper and lower palisade tissue, sponge tissue, and those from MGD have the largest palisade-sponge ratio.(3) With the drought and salt stress, mucus cells appear in the assimilation tissues to increase osmotic pressure, and the number of mucus cells depend up on the stress degree;sponge tissue is specialized as water storage tissue or shows obvious palisade.