Reasearch On Leaf Anatomical Characteristics And Drought Resistance Of Nitraria Tangutorum Bobr. From Six Populations Along The Hexi Corridor

Nitraria tangutorum Bobr. from six populations of different habitats under precipitation gradientfrom east to west along the Hexi corridor, which were collected from WMZ,WMS,ZYL,ZGL,JQJ andJGS,were used as experimental materials. The anatomical structure of leaf were observed underoptical microscope based on the method of paraffin-section.Leaf indexes of Nitraria tangutorum Bobr. were analyzed for the purpose of investigating droughtresistance, including leaf length、width、ratio of length to width、area and thickness, upper and lowerpubescence length、width and density, upper and lower stoma length、width、density and area, upper andlower cuticle thickness, ratio of cuticle thickness to leaf thickness,upper and lower epidermal cellthickness, upper and lower palisade tissue thickness, total of palisade tissue thickness, spongy tissuethickness, ratio of palisade tissue thickness to spongy tissue thickness, ratio of palisade tissue thicknessto leaf thickness, ratio of spongy tissue thickness to leaf thickness,diameter of main vein, diameter oflateral vein, diameter of vascular bundle, diameter of crystal cell, mucilage cell length、width and ratioof length to width, aqueous tissue length、width and ratio of length to width. The result is as follow: Theindexes had different degrees of differences except leaf width, and the indexes such as leaf thicknessand area, upper and lower pubescence length and density, upper and lower stoma length and density,upper epidermal cell thickness, upper and lower palisade tissue thickness, spongy tissue thickness hadsignificant differences among six populations.Twelve xeromorphic indexes were screened by the methods of variance analysis、F and variationcoefficient, and then the relationship of drought resistance was evaluated systematically according tothe method of principal component analysis. The order of drought resistance from six geographicalpopulations was ZYL＞JQJ＞JGS＞WMS＞WMZ＞ZGL.The order means the worse the habitat, thestronger the drought resistance.Combined with variation coefficient and plasticity indexes were compared to explore the adaptiveresponse mechanism of leaf morphology anatomy features to different habitats. The rank of variationcoefficients and plasticity indexes of aggregative indicators from six populations were the same, theorder was JGS＞ZGL＞WMS＞WMZ＞ZYL＞JQJ. It showed that the ecological adaptability ofNitraria tangutorum Bobr. was JGS＞ZGL＞WMS＞WMZ＞ZYL＞JQJ. The variation coefficientand plasticity indexes of palisade tissue, spongy tissue, pubescence of Nitraria tangutorum Bobr. fromsix populations were relatively high, these organizations played a dominant role in response to differentenvironment, the results above may be the adaptive response mechanism of leaf anatomical characteristics to different habitat conditions.