Variations In Leaf Anatomy Of Larix Gmelinii In Different Resourse And Reflect Adaptation To Climate Changes

Larix gmelinii Rupr. as the dominant species of the boreal forest in China has the characteristics of strong adaptability,such as fast growth,short growth cycle, cold tolerance and its wide distribution.Leaf anatomy, being susceptible to environmental factors, is closely related to physiological functions of the leaf, and also reflects responses and adaptation of the tree to environmental changes. However, it is difficult to distinguish short-term responses of leaf anatomy and physiology from their potential long-term adaptation to climate changes in field. Get the anatomical characters of Larix gmelinii Rupr. leaf in different areas, preliminary analysis of the leading ecological factors of affecting its change, provide basic datas to further reveal the ecological countermeasures for different regional distribution Dahurian larch in response to climate change. We conducted a common garden experiment that included six provenances of Larix gmelinii Rupr. with different climate and site conditions and the youth larchs from four latitudes, three replicate trees each provenance. We measured parameters of leaf anatomical properties (i.e., total leaf thickness, epidermis cells, mesophyll cells, transmission tissue cells, vascular cells, and endothelial cells) and photosynthetic physiology (i.e., photosynthetic capacity [Pmax-a], stomatal conductance [gs], water use efficiency [WUE]) in order to address whether leaf anatomical structure adapts to climate changes and consequently results in physiological adaptation.The results were as follows:(1) The results showed that the thickness of epidermis cells, mesophyll cells, transmission tissue cells, vascular cells and endothelial cells, and the total thickness of the needles differed significantly among the provenances (P<0.05). The blade structure characteristics thickness difference in the proportion of the total thickness of the blade, the thickness of the mesophyll cells (LCD) the largest proportion of the average fluctuations in the range of38.4to43.3%.(2) The thickness of mesophyll cells was positively correlated (P<0.05) with Pmax-a, gs, or WUE. Zhongyangzhan and Tahe provenance blade has a higher Pmax-a, gs, or WUE,Wuyiling and Tahe provenance has a lower measured physiological characteristic values, the mesophyll cell thickness and provenances with the determination of physiologicalfeature is higher than the leaf thickness and vascular bundle thickness.(3) We concluded that Dailing, Heihe, Songling three kinds of the thickness of the blade, the thickness of the mesophyll cells, vascular bundle thickness three indicators trend manifested in different months, Tahe provenance opposite trend. The source blade thickness, inner cortex, transmission organizations and vascular bundles in July and September were significantly different. August was no significant difference. (4) The thickness of the mesophyll cells, epidermal thickness, the total thickness of the blade and the the mesophyll cell thickness and the thickness of the epidermal cells proportion of the total thickness of the blade with the provenance situ aridity index was a positive linear relationship. With the increase in provenance situ dry leaf thickness (LD), the mesophyll cell thickness (LCD) and the thickness of the epidermal cells (LPD) were significantly increased, and the LCD and the LPD in LD proportion with the increase in AI increases significantly.