Study On Population Distribution, Morphological Characteristics And Physiological-Biochemical Characteristics Of Dactylis Glomerata In East And West Section Of Tianshan Mountain North Slope

As one important cool-season grass with high value, D. glomerata has many characteristics such as good adaptability, high nutritional value and so on. It is one of the major cultivated species planted in quality artificial grassland in the world. Xinjiang is one of the major areas have rich germplasm resource of D. glomerata, and it is a natural gene pool. In order to protect and make good use of wild plant resources, this study focused on the distribution patterns, distribution regulation, morphological characteristics and physiological-biochemical characteristics of D. glomerata grow in different areas of Tianshan Mountain of Xinjiang. It is aims to reveal the effects of geographical space and habitat on the population distributionin, morphological characteristics and physiological-biochemical characteristics of D. glomerata. The main conclusions were as follows:(1) Population distrbution of wild D. glomerata in different region.The results of species diversity index analysis showed significant differences on distribution of D. glomerata between east and west section of the north of Tianshan Mountain.(2)α diversity index showed a rising and decline trend following the altitude increasing. The β diversity index was between 0.4~0.5 of eastern mountain with altitude at 1800 m, 2200 m and the western mountain with altitude at 1800 m, 2000 m and 2200 m. One negative correlation relationship appeared among species diversity, altitude and aboveground biomass.(3) The interspecific associativity of D. glomerata.The results of total associativity analysis indicated significant positive correlation between the D. glomerata growing with altitude at 1800 m and 2000 m of the east section north slope of Tianshan Mountains. However, one significant negative correlation appeared with the increasing altitude at 2200 m. Associativity index showed that the associativity of species pairs has greater positive association than negative association at altitude of 1800~2200 m of the eastern north slope of Tianshan Mountains. However, the associativity of species pairs has less positive association than negative association the communities with altitude at 1800~2200 m of the west section of Tianshan Mountains. Correlation analysis showed that D. glomerata populations grew at different altitudes showed positive association or negative association with other major dominant plant.(4) Distribution characteristic of wild D. glomerata in different areas.The distribution characteristic of two D. glomerata population was studied by diffusion coefficient and t test methods. The results showed that the distribution types of D. glomerata populations were clumped at both east and west section of the mountain. According to the analytical results of clustered index I, gathered strength k, mean crowding m*, poly-mass index m*/m, Cassie index, the population distribution intensity of D. glomerata at east section mountain was moderate, while the intensity was strong at altitude of 1800 m and 2200 m at western mountain. The pattern size analysis showed the D. glomerata population had obvious peak values at block 4, block 8, block 32 and block 64 at different altitudes.(5) The morphological characteristics of Dactylis glomerata population in different areas.The results of vegetative organs of D. glomerata showed significant differences in the flag leaf length and width, node number, internode length, stem diameter, etc of D. glomerata in different areas, the D. glomerata grow in east section mountain has better morphological characters than the western. Results of reproductive organs character showed: there was a significant difference in the length of the inflorescence, inflorescence width, anther length, spike length, seed length, seed width and grain weight indicators(P <0.05), while no significant difference(P>0.05) in stamen length, anther width, spike width and tiller number. The correlation analysis between vegetative organs and reproductive organs showed that the various forms of index and geographic location, correlation analysis altitude, latitude, longitude and altitude and there was a certain correlation between the various indicators, especially with spikelets showed a significant positive correlation. The result of leaf anatomical structure of D. glomerata showed a significant difference(P>0.05) in Stomatal density, the length of the epidermal cells and the width of the epidermal cells, while no significant difference(P>0.05) in the porosity degree of subsidence of upper and lower epidermis, cuticle thicknessand, length and width of lower epidermis.(6) Physiological-biochemical characteristics of D. glomerata populations in different areas.The result of physiological and biochemical indices for D. glomerata populations of three distribution areas showed there were significant differences in chlorophyll, malondialdehyde(MDA) and POD active substance content in plants between eastern and western mountains. And there were no significant differences in other indexes.(7) Photosynthetic characteristics of D. glomerata populations in different areas.The results of diurnal dynamic changes indicated that the diurnal variation curve of the three regions of D. glomerata decreased first and then increased and then decreased, and reached to peak at 11:00-12:00 am and then decreased. The results of photosynthetically active radiation intensity, transpiration rate, stomatal conductance, leaf temperature and air temperature measurement showed that the peak position of the diurnal variation of all the curves was at 12:00-15:00, then followed a downward trend. The light use efficiency diurnal variation curves of the three regions showed an inverted “V” type, appeared trough at around 15:00 noon. while, the whole day transformation curve of water use efficiency showed a high-low-high-low trend, the light use efficiency and water use efficiency of D. glomerata at three regions was better than the western part of the eastern mountain.Comprehensive analysis of the differences among the Dominant position, distribution, morphological characteristics, physiological and biochemical characteristics and photosynthetic physiological ecology of D. glomerata in different areas of Tianshan Mountain of Xinjiang,so the results could provide the scientific basis for protection strategy, development and utilization of germplasm resources and prediction and evolution of D. glomerata in the future.