Study On Genetic Diversity, Physiological Characteristics And Slop Protection Properties Of Human Eremochloa Ophiuroides

This paper studied genetic diversity among 30 wild Eremochloa ophiuroides germplasm resources collected from 12 places in Hunan province by using Inter-Simple Sequence Repeat (ISSR) markers and analyzing morphological characteristics. The results got as follows:(1) Big variation of 30 Eremochloa ophiuroides took place on 12 morphological indexes, among which the variations of root depth, leaf area, length of leaves-hair, stem color and leaf color achieved above 20 percent. (2) The correlation analysis on morphological indexes results got indicated that the height of leaf layer has highly significant positive correlation or negative correlation with seven morphological indexes such as leaf length, prostrate stem diameter, leaf area, lamellar seta, stipites length of erect stem, stipites length of creeping stem and leaf color. The r value range was from -0.791 to 0.803. Leaf color has highly significant positive correlation or negative correlation with leaf length, stipites length of erect stem, stipites length of creeping stem, the diameter of creeping stem and leaf area. R value was between -0.889 and 0.793. (3)The cluster analysis on morphology indexes of 30 materials tested indicated that in the Euclidean distance of 8.445,30 germplasm resources tested were possible to be divided into three shape types, namely normal, tall and big, and dwarf form. (4) Considering both leaf form and green period, wild Eremochloa ophiuroides germplasm resources picked from Weicheng, a village in Linxiang county of Yueyang city, were quite suited to Changsha as lawn grass. (5)Basing on the previous studies, a set of simple, rapid and accurate techniques have been explored for Hunan wild Eremochloa ophiuroides DNA extraction and purification, and an ISSR-PCR Reaction System suit for Eremochloa ophiuroides has been established. (6)The study took a genetic diversity test on 30 Hunan wild Eremochloa ophiuroides germplasm resources by using seven polymorphic ISSR primers picked from 70 ISSR primers. The test showed that Hunan wild Eremochloa ophiuroides germplasm resources have a rich hereditary change. 126 bands may be analyzed were found, among which, polymorphic bands were 123. General polymorphic sites accounted for 97.62%. In single share material level, 1=0.0878, H=0.1302. In community level I=0.0878, H=0.1302. (7)Nei heredity multiplicity analysis indicated that a certain degree heredity differentiation (GST =0.5434) existed among 12 communities. The lowest heredity diversity levels appeared in Hengyang, Loudi, Shaoyang Eremochloa ophiuroides community. While the highest heredity diversity levels appeared in Yongzhou Eremochloa ophiuroides community. (8) The variation range of Nei's heredity distance (D) among 30 Hunan wild Eremochloa ophiuroides communities was from 0.0274 to 0.1942. According to Nei's heredity distance got, this study constructed heredity relations cluster charts of 12 communities by using UPGMA. At 0.12 of Euclidean distance,12 communities could be divided into 6 kinds. The division group has obvious relations with geographic distribution. Since Huaihua Eremochloa ophiuroides community was closely related to Jishou Eremochloa ophiuroides community, they were gathered together in the same place firstly. Shaoyang Eremochloa ophiuroides community and Hengyang Eremochloa ophiuroides community's heredity was far away from each other. (9)The study took cluster analysis by NTSYS-pc2.10 software to 30 Hunan wild Eremochloa ophiuroides germplasm resources using data got from ISSR markers. The analysis results indicated the materials would be divided into 8 big types when similarity factor 0.780 was threshold value. Communities divided according to ISSR heredity similarity coefficient have certain relations with geographic distribution. This was consistent with the principal components analysis result. (10) Inter-Simple Sequence Repeat (ISSR) markers and morphological characteristics told us genetic diversity of Hunan wild Eremochloa ophiuroides from different levels. The two methods could not be substituted for another. Only the integration analysis of the two ways, could we comprehensively revealed the genetic nature of Hunan wild Eremochloa ophiuroides.Physiological characteristics refer to a comprehensive performance of plants' life activity law and mechanism in a variety of environmental conditions. In this study, Linxiang E22 Eremochloa ophiuroides in Yueyang city was taken as research object. Three kinds of warm-season turfgrasses, local Changsha Cynodon dactylon, Qingdao Zoysia sinica in Shandong province and American Paspalum notatum were selected as contrast. External form, physical activity, photosynthetic characteristics, drought resistance, salt resistance and cold hardiness of turfgrasses were evaluated. The results indicated:(1) Under drought stress, the leaves of Eremochloa ophiuroides has a lower membrane permeability, proline accumulated long and accumulation was large, chlorophyll content decreased slowly and decline range was small, water deficit MDA increased slowly and small. A comprehensive analysis of physiological indicators of four warm-season turfgrasses was made by fuzzy subordination method. Centipedegrass drought resistance was weaker than bermudagrass, zoysiagrass, and Bahiagrass. (2) As salt stress to Eremochloa increased, the dry weights of roots, stem, and leaf were trending downward. With the extension of processing time and increasingly higher salt concentration, plants'normal growth was shortened, wilting degree and number of deaths gradually increased. While leaf color turned from green to yellow or brown and leaf quality from soft to hard. Among five physiological parameters, leaf MDA content and relative electrical conductivity gradually increased, total content of chlorophyll decreased, proline content and catalase activity was first increased and then decreased. Statistical analysis between salt tolerance index and salt concentration showed that linear regression relationship existed between salt tolerance index and salt concentration. A series of physiological reactions occurred in the leaves under salt stress showed that proline, relative conductivity and MDA content and catalase activity were four best physiological parameters to indicate salt tolerance. (3) In natural cooling process, the period of Eremochloa ophiuroides turning withered was 73 days. The membrane electrolyte leakage was 97%. Superoxide dismutase activity in the rate of increase was less than the other three warm-season turf grasses. Soluble sugar content was 28.79%. Proline content reached extreme peak 4.48 mg/g in 12-hour under cold stress. Basing on field green stage observation and various physiological analysis, Eremochloa ophiuroides's cold hardiness was weak compare to the other three warm-season turf grasses. (4) Eremochloa ophiuroides'Diurnal variation of photosynthetic rate was typical "bimodal", that is to say it has a morning and afternoon peaks, and noon "nap" phenomenon. Seasonal change of photosynthetic rate was "single-peak-type" trend. Eremochloa ophiuroides'photosynthetic light saturation point (LSP) and light compensation point (LCP) were 1375 and 46.25μmol·m-2·s-1 respectively. CO2 compensation point was 21.91μl·L-1 and CO2 saturation point was 1810μl·L-1. Diurnal variation trend of net photosynthetic rate was obviously a "single peak" and in a variety of shading, the annual average photosynthetic rate was lower than the control level. However, the peak of Pn in one year appeared in September, which was the same with control. It indicated that the shade would reduce turfgrass growth rate, but it would not change its growth rhythm. Chla/chlb value reflected the Eremochloa ophiuroides has good ability to adapt to shade.The slope has a significant effect on lawn grass maximum interception amount, and through the synthetic analysis on the four warm-season lawn grass under the conditions of different slopes, the stems and leaves interception effect of the four lawn grass kind arranged in order as follows:Paspalum notatum> Cynodon dactylon> Eremochloa ophiuroides> Zoysia sinica.The maximum compressive stress of Eremochloa ophiuroides'root system was in direct linear proportional to the root diameter while the tensile strength was inversely proportional to the root diameter. The average maximum compressive stress of the four warm-season lawn grass's root system lists in order as follows:Paspalum notatum 11.06 N> Eremochloa ophiuroides 9.05 N> Zoysia sinica 5.92 N> Cynodon dactylon 5.06 N, and the average tensile strength lists in order as follows:Paspalum notatum 34.64 mPa> Eremochloa ophiuroides 27.58 mPa> Cynodon dactylon 26.31 mPa> Zoysia sinica 22.82 mPa.Eremochloa ophiuroides'soil shear strength was higher than the control of Zoysia sinica and Cynodon dactylon, but less than Paspalum notatum. Turfgrass roots significantly increased the maximum shear strength of soil. The weighted average method to conduct a comprehensive evaluation and analysis was used. Results showed that in a natural state (vertical pressure 10kPa) shear strength of soil arranged in order as follows:Paspalum notatum> Eremochloa ophiuroides>Cynodon dactylon> Zoysia sinica.