| Grassland ecological system is an important type of terrestrial ecosystem. Because natural disaster or man-made interference increased more heavily and natural grassland degradation become more and more serious. In Songnen grassland degradation and restoring succession process, the quantity change of Leymus chinensis and Kalimeris integrifolia population has an important telltale effect. By the natural grassland different proportion of L. chinensis and K. integrifolia population for object, after the observation investigation throughout the growing season, the study analysed the quantity and biomass dynamics and age structure on L. chinensis and K. integrifolia populations. It revealed degradation grassland restoring process collaborative change rules of two populations and provided theoretical guidance for the restoration of degradation grassland ecosystem. Results show that:L. chinensis population tillers of different succession community was constructed by 3-4 age classes. 1 age tillers were the most important roll and can reach 188.0-226.4 plants/m2 and the tillers decreased by the increase trends of the age grade, the proportion of 4a least, only 0.8-4.0 plants/m2. L. chinensis population represented an increasing age structure. K. integrifolia populations was constructed by 3 age classes, representing an stable age structure, with 2 age constituted of major advantages, at least third age 35.2-71.2 plants/m2. L. chinensis young tillering strains in different succession community of initial, middle and late growing season series, all is developing very quickly throughout the growing season. L. chinensis population within the renewal speed of the updated faster than K. integrifolia population. The tiller biomass in different succession community was the same as the tiller number .The tiller biomass and number of L. chinensis and K. integrifolia in the growing season have the same change tendency.The L. chinensis cumulative root length of different succession community was constructed by four age . The largest 2 age was the most important, the average length of 1231.5-2045.1cm/m2, the next 3a and the minimum 4a for an average of 545.9-1433.4cm/m2, representing an stable age structure. 1 age in new roots at the end of the growing season has increased and the trend of 2 age rhizome is smooth in the growing season, 3 and 4 age has no obvious rule. Age structure of L. chinensis roots biomass allocation consistented of the accumulation rhizome length. The largest 2a was 11.4-13.4g/m2. The K. integrifolia population root biomass by 3 age formation constitute, 2 age level of absolute superiority, reach 6.4-15.3 g/m2, 1 a and 3a next, presenting an stable age structure. In the growing season end, L. chinensis new roots biomass has increased and K. integrifolia old root biomass increased. With succession time increasing, the advantage of L. chinensis root storage capabilities will be reflected.L. chinensis vegetative buds of different succession community had 4-5 age composition with zero age of dominant number 247.2-737.6a/m2, the number of buds reduced with age increasing, the least 4 age, representing a growth age structure. K. integrifolia vegetative buds was constructed by 3 age classes and performanced an stable age structure for 2 a > 1 a>3 a. 0a and 1a buds of L. chinensis and K. integrifolia population were increasing in the end of the growing season, L. chinensis population nutrition fertility is higher.K. integrifolia tillering strains quantity, tillering plant biomass and underground component biomass tended to decline as L. chinensis relevant indicators. The tiller number and biomass from July to October chieved significant level (p<0.05). As degradation grassland restoration succession deepening, L. chinensis population will show good growth state and replace K. integrifolia by a major dominant population in Songnen plain. |
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