Effects Of Mowing Treatment On Physiological Integration Between Two Ecotypes Of Leymus Chinensis At Different Age Levels

Leymus chinensis is a perennial rhizome grass in the genus Leymus of Gramineae.It is a typical clonal plant with developed subterranean transverse rhizomes,which can rapidly clone and reproduce and integrate resources among plants through rhizomes.Leymus chinensis is widely distributed in the Eurasian steppe,and in China,it is mainly distributed in the grasslands of Northeast China,Inner Mongolia and Xinjiang.In the process of long-term adaptation to different environments,it gradually formed different ecotype,among which the most different type is grey-green type and yellow-green type.Leymus chinensis is an important species in grassland research and grassland restoration because of its resistance to cold,drought,salt and alkali and strong grazing tolerance.Among the intact Leymus chinensis clones,the first and second instar plants accounted for the largest proportion and contributed the most productivity,and as the vanguard of clonal expansion,the study on their physiological integration could provide a theoretical basis for more effective utilization of grassland resources and restoration of grassland.This experiment in grey green and yellow green two ecotypes age of first and second level plant as experimental object,uses different plant physiological integration,80% cutting processing make it happen one or two age levels were studied among the plant physiological integration direction and intensity,and compares the two ecological physiology integration strategy and ability difference,for more effective utilization of grassland resources and pasture and provide theoretical basis for choice of grass in recovery.The gray green and yellow green age of first and second level plant research shows that: in the absence of mowing and two under the condition of all age class tationally cutting processing,polish ecotype Yang two age class plant biomass index,stem,leaf traits indicators in the roots were not significant differences between connections and roots cut,shows two ecotype plants under Ck and all tationally cutting processing plant physiology integration did not occur.But in the age of a plant was mowing rhizome connecting two age plant aboveground biomass,plant height,leaf length,leaf width,leaf thickness,weight,leaf number and stem length and stem dry weight compared with roots to cut off the plant decreased significantly decline,a and connected to a current plant biomass,stem and leaf traits indicators compared with roots to cut off the plant is a significant rise.When the second-instar plants were cut,the first-instar plants connected with their rhizomes did not contribute significantly to the recovery of aboveground biomass,leaf and stem indexes of the second-instar plants after cutting.Although physiological integration function is beneficial to the old plant after mowing the ground part of the recovery,but under the age of a plant to cut processing plant roots connect a age of underground biomass,capillary root dry weight,root dry weight and root diameter than the roots to cut off the plant are significantly lower,the root system of the age of two root index compared with underground biomass and plant roots cut off two ages plants was significantly increased.This showed the under mowing process of physiological integration strategy choice,under the age of a plant to cut processing,both ecological l.chinensis physiological integration function actively support the age after mowing in aerial parts of the plant regeneration,and connected to the age of two plants by lowering their aboveground biomass,plant leaf and the stem traits to support an age,but two ages cutting processing plant,the plant roots is connected to the age is not to the age of two plants contribute to the recovery after mowing.When the related plant pairs are stressed,there is a division of labor among the plants,and the second-instar plants will forage to obtain distal resources and supply them to the plant pairs.Among the four mowing treatments,the physiological integration rate of the two ecotypes of Leymus chinensis reached the peak when the first-age plants were mowing,which indicated that mowing the first-age plants could significantly improve the productivity of the whole clone of Leymus chinensis,and it was a more effective method for grassland management and utilization.For yellow,green and gray green physiological integration research results show that the difference of two similar ecological plant physiology integration strategy,are all interference within the time limit of "discovery" and beyond limit interference "escape",but the integration ability difference,gray green type of interference tolerance type significantly stronger than the yellow and green.The results showed that 80% of all the plants were cut beyond the tolerance limit of yellow and green Leymus chinensis to cutting,and they had a physiological integration escape,which allocated a large amount of biomass to underground rhizome for storage,in order to escape from the disturbance of aboveground parts.Ash green type of interference tolerance than yellow,green,two root treatment age class type of ash green plants after receiving all plants to cut its aboveground biomass,leaf and stem type indicators were higher than the yellow green plants,underground biomass is below the yellow green plant,it shows that under 80% plant tationally cutting processing,gray green type plant stems and leaves still tend to regeneration.Under the cutting treatment of first-age plants,the physiological integration efficiency of grey-green plants was higher than that of yellow-green plants,which showed that the biomass of second-age plants of grey-green plants decreased less than that of yellow-green plants,while the corresponding indexes of grey-green plants associated with first-age plants of grey-green plants increased more than that of yellow-green plants.The results showed that the two plants had the same physiological integration strategy under the same disturbance,but the physiological integration ability was different,and the grey-green plant had higher integration efficiency than the yellow-green plant when the specific direction of physiological integration occurred.