To investigate the effects of low phosphorus stress on five endogenous hormones(abscisic acid,gibberellin,growth hormone,zeatin and solanum lactone)in the roots and leaves of Pueraria lobata,and to pro-vide a reference for the selection and breeding of low phosphorus tolerant Pueraria species.Kudzu from different provenances(Australian Kudzu,Hunan Kudzu from China and Jiangsu Kudzu from China)were selected as ex-perimental materials,and the hydroponic experiments with three phosphorus nutrient levels were conducted(nor-mal phosphorus 0.5 mmol·L-1,low phosphorus 0.05 mmol·L-1 and extremely low phosphorus 0.005 mmol·L-1 KH2 PO4 concentrations were set).The contents of endogenous hormones in roots and leaves of Kudzu seed-lings were determined by enzyme-linked immunoassay.The results showed that the abscisic acid content of kudge root decreased with the decrease of P concentration,and the abscisic acid content of Kudzu leaf decreased first and then increased with the decrease of P concentration.The contents of gibberellin,zeatin,growth hormone and monocrotaline in kudzu root increased with the decrease of P concentration.The contents of gibberellin and growth hormone in Kudzu leaf also increased with the decrease of P concentration,and the contents of zeatin and dictamnolide first increased and then decreased with the decrease of P concentration.
In order to evaluate the carbon storage of grassland ecosystem in Inner Mongolia,the paper puts forward suggestions on ways to realize the carbon sink potential of grassland.Based on the formation mechanism of grassland carbon pool,the carbon sequestration potential of grassland was evaluated from two aspects:grass-land biomass and grassland soil carbon sequestration.The grassland biomass carbon sequestration potential was calculated using the net ecosystem productivity method,and the grassland soil carbon sequestration potential was calculated using the grassland soil organic carbon content.The results are as follows:The total carbon sequestra-tion in Inner Mongolia grassland in 2020 will be 47.4×108 t,the carbon sequestration in grassland soil accounted for 96.43%of the total carbon sequestration in grassland,and the biological carbon sequestration in grassland accounted for 3.57%of the total carbon sequestration in grassland.The carbon sequestration potential in grass-land soil plays a leading role.The amount of carbon sequestered in grasslands of Inner Mongolia was unevenly distributed,and the amount of carbon sequestered in grasslands of the eastern League(city)was higher than that of the western League(city).The amount of carbon sequestered in grasslands of Xilin Gol League and Hulunbuir was higher,which were 13.95×108 t and 13.89×108 t,accounting for 29.44%and 29.31%of the whole re-gion,respectively.Inner Mongolia grassland is a huge carbon pool,and it is of great significance to focus on the realization of the value of grassland carbon sink ecological products.Find out the amount of grassland carbon sink,increase grassland carbon sink resources,and accelerate the research and development of grassland carbon sink.
To establish a grazing and livestock balance model and an optimized production model,the graz-ing and livestock balance,grassland biomass,methane emissions and economic income and expenditure of family pasture in the desert grassland area of Urad Middle Banner in Inner Mongolia under different stocking rates were analyzed,in order to provide scientific basis and decision support for the production and operation of family pas-ture in this area.Field investigation and simulation analysis were adopted,the relevant data and parameters were collected,and the grass and livestock balance model and optimized production model were established,verified and analyzed.The results showed that the grazing and livestock balance and economic benefits of family pasture in this region were closely related to stocking rate.With the increase of stocking rate in pasture,there was a state of short supply between the actual energy intake of livestock and the energy required for maintenance,and only the grassland energy remained at the stocking rate of 0.1 sheep unit/hm2 and 0.33 sheep unit/hm2.Further-more,methane emissions increased with the increase of stocking rate in pasture,while the biomass of grassland gradually decreased.Appropriate stocking rate can improve economic returns,combining ecological and econom-ic benefits and local conditions,it is recommended to maintain pasture stocking rate between 0.33 sheep units/hm2～0.55 sheep units/hm2.Reasonable adjustment of the stocking rate in pasture is of great significance to promote the sustainable development of grassland ecological environment and the healthy development of animal husbandry.
Grazing is one of the main utilization methods of grassland ecosystem,plant functional traits re-flect the response of vegetation to environmental changes.In order to explore the effects of different grazing inten-sity on plant functional traits,two dominant species Cleistogenes songorica and Artemisia frigida were selected based on the long-term grazing experimental platform of desert steppe research in Inner Mongolia,and 7 main functional traits of these plants were analyzed.The results showed that the natural height of reproductive bran-ches,natural height of vegetative branches,crown width,basal stem and number of reproductive branches of Ar-temisia frigida decreased significantly with the increase of grazing intensity.Light grazing increased the number of basal stems and reproductive branches of Cleistogenes songorica,but moderate and heavy grazing had negative effects on other functional traits of Cleistogenes songorica.The functional traits of Cleistogenes songorica differed significantly in July and August,while there was no significant difference in that of Artemisia frigida.Therefore,different dominant plants in desert steppe responded differently to grazing intensities and time,which was of great significance for studying the response strategies of plants in desert steppe to long-term grazing disturbance.
草原蝗虫的分布和发生与气温、地形、地貌、海拔、土壤类型、草地类型、牧草种类、植被高度、植被盖度、天敌等因素密切相关.由于内蒙古东西跨度大,气候条件悬殊,形成了不同的草原类型,因而分布在内蒙古草原上的蝗虫种类也不尽相同.
