Study On The Cost Of Leaf Construction And Influencing Factors Of Desert Plants In The Northern Foot Of Qilian Mountains

Leaf construction cost（LCC）is a measure of the cost of energy input per unit mass or area of leaf,and its variation reflects the energy use strategy and environmental adaptation of plants.In-depth studies on the variation of leaf construction cost and the interrelationship between construction cost and biotic and abiotic factors are of great significance to the study of the energy ecology of desert plants.Most previous studies have focused on grassland and forest ecosystems,comparing establishment costs between invasive and native plants,but there are still few studies on establishment costs in desert ecosystems in China.Desert areas account for20%of the land surface,and plants growing in desert environments show different adaptation strategies from other ecosystem plants in response to environmental stresses such as drought,high temperature and salinization.Taking the establishment cost of desert plants as the research object and combining biotic and abiotic factors on the mechanism of leaf establishment cost,it will not only help to fill the gap of this research in desert ecosystems in China,but also The study will not only help to fill the gap of this research in China’s desert ecosystems,but also provide some scientific suggestions for the conservation and vegetation selection of desert ecosystems.In this study,the main desert plants in the desert area of the Hexi Corridor were used as research objects.The differences in LCC between different ecosystems and different plant functional groups were compared,and the relationship between LCC and other leaf traits and the variation pattern of LCC with environmental factors were analysed,with the aim of exploring the variation relationship between the establishment cost of desert plants and other factors:1)Cost characteristics of main desert plant leaves in the desert area at the northern foot of Qilian Mountains:The average leaf establishment cost of desert ecosystems in the study area was 1.25±0.22 g·g^-1,the lowest among known studies,and highly significantly different from other ecosystems.The plant with the lowest leaf establishment cost was Iljinia regelii(0.69 g·g^-1),which was the lowest value of leaf establishment cost for terrestrial plants.Different genetic characteristics determine the upper limit of plant leaf plasticity.Desert plants of different species,families,genera,and functional groups will fully utilize their unique and diverse advantages to maximize resource utilization in desert environments,and change their leaf properties through different adaptation strategies to adapt to environmental stress and achieve similar evolutionary trends.2)Differences in internal factors affecting the construction cost of desert plants in different functional groups:Herbs and shrubs respond to changes in construction costs with similar changes in leaf properties;The response of unit mass LCC in C3 plants to leaf traits is more susceptible to N compared to C4 plants;Succulent and non succulent plants have chosen different leaf trait adaptation strategies to achieve the optimal balance of data utilization;The overly conservative adaptation strategy of nitrogen fixing plants gives them an advantage over non nitrogen fixing plants in desert environments due to their high plasticity in leaf traits.Reducing the cost of leaf construction per unit mass rather than per unit area is more beneficial for plants to adapt to arid and high salt desert habitats.3)Response mechanism of leaf construction cost of different functional groups of plants to different environmental factors in the desert area at the northern foot of Qilian Mountains:Desert plants are always subjected to environmental stresses such as drought,high temperature,and high salinity during their evolution;A single factor has a more significant impact on the cost of herbaceous construction,while shrubs are limited by multiple environmental factors,and their adaptability may not be as extensive as herbaceous plants;Due to the harsh and diverse environmental conditions,C3 and C4 plants exhibit approximately consistent coping strategies or mutation mechanisms in their evolutionary process to cope with such ecological environments;The environmental impact factors on succulent and non succulent plants are different.The unit mass LCC of succulent plants decreases with the decrease of annual average temperature,while the unit mass LCC of non succulent plants decreases with the decrease of annual precipitation and average temperature;The environmental impact factors on nitrogen fixing and non nitrogen fixing plants are different.The unit mass LCC of nitrogen fixing plants decreases with the increase of soil carbon content,while the unit mass LCC of non nitrogen fixing plants decreases with the increase of soil conductivity.In summary,although desert plants exhibit different survival strategies due to genetic factors,the overall leaf construction cost tends to be on the low side due to the constraints of the harsh desert environment.Plants use their significant advantages to modify the relationship between leaf traits and leaf construction cost in response to environmental stresses such as drought and high salinity.Analysis of leaf construction cost in relation to environmental factors further indicates that soil EC and annual precipitation are the key factors affecting establishment costs in desert plants.Furthermore,the way in which different functional groups of plants exhibit similar trends to reduce establishment costs under the same environmental influences demonstrates that the desert environment has created a special species of desert plants under the influence of the desert environment.Low cost plants are more willing to cope with stress conditions by adapting to environmental changes,while high cost plants resist stress caused by environmental changes by changing their own traits.