| The study of biodiversity and plant environmental adaptability has been a hot topic and trend in ecological research in recent years.By studying both,the response of plants to the environment can be understood from different dimensions.It is of great significance for humans to protect plant biodiversity and understand the response of ecosystems in alpine regions to climate change.The alpine meadow ecosystem is a part of the alpine mountain ecosystem.As a typical representative of plateau areas,alpine meadows are sensitive to climate change and are an important part of vegetation research in alpine ecosystems.As an important vegetation belt in the Sejila Mountain area,alpine meadows are not only an important component of the Sejila Mountain vegetation,but also a natural pasture for local residents to graze in summer.Therefore,the spatial shift and decline of the region can fully reflect climate change information.The accumulation of regional sample data helps to explore the plant biodiversity of alpine meadows and to some extent,clarify their environmental adaptability.In view of this,this article chooses to analyze and study the environmental adaptability of plant biodiversity and leaf anatomy and phenotypic traits of two dominant plants in alpine meadows from the tree line of Sejila Mountain to the gravel beach(between 4400 m and 4600 m)using sample survey methods and indoor experimental methods.The following conclusions are drawn:(1)The species composition of the alpine meadow sample plot in the 4400 to 4600 meter area of Sejila Mountain is relatively small,and the species categories that make up the community are simple.There are a total of 8families,14 genera and 15 species of dominant plant species in the study area.The main dominant species are in the species composition,with Rosaceae,Cyperaceae,Compositae,and Polygonaceae plants as the main dominant species,while Compositae plants are the most dominant.The dominant populations in the study area are Polygonum multiflorum,Kobresia breviflora,Liontooth shaped Chrysanthemum,and Hard leaved Chrysanthemum.Other accompanying species include Pleurophyta coriander leaf Potentilla,West Sichuan tongueless Chrysanthemum,and Three Veined Plum Blossom Grass.In the range from 4400 m to 4600 m above sea level,the composition of plant community at different altitudes is significantly different.The average Shannon Wiener index is 0.135,the average Margalef richness index is 2.448,the average Simpson index is 0.438,and the average Pielou evenness index is 2.416.After analyzing the diversity index,it was found that the overall variation pattern of the species richness index increased first and then decreased with the increase of altitude,showing a single peak curve change.Based on current research on alpine meadows in the Qinghai Tibet Plateau,it has been found that the biodiversity of alpine meadows in the plateau region first increases and then decreases with increasing altitude.The overall variation pattern of species richness index is that it first increases and then decreases with increasing altitude,showing a unimodal curve.The highest value appears between 4450 m and 4500 m,and the lowest value appears at 4600 m;The overall variation of Shannon Wiener diversity index is the same as that of species richness index,but the lowest value appears at 4400 m and the highest value appears between 4500 m and 4550 m;The overall variation pattern of the Simpson diversity index is the same as that of the species richness index,with the highest value appearing at4450 meters and the lowest value appearing at 4600 meters;The Pielou evenness index shows a linear variation,gradually decreasing with increasing altitude.The maximum and minimum values appear at 4400 m and 4600 m respectively,indicating that the biodiversity of alpine meadows in the region changes with altitude.(2)The thickness of leaves,upper stratum corneum,upper and lower epidermis,and barrier coefficient of two dominant species of plants,Liontooth shaped Chrysanthemum and Hard leaved Chrysanthemum,increase with altitude in the 4400 m-4600 m alpine meadow of Sejila Mountain.After analysis,it was found that environmental conditions have a crucial impact on plant changes.The internal structural characteristics of plants can also reflect the co evolution between plants and the environment,and plants will make corresponding adaptations according to changes in the environment.The study found that the plant adaptability of the alpine meadow from the tree line of Sejila Mountain to the gravel beach has an important relationship with the environment.The Pearson correlation analysis of the thickness of various anatomical indicators(leaves,upper and lower epidermis,upper cuticle,Palisade cell,spongy tissue,palisade coefficient)of the leaves of two species of plants,Aegilops tauschii and Aegilops rigida,showed that the anatomical characteristics of the leaves changed consistently with altitude,There is also a significant correlation between anatomical indicators,and the co evolution of anatomical features is also an important adaptation strategy for plants to environmental changes.This indicates that the dominant plants in the alpine meadows in this region have significant environmental adaptability with changes in altitude,and there is a significant co evolution with changes in altitude.(3)In the alpine meadow plants ranging from 4400 m to 4600 m in the Sejila Mountain,the research results of Liontooth like Chrysanthemum and Hard leaved Chrysanthemum showed high phenotypic morphological diversity in leaf and stem characteristics,with diversity indices ranging from 0 to 2.002 and 0 to 1.992 respectively,and coefficient of variation ranging from 0% to56.22% and 0% to 46.66%.This indicates that the phenotypic traits of this germplasm resource have high richness and wide genetic diversity.The larger the coefficient of variation of traits,the greater the difference in phenotypic traits.There is a significant coefficient of variation between the lion toothed and hard leaved wind hairy chrysanthemums,indicating that the two plants have different adaptation strategies at different altitudes,and the diversity index of quality traits is lower than that of quantitative traits.At 5 altitude gradients ranging from 4400 m to 4600 m,there is different significance in 8 phenotypic traits between the lion toothed and hard leaved Chrysanthemum.The impact of altitude gradient on phenotypic traits shows different changing trends.The phenotypic traits of plant height,leaf length,and petiole length of two plants exhibit consistent changes with altitude gradients.The macroscopic changes in leaf thickness are also consistent with the microscopic changes in leaf anatomy.And the two plants showed consistent adaptive performance in some traits as the altitude gradient increased,while in the leaf angle trait,the changes in the two plants showed significant inconsistency,indicating that plants exhibited diverse adaptive strategies while changing with the altitude gradient.After Pearson correlation analysis,it was found that there were different significant correlations between the phenotypic traits of the two plants.Among them,plant height,leaf length,and petiole length showed significant and extremely significant correlations,indicating that as the altitude gradient increased,the plant height tended to become shorter,and the leaf length became shorter,resulting in smaller leaves.This reflects the adaptation strategy of plants to habitats,and there is a clear result of co evolution,To achieve a balanced utilization of resources between plant leaves and their plants. |
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