| Litsea coreana Levl.var.sinensis is an evergreen small tree of Lauraceae.It is a raw material plant for Chinese characteristic tea and has high economic value.For a long time,scholars have tended to pay attention to the substances contained in L.coreana var.sinensis and their effects on the pharmaceutical field,but there is a lack of understanding of the plasticity of leaf traits and the effects of environmental factors on leaf plasticity.Studying the relationship between leaf traits and environmental factors will help to better explain the response and adaptation strategies of plants to the environment,and is of great significance for clarifying the adaptability of plants to future climate change.Therefore,the natural populations of L.coreana var.sinensis in 5 counties of Guizhou Province were selected as the research objects,and the phenotypic traits,anatomical structure traits,chemical traits,geographical,climatic and soil factors of various populations of leaves were determined.To explore the leaf traits and adaptability variation of L.coreana var.sinensis in Guizhou Province,and to clarify the correlation between leaf traits in response to geographical changes and leaf traits,as well as the nutrient restriction in existing plants.The relevant conclusions can provide a theoretical basis for the conservation management and sustainable management of L.coreana var.sinensis.The main conclusions are as follows:(1)The phenotypic traits of the leaves of L.coreana var.sinensis play an important role in the continuous adaptation of plants to environmental changes,and there are significant differences among and within populations(P<0.01),and among populations variation is the main source of phenotypic variation.The mean coefficient of variation of leaf phenotypic traits was 13.5 %,and the relative chlorophyll content and leaf dry matter quality in the population were stable compared with other individual traits.The ZA(Zhengan county)population(CV= 15.68 %)had the richest leaf phenotypic diversity.In addition,the variation of leaf phenotypic traits was significantly correlated with geographic,climatic and soil factors,showing a continuous pattern of changes with longitude,latitude and altitude.Within a certain range,as the altitude increases and the latitude and longitude decrease,the leaves become larger and wider;Increase temperature and precipitation will gradually widen the blades.With the improvement of soil fertility,the leaves will become larger and wider and conducive to dry matter accumulation;The two traits of leaf dry matter mass and chlorophyll relative content are affected by environmental factors and have less variation than other phenotypic traits.(2)The leaf structure of L.coreana var.sinensis is heterofacial leaves,with well-developed sponge tissue and shade tolerance characteristics.There were significant differences in anatomical structure traits among and within populations(P< 0.01),and the variation among populations was the main source of anatomical structure variation in L.coreana var.sinensis.The mean coefficient of variation was 10.43 %,and the leaf phenotypic diversity was the most abundant among DZ(Daozhen county)population(CV= 12.52 %).The anatomical structure of the leaves of L.coreana var.sinensis was significantly correlated with geographic,climatic and soil factors.With the increase of altitude,mean diurnal range(Bio2),isothermality(Bio3),Precipitation seasonality(Bio15)and decrease in latitude and longitude,the anatomical structure of L.coreana var.sinensis leaves became thicker.Moreover,leaf anatomical structure traits were positively correlated with most soil nutrients,and soil salinization and high mineral content led to thinning of leaf tissue structure.(3)The genetic diversity of C,N and P stoichiometric characteristics of L.coreana var.sinensis leaves was high,and the differences among populations and within populations reached a very significant level(P< 0.01).It has a low LN and LP content,but a higher LC/LN,which is characterized by a ‘slow growth strategy’ plant.The coefficient of variation of each population was more than 30 %,and the variation of LC,LN and LP stoichiometry characteristics was abundant,among which the diversity of stoichiometric characteristics of ZA population(CV= 56.53 %)was the most abundant.The stoichiometric characteristics of LC,LN and LP in L.coreana var.sinensis leaves were significantly correlated with geographic,climatic and soil factors,showing a pattern of latitude and longitude,but not with altitude.Among the climatic factors,LC is mainly affected by the annual mean temperature(Bio1),LN is mainly affected by the temperature annual range(Bio7),and LP is mainly affected by the precipitation of wettest quarter(Bio16).With the increase of soil nutrients,LC decreased and the LN and LP content of leaves increased.LC content was negatively correlated with most soil nutrients,and only positively correlated with soil C content and mineral elements.But the LN and LP contents and soil nutrients were mostly positively correlated.(4)The mineral element characteristics of the leaves of L.coreana var.sinensis were different in different environments,and the mineral element of the leaves reached a very significant level among populations and within populations(P<0.01).The largest variation in the coefficient of variation was LFe(43.74 %).The mean coefficient of variation of mineral content in leaves of various populations was 28.80 %,and the XS population diversity(CV=35.34 %)was the most abundant.There was a significant correlation between the mineral content of the leaves of L.coreana var.sinensis and geographic,climatic and soil factors,showing a distribution pattern with longitude,latitude and altitude.Among the climatic factors,LCa showed an increasing trend with the increase of Bio1 and precipitation factors.LK is mainly affected by Bio15,temperature and Precipitation of coldest quarter(Bio19).Bio3 mainly affects LMg content;The LFe content was mainly affected by Bio1,Bio2,Bio3 and the precipitation of wettest month(Bio13).With the increase of soil fertility,LCa content increased,while LFe content showed a decreasing trend.Moreover,the content of LK and LMg is less affected by environmental factors than that of LCa and LMg.(5)In the face of environmental changes,the phenotypic traits of L.coreana var.sinensis leaves are manifested as synergies and trade-off between traits to adapt to environmental changes.The anatomical structural traits of the leaves are manifested as synergistic variation between traits in response to environmental changes,and there is a trade-off between the stoichiometry ratio of the leaf and its elements.Based on the above results,the following recommendations are made: firstly,considering the variation characteristics of leaf traits among populations,the collection of germplasm resources in the future should consider collecting from different populations.Secondly,for populations with abundant variations,such as ZA populations,priority protection or in situ conservation is required.For population with low variation level and weak survivability,such as KY(Kaiyang County)population,a combination of in-situ conservation and off-site transplantation should be considered,and population size should be increased through multi-route expansion.Finally,the selection and breeding of L.coreana var.sinensis varieties should be strengthened,individuals or populations with excellent comprehensive traits should be selected,and artificial breeding to expand the quantity of excellent germplasm resources,so as to realize the scientific protection and sustainable development of the existing resources of L.coreana var.sinensis. |
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