Study On Photosynthetic Physiology And Leaf Anatomical Structure Of Different Rubber Tree Lines

The Brazilian rubber tree is a tall tree that is native to the Amazon family in the Amazon basin of South America.The rubber obtained by tapping rubber is one of the most important industrial resources.Rubber trees are sensitive to environmental factors such as light,temperature,gas and water.Long-term artificial selection breeding also makes the genetic basis of rubber tree cultivars increasingly narrow.Rubber tree cultivars and wild germplasms have great differences in response to environmental factors and photosynthetic characteristics,which also provide a material basis for high-light-efficiency breeding.At present,there are few systematic studies on the differences in photosynthetic characteristics and light effects between rubber trees in the academic community.This study explored the differences in photosynthetic physiology,environmental factor response,and light-adaptive anatomical structure of different types of cultivars,aiming to find light between different genotypes.The effect difference,typical characteristics and different traits are related to each other.It is intended to provide theoretical basis for the research and development of rubber tree high-efficiency breeding,variety recommendation,cultivation technology and so on.This subject is based on 10 different types of rubber tree species and wild germplasm with large differences in growth and yield traits in the test site of Zhangzhou Academy of Thermal Sciences.The Li-6400 photosynthetic apparatus is used to apply paraffin sections and transmission electron microscopes.Ultrastructural and other related technologies,in the controlled natural environment,observed physiological parameters such as photosynthetic parameters,photosynthetic pigments,photosynthetic enzyme activities,etc.,studied the microscopic anatomy and ultrastructural characteristics of the leaves,and selected the most suitable The photosynthesis fitting model was used to analyze the intrinsic correlation between parameters by using principal components and clustering methods.Results are as follows:1.Light response curve and CO2 response curve model fittingThe Photoresponse Characteristics and CO2 Characteristics parameters of 10 rubber trees by four models.The results show that the optimal parameters of Pnmax,LSP and Rd in the optical response are Index model,and the Non-orthogonal hyperbolic model of LCP.The Right angle hyperbolic correction model is a fitting model for C02 response and is similar to the measured values.Under natural light,the high photosynthetic efficiency varieties,such as Reken 525 and Reken 628;PR107 and XJ000517 has a lower LCP and higher LSP,showing better light adaptability.The difference between CCP and CSP of wild germplasm XJ000517 and XJ005970 is large,indicating that it has a wide range of CO2 concentration.2.Comparative analysis of photosynthetic physiological parameters of different linesIt was shown that the chlorophyll a/b values of XJ000068 and Reken 628 were relatively high,while the RuBp and Rubisco activities of PR107 and Reyan 879 were relatively high.Photosynthetic measurements of 10 lines showed that XJ005970,Reken628 and XJ000517 had lower Tr and higher WUE,shows that it can quickly close the pores under strong light to reduce the transpiration rate.The Pn parameter values of Reken 628 and Reken 525 are relatively high,and strong photosynthetic efficiency.3.Comparative analysis of leaf anatomical structure and chloroplast ultrastructureThe observation of the blade anatomical structure of 10 rubber trees shows that the blade thicknesses such as XJ000044 and XJ005970.XJ000044 and XJ005970 have strong adaptability to the external environment.The air holes such as XJ00044 and XJ000068 are small and dense,and can respond to external environmental factors more quickly..Further,the ultrastructure of chloroplast showed that the area of starch granules in XJ000517 and Reken 628 was relatively large,while the chloroplasts such as Reken 525 and Reyan 879 were relatively large.Principal component analysis by anatomical parameters,It indicates that the starch grain area,chloroplast area,stomatal area and grid-to-sea ratio of the palisade tissue are the main factors for adapting the leaves to the external environment.Using the main factor,the test items are grouped into three categories,the genotype with strong adaptability to the external environment is XJ000044;the adaptability to the external environment is strong,and the photosynthetic efficiency is high,such as Reken 525 and Reken 628.Variety;XJ005970,RRIM600 and PR107 are generally suitable for the external environment.Wherefore,by combining the genetic background of the tested varieties,high-yield heat research 879 variety,It has a large number of chloroplasts,higher values of LCP and LSP,and stronger photosynthetic capacity.However,the activity of RuBp enzyme and the activity of Rubisco enzyme are higher.The variety will restrict its photosynthetic efficiency.Reken 525 and Reken 628 are both excellent varieties of bakelite,Its parameter value of Chl(a/b)is relatively large,the number of chloroplasts is large,with strong photosynthetic efficiency,and strong adaptability to illumination.relatively high of XJ000044 and XJ000517 varieties,It has a the number of starch granules,the thickness of the leaves,the ratio of the palisade tissue to the thickness of the sponge tissue.XJ000044 and XJ000517 varieties have strong adaptability to the external environment,In the breeding process,the variety of parents is unknown,the growth status and the ability to produce rubber are low,and the variety can be crossed with other varieties with good traits to breed new varieties,which is beneficial to the promotion of varieties.