Primary Mapping And Physiological Characterization Of Curled Leaf Mutant Cl1 In Brassica Rapa

Leaf is the main organ of photosynthesis,which maintains the growth and development of plants.The morphological and structural characteristics of the leaves also affect the adaptability of plants to the environment.For example,moderate curled leaves can reduce the transpiration and improve the drought resistance of the plants,improve the plant’s resistance.The morphological structure,area and color of the leaves directly determine the utilization of light energy,affecting growth and development of the plants,affecting quality and yield of the crops.In this study,the curled leaf mutant cl1,which was developed by EMS treatment,was used to identify its phenotype and physiological characterization,to observe the cell morphology,to analyze the genetic rules and to primary mapping of the curled leaf mutant cl1.The results of the present study are as follows.1.The mutant cl1 plants are short,the stem diameter,the leaf length and the leaf width are lower than those of the wild type plants.Compared with the wild type,the leaves of mutant cl1 are slightly darker than the wild type.The contents of chlorophyll a,chlorophyll b,total chlorophyll and carotenoids of mutant cl1 are higher than wild type.The photosynthetic rate of mutant cl1 are higher than that of wild type,while the transpiration rate,intercellular CO2 concentration and stomatal conductance are lower than wild type.It can be concluded that curled leaf is beneficial to photosynthesis.While the transpiration rate is low,improving the adaptability of plants to the environment.Through morphological observations such as scanning electron microscopy and paraffin section,it is founded that the curled leaf might be caused by the changes of cell morphology which led to the appearance of curled leaves.2.In order to reveal the genetic mechanism of the curled leaf mutant cl1,the nu mber of curled leaf plants and normal leaf plants in F2 segregation population are inv estigated.The results showed that the F2 segregation populations are consistent with 3:1 isolation and controlled by a dominant single gene.Through the verification and an alysis of BSR-Seq results,the chromosome region of the CL1 gene was determined.Using Chinese cabbage 3.0 data(http://brassicadb.org/brad/download Overview.php)and Primer5 to design SSR primers.The markers with polymorphism and closely linked to the mutant cl1 gene are screened.Finally,the cured leaf mutant CL1 gene is located in the 909.9 kb range of chromosome A02.