Anatomy of Root, Stem and Its Lignin Content and Expression of Related Key Genes in Lignin Synthesis of Lodging Resistant Brassica Napus L.
|School||Nanjing Agricultural College|
|Keywords||Brassica napus L. lodging resistance Anatomic structure lignin gene Differential expression|
Oilseed rape is one of the most important oil crops in the world. Lodging damage results in not only lower seed yield and oil quality, but also easier infection to the infection of Sclerotinia and more difficulties for mechanized harvest. So it is of a great significance to study lodging resistance in Brassica napus L.. And the study of lodging is just beginning in and out of China. It is important to explore a new method for improving the disease and lodging resistance of oilseed rape and other crops.Most lignin distributes in the plant lignification mechanical tissue and vascular tissue’s cell wall. It has increased the cell wall intensity and enhanced the ability of the cell wall watertightness and stem’s mechanical strength, as well as the liquid-transporting ability. Moreover, it also plays an important role in the cell’s resistant function.Objective of present paper are to study the internal structure difference between the lodging resistance and the lodging susceptable materials from the angle of anatomy by paraffin method, Measuring lignin content in different parts of different periods by Klason. Studying the differential expression of genes related to lodging trait between the lodging resistance and the lodging susceptible materials by the method of RT-PCR. The main results are as follow.1 Anatomical difference between Lodging Resistance and lodging Brassica napus L.Using paraffin method and safranine-fast green double stain to study the basal stems and main roots anatomy of Brassica oil(6 lodging resistant materials,5 easy lodging materials). Observed the stem structures of epidermis, cortex, collenchyma, vacular boundl and Pith. We have a preliminary study on basal stems and main roots structures and the proportion of the various parts of the relationship to lodging. The results show:(1) More collenchyma tissue was found in stem of lodging resistance materials than susceptible one at seeding. The vascular areas ratio out of the total stem base areas in lodging resistant materials was 13.1% higher than in susceptible materials. The number of vascular bundles between lodging resistant and susceptible materials had no difference. However the vascular bundles arranged more closely in lodging resistant materials compare with susceptible one.(2) More collenchymas and sclerenchymas found in the stem of lodging resistant materials than susceptible one at bolting period. The number of vascular bundles and vascular areas ratio of the total stem base areas had no difference between them. But the vascular bundles in lodging resistant materials arranged more closely than in the susceptible one.(3) The xylem areas ratio out of the total root base areas in root had no difference between lodging resistant materials than susceptible one at seeding period. Average number of vessels in the root of lodging resistant materials was 74.7 higher than of susceptible one. But the ratio of larger vessels in susceptible lodging materials was higher than in lodging resistant materials.(4) Xylem areas ratio out of the total stem base areas in the root of lodging resistant materials was 8.40% higher than of susceptible materials at bolting period. However the number of vesselsis in lodging resistant materials was higher than in susceptible materials.So, more collenchymas and sclerenchymas, more Vessels and vascular bundles arranged more closely in lodging resistant materials are the important anatomy traits at seeding period and bolting period.2 The determination of Lignin Content in Brassica napus L.Respectively measured different parts of lignin content in bloting and flowering periods, The results show:Except lignin content in roots is no significant difference, Other periods between the various parts of lignin content exist Significant difference or extremely significant difference. In root collar and stem of bolting period, lignin content is 0.95 percent and 1.90 percent higher in lodging resistance rape than in easy lodging rape;in root, root collar and stem of flowering period, lignin content is 2.53 percent,1.97 percent and 1.58 percent higher in lodging resistance rape than in easy lodging rape. Maybe more lignins are synthesised in stem and root collar at the bolting period and flowering period in lodging resistance rape.3 Related Gene Expression in the Lignin Synthesis of Brassica napus L.cDNA of the critical genes involved in lignin biosynthesis were amplified from bolting and flowering periods of different parts by RT-PCR. Using the primers designed from conservative regions of existing gene sequences. The results show:COMT gene expression has no difference of bloting and flowering periods in different parts. In root and stem of bloting, root of flowering, F5H gene expression in lodging resistance rape is higher than easy lodging rape;In root collar of bloting, stem, root collar of flowering period, F5H gene expression between lodging resistance rape and easy lodging rape almost have no difference.4CL gene expression in root, root collar of bloting and flowering periods have significant difference, lodging resistance rape is significantly higher than easy lodging rape; But in stem of bloting and flowering periods, lodging resistance rape and easy lodging rape expression has no significant difference. It is indicated that F5H and 4CL gene may be the key genes of associated with the rape plant lodging resistance.