Creation And Physiological And Biochemical Characteristics Study On Autotetraploid 'Chuanxinhong' Radish

Autotetraploid had been obtained by inducing with colchicine solution from the diploid radish(Raphanus Sativus L.). The diploid and autotetraploid plants were studied on the characteristics of morphology, cytology, agronomy, nutrition quality, photosynthetic properties and other physiological and biochemical characteristics.1 The diploid radish (Raphanus sativus L.) was induced by treating the apical portion of cotyledon with different concentrations of colchicine solution. The autotetraploid plants were obtained by identifying the characteristics of morphology, cytology, agronomy, and nutrition quality. The results showed that the best effect of autotetraploid was obtained with 0.2% colchicine solution for 6 times, and the frequency was 4.5%. Compared with the diploid plants, the autotetraploid plants showed the 'enormous characteristic' in the thickness of leaves, the size of stomatas, the number of chloroplasts in a leaf guard cell, the size of flower organs, the length and the width of pollen grains, the size of seeds and so on. The height of plants, the thickness of ten leaves and the weight of taproot of autotetraploid were significantly higher than diploid. The nutrition quality of autotetraploid radish was also much better than diploid radish, such as vitamin C, soluble protein, organic acid, soluble sugar and reductive sugar.2 This research had studied the cytomorphology of anther development in diploid and tetraploid radish by examining the section of organic tissues in paraffin wax. The observations showed that the anther of diploid and tetraploid radish turned into 4 chambers and divided into two half, and the cross section resembled the shape of butterfly. But the chambers of tetraploid radish were mostly abnormal and the development of microspore in the same anther of diploid and tetraploid were not in same stage.3 The diploid radish (Raphanus sativus L.) and autotetraploid radish that was induced by colchicines were measured by using the Li-6400 portable photosynthesis system in sunny days. The results showed that during the initial course of light induction treatment, Net photosynthe (Pn) and stomatal conductance (Gs), CO₂ concentrations (Ci),Transpiration rate in autotetraploid was higher than diploid radish.The results also showed that the net photosynthetic rate (Pn), stomatal conductance (Gs), transp iration rate (Tr) and the content of chlorophyll a (chl.a) and chlorophyll b (chl.b) changed similarly. They all dropped continually at the stress prophase, or increased first and later decreased, they dropped again rapidly at anaphase. Transpiration rate (Tr) were increased first and later decreased, the content of chlorophyll a (chl.a) and chlorophyll b (chl.b), chl were reduced along with the chromosome doubling increase and were also rose first and later decreased.All the changes were same approximately in diploid and autotetraploid radish, the content of Car/chl content change scope was smaller and the content of chl.a/chl.b was first rised and then droped and rised again in the end.4 Changes of activities of superoxide dismutase (SOD),and peroxidase (POD), catalase (CAT),and contents of malondialdehyde (MDA),free amino acid (O₂^?),soluble protein, H₂O₂, ion leakage in diploid and autotetraploid radish on drought stress were investigated. The results showed that the changes were same approximately in diploid and autotetraploid radish. The effect of drought stress on SOD, POD, CAT was V-tye.W-tpe and N-type. Activity of MDA, the content of soluble protein and the activity of O₂^? and H₂O₂ were increased first and later decreased. And the ion leakage increased continually. The tetraploid radish comparatively diploid had the adaption adverse circumstance the ability.