The Study On Genetic Regularity And Physiological Characteristics Of The "Ginkgo Leaf" Mutation Of Cucumber

The cucumber mutations were scarce germplasm resources, but the most mutations had poor growth. To protect these germplasm resources we should explore the reasons of the poor growth of the mutations. Corresponding measures should be taken to change the deficiency. The inheritance and the photosynthetic characteristic of the leaf, the micro structure of leaf and ultrastructure of chloroplast, the relationship between cucumber and hormones, the content of carbohydrates and the activity of related enzymes were studied in this experiment in order to find out the poor growth reasons. The main results of the study were listed as the following:1. The leaf of "ginkgo leaf" mutation of cucumber was similar as ginkgo leaf, the leaf was divided and the leaf vein was different from the normal. The petals of the male and the female flowers were divided. The plant height, the internode length and the leaf area were very significant less than those of the normal cucumber. This showed that the mutation had poor growth.2. The mutation and the normal cucumber were crossed and then produced the next generation. F1had normal phenotype. The segregation ratio was3:1in the self-crossed progeny of F1. The results of the test cross of the mutation and F1was1:1. These showed that the "ginko leaf" belonged to nuclear inheritance and it was controlled by a recessive gene.3. The photosynthetic rate of the mutation was lower than that of the normal, but it had no significant difference at maturity stage, the photosynthetic pigment content had no significant difference between the normal and the mutation at maturity stage. And the photosynthetic pigment content was significantly less than the normal at the other stage. The ratio of ETo/RC of the mutation was significant less than the normal. It showed that the energy which to be used to move electron transport was less than the normal. The respiratory rate of the mutation was significant higher than the normal one, The results showed that the higher respiration consumption was not conductive to the growth of the plant.4. The thickness of the leaf, palisade tissue, spongy tissue, upper epidermis and lower epidermis in the mutation cucumber were significantly more than those in the normal cucumber, the sponge tissue looseness of the mutation was higher than the normal one. The number of chloroplast of the mesophyll in the mutation was significantly more than that in the normal cucumber. There was no significant difference between the mutation and the normal type in the number of grana, but the grana lamella number of mutation was very significant less than that of the normal cucumber. The number and size of starch grain in the mutation were significantly higher than those in the normal type.5. The plant height and the internode length of the mutation couldn’t recovered to the normal levels after spraying the exogenous GA3and IAA. But the content of GA3of mutation was significant higher than the normal, the content of IAA had no difference between the mutation and the normal. These results showed that the"ginko leaf" mutation of cucumber may be a GA and IAA insensitive mutation. The content of ZT of the mutation was lower than the normal cucumber and the difference was very significant. There was no significant difference between the mutation and the normal type on the content of ABA at seedling sage. The content of ABA of the mutation was very significantly lower than the normal cucumber at the maturity stage. The content of IBA of the mutation was very significantly lower than the normal cucumber.6. The content of soluble sugar of the mutation was very significantly more than the normal cucumber and the content of sucrose and starch was significantly more than the normal one. The activity of sucrose phosphate synthase of the mutation was significant more than the normal cucumber, but the activity of sucrose synthase between the mutation and the normal cucumber has no significant difference, so it was beneficial to the synthesis of sucrose. The activity of amylase of the mutation was significant less than the normal one, so it went against the hydrolysis of the starch.7. The root activity of the mutation was significant lower than the normal cucumber, we can know that the lower roots activity was not conductive to absorb the water and minerals, so it could lead to the poor growth.