1、寧夏大學碩士學位論文增強UV-B輻射對3種藥用甘草幼苗生長、形態(tài)結構及生理特性的影響姓名：于海寧申請學位級別：碩士專業(yè)：植物學指導教師：彭勵2011-03II Abstract As the depletion of stratospheric ozone layer, sub-aerial ultraviolet (UV-B) radiation arriving the earth surface becomes stronger,

2、 whose effect on biology and ecology effect has been concerned. Effect of enhanced UV-B radiation on growth, morphology and physiological characteristics of three species of radix glycyrrhiza (Glycyrrhiza uralensis Fisch

3、., G. inflata Bat., G. glabra L.)seedlings which distributed in arid-semiarid region had been systematic studied. The results showed: 1. Enhanced UV-B radiation treatment on three species of radix glycyrrhiza seedlings g

4、rowth are inhibited, performance in seedlings plant height, biomass, root-shoot ratio all changes with UV-B radiation time and doses. Two processing groups of three species of radix glycyrrhiza seedlings compared with th

5、e control height reduce for 3.5-4.3%, biomass for 32.3-42.0%, root-shoot ratio for 4.0-5.2%, respectively. Meanwhile, UV-B radiation inhibited leaf growth, showed reduced leaf area, compared to the control the two treatm

6、ent groups were reduced by 14.0% and 22.1%, respectively. Research shows that three radix glycyrrhiza seedlings acclimate to enhance of UV-B radiation treatment were different. The strongest is Glycyrrhiza uralensis Fisc

7、h., G. glabra L. is the weakest. 2. Enhanced different levels of UV-B radiation on the anatomical structure of leaves of these seedlings have a severe impact. Low doses, short time UV-B radiation cause thre

8、e seedlings appear black spots, leaves after prolonged and dose with radiation increases, blade all appear to become yellow, curly falls off phenomenon, which eventually led to the ground plant death. Further studied fou

9、nd that enhanced UV-B radiation caused blade organizational structure was damaged. As the radiation time and radiation dose increases, the leaf epidermal cells are subject vary degrees, reduce the radial epidermal cells,

10、 and in severe epidermal cell structure completely destroyed, some epidermal cells stained dark matter (tannins and other phenols) increased. Observed on the leaf tissue, with UV-B radiation intensity increases palisade

11、tissue structure is damaged of mesophyll, the cell deformation, arrangement becomes disordered. Chloroplast which within the palisade tissue was damaged, chloroplast envelope fuzzy, the number of osmiophilic particles wa

12、s significantly increased. 3. Enhanced UV-B radiation treatment the photosynthetic indexes of three species of radix glycyrrhiza seedlings decline. Accordingly, the photosynthetic pigment content decreased. 4. Three spe

13、cies of radix glycyrrhiza seedlings to UV-B radiation has a certain degree of self-defense capability, and its defense mechanisms mainly through the cumulative effect of protective enzymes of SOD, POD, CAT and accumulati

14、on the UV absorption material to reflect. The performance of a certain dose short time treatment, three protective enzyme activities increased, with the treatment time and then activity decreased. Compared with the contr

15、ol, UV-absorbing substances in the leaves at different levels of UV-B radiation after 7 days, three species of radix glycyrrhiza seedlings are in total radiation reached the maximum, 2.09 times, 1.54 times and 1.15 times

16、 respectively, and the former two with the treatment dose and prolonged were increased. There is such a defensive capability adapt to species differences in UV-B radiation. Performance the strongest is Glycyrrhiza uralen