| For comprehensive understanding the effects of global environmental changes, especially of increasing UV-B radiation, on the growth and development about every stage of Chondrus ocellatus Holm in whole history life, many Physiology and Biochemistry Values (e.g. the damaged degree of DNA, the contents of phycoerythrin, chlorophyll a and MDA and the concentration of UV protected compound-MAAs )of the algae were measured. From the results, the damages of UV-B radiation were assayed from apparent effects to internal, and the protection mechanism of c.ocellatus.1. Effects of UV-B radiation on the early growth and developments of tetraspores and carposporesThe results showed that UV-B radiation had some significantly effects on the development and many Physiology and Biochemistry Values of tetraspores and carpospores. High dose of UV-B radiation could cause growth tardiness, indistinct borders, loosing and irregularity of algae cells arrangement and the pigment of the algae were bleached considerably. Further study indicated that low UV-B radiation (36 J·m-2·d-1) showed strongly accelerating effects on the growth of the tetraspores and carpospores, although the concentration of CPDs and MAAs had already increased, phycoerythrin and chlorophyll a contents significantly decreased. When the dose of UV-B radiation was 144 J·m-2·d-1, the photolyase was encouraged which serve as one of the most important enzymes in DNA repair mechanism, consequently the contents of CPDs began to decrease. In the present study, once given UV-B radiation namely the 36 J·m-2·d-1 UV-B radiation experimental groups, the content of phycoerythrin and chlorophyll a were damaged significantly, moreover with the dose of UV-B radiation increasing, the concentration of phycoerythrin reduced gradually. Based on the analyses of liquid chromatography/mass spectrometry (LC/MS), two kinds of MAAs (palythine and asterina-330) were induced by UV-B radiation in tetraspores of c.ocellatus and three kinds of MAAs (palythine, asterina-330 and shinorine) in carpospores. Plenty of MAAs was induced by low dose of UV-B radiation (36 J·m-2·d-1) in tetraspores and carpospores of c.ocellatus, furthermore with the dose of UV-B radiation increased, MAAs were consumed as UV-B absorbing compound and antioxidant, so the contents of MAAs decreased significantly. During the experiments, it is discovered that the carpospores of c.ocellatus were more sensitive to the low dose of UV-B radiation. With the dose of UV-B radiation increased, tetraspores were damaged more serious. It is indicated that tetraspores were more sensitive under the high UV-B radiation dose.2. Effects of different repair conditions on UV-B radiation damage repair in tetraspores and carposporesFor assaying the effects of different repair conditions on UV-B radiation damages repair in tetraspores and carpospores of c.ocellatus, PAR, dark, blue light and red light condition were used to culture the algae after being exposed to UV-B radiation. The results indicated that different repair condition showed different characteristics during the repair process of tetraspores and carpospores. Under low dose of UV-B radiation (36 J·m-2·d-1), tetraspores had the best growth status in red repair experimental groups, but the growth rates of carpospores in PAR repair experimental groups was higher. In addition, PAR played an important role in the repair mechanism of carpospores after being exposed to UV-B radiation. In blue repair experimental groups, the growth of tetraspores and carpospores inferior compare with three other experimental groups. The experiment results also demonstrated that the dark repair mechanism be significantly activated by dark condition, and the photolyase could be encouraged by blue light, as a result the repair efficiency was greatly improved. In PAR and blue repair experimental groups, the contents of phycoerythrin were significantly increased when the UV-B radiation was 36 J·m-2·d-1, then with the dose of UV-B radiation kept on increasing, the concentrations of phycoerythrin decreased significantly. In the present study, dark, blue light and red light repair after UV-B radiation could reduce sensibility of the MAAs synthesis mechanism C. ocellatus tetraspores. The results indicated that PAR which contains various kind of light quality played an important role in the repair mechanism of tetraspores and carpospores after being exposed to UV-B radiation.3. Effects of acute UV-B radiation on young gametophytes and sporophytes of C. ocellatusIn the experiment, young gametophytes and sporophytes of C. ocellatus were used to assay the effects of acute UV-B radiation on gametophytes and sporophytes. Many Physiology and Biochemistry Values (e.g. the contents of CPDs, phycoerythrin, chlorophyll a and the concentration of UV protected compound-MAAs) were measured, in order to study on the changes of several substances in gametophytes and sporophytes as UV-B radiation time prolonging. From the results we could speculate the effects of UV-B radiation on some physiological metabolism process in gametophytes and sporophytes. When UV-B radiation time was 10 min, the contents of CPDs declined by small margin, then with the UV-B radiation time extending, the concentrations of CPDs increased significantly. The results showed that UV-B radiation possessed significantly decreased the pigments contents in young gametophytes and sporophytes of C. ocellatus. With the prolonging of exposure time of UV-B radiation, the contents of phycoerythrin and chlorophyll a reduced significantly. A large number of MAAs was induced by low dose of UV-B radiation, then with the time of UV-B radiation prolonging, the content of MAAs reduced gradually. It is presumed that MAAs was consumingd as UV-B absorbing compound or antioxidant.4. Effects of enhanced UV-B radiation on the developments of gametophytes and sporophytes of C. ocellatusMature gametophytes and sporophytes collected from Taiping Cape, Qingdao, Shandong Province. The effects of UV-B radiation on the growth, physiological and biochemical characteristics were studied by taking pictures on regular and measuring the contents of CPDs, phycoerythrin, chlorophyll a, MDA and MAAs. The purpose of the present experimental work is to study the influence degrees of UV-B radiation on the developments of mature C. ocellatus, and the protection and repair mechanism of the algae. It would appear any phenomenon of abnormity on the algae after being exposed to UV-B radiation. For example, the thallus became thickness, the color turn light (the pigment were bleached seriously), faded in mottling, the thallus borders were indistinct and started to decay seriously and surface of the thallus were rough. Most seriously, the carpostome were bleached severely, and inhibited the growth and multiply of the next generation. The 1st day, the content of CPDs enhanced a bit in 72 J·m-2·d-1 UV-B radiation experimental group. And with the dose of UV-B radiation increased continually, the contents of CPDs decreased first, then increased. The concentrations of phycoerythrin and chlorophyll a could be induced when the dose of UV-B radiation were 72 and 144 J·m-2·d-1. With the dose of UV-B radiation enhanced, the content of MDA increased significantly. Plenty of MAAs could be induced when the dose of UV-B radiation relatively low. The result of study indicates gametophytes of C. ocellatus were more sensitive to UV-B radiation, and more injured after being exposed to UV-B radiation.
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