OBJECTIVETo reveal the effects of UV-B radiation on the growth of medical plant Mentha piperita, simulate an enhanced UV-B radiation and evaluate intensity of radiation on the photosynthesis of M. piperita.

METHODThree different levels of UV-B radiation were set in the experiment which included: natural light control (0 W x m(-2)), light UV-B radiation stress (0.15 W x m(-2)) and heavy UV-B radiation stress (0.35 W x m(-2)). The chloroplast ultrastructure, photosynthesis indexes and chlorophyll fluorescence parameters of the M. piperita were observed under the three treatments.

RESULTAlthough the chloroplast ultrastructure was destroyed to some degree under the light UV-B radiation stress, F(v)/(F)m, F(v)/F(o), qP, phiPS II and ETR could resume to the comparative level of natural light control. At the same time, qN increased firstly and decreased thereafter. But under the high strength UV-B radiation stress, the photosynthetic structures were badly destroyed, which could not recover through protecting mechanism by itself.

CONCLUSIONIt was showed that M. piperita was able to protect photosynthetic structures by increasing respiration and dissipation when photosynthetic capacity reduced under light UV-B radiation stress. It is demonstrated that M. piperita has high adaptation to light UV-B radiation stress, which is kind of promising medical plant for area with higher UV-B radiation.

Chlorophyll ; metabolism ; Chloroplasts ; metabolism ; radiation effects ; ultrastructure ; Mentha piperita ; metabolism ; radiation effects ; ultrastructure ; Photosynthesis ; radiation effects ; Ultraviolet Rays

OBJECTIVETo study the mutagenic effect of gamma-rays on Coix lacryma-jobi var. ma-yuen.

METHODPhysiological and mutagenic effects of gamma-rays on C. lacryma-jobi var. ma-yuen dormant seeds were studied. The germination percentage, seeding survival, seeding height and root length of M1 plants and the frequency of chlorophyll mutation in M2 generation were selected as criteria.

RESULTThe gamma-rays showed obvious inhibitory action to the seedling growth, and a strong ability in inducing the chlorophyll mutation.

CONCLUSIONThe gamma-rays is one kind of C. lacryma-jobi var. ma-yuen effective mutagen. The appropriate dose of gamma-rays is 450 Gy for C. lacryma-jobi var. ma-yuen dormant seeds.

Chlorophyll ; metabolism ; Chloroplasts ; genetics ; metabolism ; radiation effects ; Cobalt Radioisotopes ; Coix ; genetics ; growth & development ; radiation effects ; Gamma Rays ; Germination ; genetics ; physiology ; radiation effects ; Inclusion Bodies ; Mutagenesis ; radiation effects ; Mutation ; radiation effects ; Plant Roots ; genetics ; growth & development ; radiation effects ; Radiation Dosage ; Seedlings ; genetics ; growth & development ; radiation effects ; Seeds ; genetics ; growth & development ; radiation effects

Under different red (R):blue (B) photon flux ratios, the growth performance of rapeseed (Brassica napus L.) is significantly different. Rapeseed under high R ratios shows shade response, while under high B ratios it shows sun-type morphology. Rapeseed under monochromatic red or blue light is seriously stressed. Transcriptomic and proteomic methods were used to analyze the metabolic pathway change of rapeseed (cv. "Zhongshuang 11") leaves under different R:B photon flux ratios (including 100R:0B%, 75R:25B%, 25R:75B%, and 0R:100B%), based on digital gene expression (DGE) and two-dimensional gel electrophoresis (2-DE). For DGE analysis, 2054 differentially expressed transcripts (|log₂(fold change)|≥1, q<0.005) were detected among the treatments. High R ratios (100R:0B% and 75R:25B%) enhanced the expression of cellular structural components, mainly the cell wall and cell membrane. These components participated in plant epidermis development and anatomical structure morphogenesis. This might be related to the shade response induced by red light. High B ratios (25R:75B% and 0R:100B%) promoted the expression of chloroplast-related components, which might be involved in the formation of sun-type chloroplast induced by blue light. For 2-DE analysis, 37 protein spots showed more than a 2-fold difference in expression among the treatments. Monochromatic light (ML; 100R:0B% and 0R:100B%) stimulated accumulation of proteins associated with antioxidation, photosystem II (PSII), DNA and ribosome repairs, while compound light (CL; 75R:25B% and 25R:75B%) accelerated accumulation of proteins associated with carbohydrate, nucleic acid, amino acid, vitamin, and xanthophyll metabolisms. These findings can be useful in understanding the response mechanisms of rapeseed leaves to different R:B photon flux ratios.
Brassica napus/radiation effects* ; Brassica rapa/radiation effects* ; Carbon/chemistry* ; Chloroplasts/radiation effects* ; Computational Biology ; Electrophoresis, Gel, Two-Dimensional ; Gene Expression Regulation, Plant/radiation effects* ; Image Processing, Computer-Assisted ; Light ; Mass Spectrometry ; Metabolic Networks and Pathways ; Nitrogen/chemistry* ; Photons ; Photosystem II Protein Complex/genetics* ; Plant Leaves/radiation effects* ; Plant Proteins/genetics* ; Proteome ; Ribosomes ; Transcription, Genetic ; Transcriptome