[ Objective] This study aimed to investigate the biological effects of laser-induced mutation on fibrous roots of yellow skin onion. [ Method] Wet seeds of two yellow skin onion cultivars were irradiated by CO2 laser ...[ Objective] This study aimed to investigate the biological effects of laser-induced mutation on fibrous roots of yellow skin onion. [ Method] Wet seeds of two yellow skin onion cultivars were irradiated by CO2 laser and He-Ne laser at three dosage levels separately. A randomized complete block design with three replications was adopted. The biological effects of laser-induced mutation on fibrous roots of Ll-generation yellow skin onion were investigated with biostatistics and physiological and biochemical methods. [Result] Significant variations in the biological effects caused by various laser treatments were observed in the length, quantity, fresh weight and activity of onion fibrous roots. Specifically, the variation in fibrous root length induced by different types of laser reached 5% significance level; significant variation was observed in fibrous roots of different onion cultivars induced by laser, while the variation among each treatment did not reach 5% sig- nifieance level ; the variation in fibrous root quantity induced by different dosage levels of laser reached 5% significance level ; laser radiation showed stimulating effect on root activity of onion. [ Conclusion] This study provided reference for laser-induced breeding of yellow skin onion.展开更多
Fine particles in seawater commonly form large porous aggregates. Aggregate density and settling velocity determine the behavior of this suspended particulate matter(SPM) within the water column.However, few studies o...Fine particles in seawater commonly form large porous aggregates. Aggregate density and settling velocity determine the behavior of this suspended particulate matter(SPM) within the water column.However, few studies of aggregate particles over a continental shelf have been undertaken. In our case study, properties of aggregate particles, including size and composition, over the continental shelf of the North Yellow Sea were investigated. During a scienti?c cruise in July 2016, in situ ef fective particle size distributions of SPM at 10 stations were measured, while temperature and turbidity measurements and samples of water were obtained from surface, middle, and bottom layers. Dispersed and inorganic particle size distributions were determined in the laboratory. The in situ SPM was divided into(1) small particles(<32 μm),(2) medium particles(32–256 μm) and(3) large particles(>256 μm). Large particles and medium particles dominated the total volume concentrations(VCs) of in situ SPM. After dispersion, the VCs of medium particles decreased to low values(<0.1 μL/L). The VCs of large particles in the surface and middle layers also decreased markedly, although they had higher peak values(0.1–1 μL/L). This suggests that almost all in situ medium particles and some large particles were aggregated, while other large particles were single particles. Correlation analysis showed that primary particles <32 μm in?uenced the formation of these aggregates. Microscopic examination revealed that these aggregates consisted of both organic and inorganic ?ne particles, while large particles were mucus-bound organic aggregates or individual plankton.The vertical distribution of coarser particles was clearly related to water strati?cation. Generally, medium aggregate particles were dominant in SPM of the bottom layer. A thermocline blocked resuspension of?ne material into upper layers, yielding low VCs of medium-sized aggregate particles in the surface layer.Abundant large biogenic particles were present in both surface and middle layers.展开更多
基金Supported by Natural Science Foundation of Sichuan Education Department(2008ZA033)
文摘[ Objective] This study aimed to investigate the biological effects of laser-induced mutation on fibrous roots of yellow skin onion. [ Method] Wet seeds of two yellow skin onion cultivars were irradiated by CO2 laser and He-Ne laser at three dosage levels separately. A randomized complete block design with three replications was adopted. The biological effects of laser-induced mutation on fibrous roots of Ll-generation yellow skin onion were investigated with biostatistics and physiological and biochemical methods. [Result] Significant variations in the biological effects caused by various laser treatments were observed in the length, quantity, fresh weight and activity of onion fibrous roots. Specifically, the variation in fibrous root length induced by different types of laser reached 5% significance level; significant variation was observed in fibrous roots of different onion cultivars induced by laser, while the variation among each treatment did not reach 5% sig- nifieance level ; the variation in fibrous root quantity induced by different dosage levels of laser reached 5% significance level ; laser radiation showed stimulating effect on root activity of onion. [ Conclusion] This study provided reference for laser-induced breeding of yellow skin onion.
基金Supported by the National Natural Science Foundation of China(No.41476045)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11030103)
文摘Fine particles in seawater commonly form large porous aggregates. Aggregate density and settling velocity determine the behavior of this suspended particulate matter(SPM) within the water column.However, few studies of aggregate particles over a continental shelf have been undertaken. In our case study, properties of aggregate particles, including size and composition, over the continental shelf of the North Yellow Sea were investigated. During a scienti?c cruise in July 2016, in situ ef fective particle size distributions of SPM at 10 stations were measured, while temperature and turbidity measurements and samples of water were obtained from surface, middle, and bottom layers. Dispersed and inorganic particle size distributions were determined in the laboratory. The in situ SPM was divided into(1) small particles(<32 μm),(2) medium particles(32–256 μm) and(3) large particles(>256 μm). Large particles and medium particles dominated the total volume concentrations(VCs) of in situ SPM. After dispersion, the VCs of medium particles decreased to low values(<0.1 μL/L). The VCs of large particles in the surface and middle layers also decreased markedly, although they had higher peak values(0.1–1 μL/L). This suggests that almost all in situ medium particles and some large particles were aggregated, while other large particles were single particles. Correlation analysis showed that primary particles <32 μm in?uenced the formation of these aggregates. Microscopic examination revealed that these aggregates consisted of both organic and inorganic ?ne particles, while large particles were mucus-bound organic aggregates or individual plankton.The vertical distribution of coarser particles was clearly related to water strati?cation. Generally, medium aggregate particles were dominant in SPM of the bottom layer. A thermocline blocked resuspension of?ne material into upper layers, yielding low VCs of medium-sized aggregate particles in the surface layer.Abundant large biogenic particles were present in both surface and middle layers.
