The study aims to solve the problems of late transplanting rice with differ- ent seedling ages at the lower reaches of Yangtze River. We selected six varieties of different thermal and photo-response characteristics a...The study aims to solve the problems of late transplanting rice with differ- ent seedling ages at the lower reaches of Yangtze River. We selected six varieties of different thermal and photo-response characteristics as the test material to study the effect of different seedling ages on growth and yield of rice. The results showed that growing period of thermal-response rice was delayed by long seedling age, but less affected by the impact of photo-response rice; the yield of later thermal-re- sponse varieties with 25 days and 30 days seedling ages was significantly reduced. In contrast, the yield of early thermal-response varieties and later photo-response varieties were significantly reduced with 30 days seedling age. The optimal trans- planting seedling age was 15 days of thermal-response rice, while photo-response rice was 20 days. The thermal-response rice should be selected as early maturing varieties, while the photo-response rice could be selected as late maturing varieties for high yield.展开更多
Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorte...Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorter growing season experienced by a maternal jointed goatgrass plant similarly affected seedling vigor in the progeny. Seed mass, percent germination, emergence, seedling height and biomass, including roots, were recorded or evaluated on progeny that were produced from three jointed goatgrass populations grown under a long or short growing season in a common garden experiment in eastern Oregon, an area where jointed goatgrass is known to commonly infest natural resources, including winter wheat. Seeds produced under a shorter growing season weighed less, were slower to germinate, and displayed lower percent germination compared with seeds produced under a long growing season. Seedlings from a short growing season were slower to emerge, and produced less shoot biomass compared to seedlings produced under a long growing season. Seedling roots and shoots were shorter when seeds were produced under a short growing season. A shorter growing season negatively affected jointed goatgrass seedling vigor. If resources for jointed goatgrass management are limited, strategies should focus on controlling plants that emerge in the fall, because they have the potential to produce more vigorous seedlings compared to plants that emerge in late winter or early spring.展开更多
Effects of 2,4-D on seedling growth and chromosomal abnormalities were studied in Triticum aestivum and Phalaris minor.Seeds were soaked at different concentrations of 2,4-D (0.01%,0.1%,1.0%) for 4,8,12 and 16 hours.2...Effects of 2,4-D on seedling growth and chromosomal abnormalities were studied in Triticum aestivum and Phalaris minor.Seeds were soaked at different concentrations of 2,4-D (0.01%,0.1%,1.0%) for 4,8,12 and 16 hours.2,4-D suppressed the germination more severely in P.minor than in T.aestivum.Shoot and root length was retarded with the increase of concentration and time of treatment in both species.Generally radical was more negatively affected than coleoptile and emergence of radical was not observed at 1.0% concentration at 8,12,and 16 hours of treatment in T.aestivum while in P.minor there was a total lack of radical emergence at 1.0% concentration for all durations of treatment.Stiff and curled roots and undifferentiated callus like scutellar tissues were observed in T.aestivum,while in P.minor the coleoptile obtained was lean,pale green in colour and was lying flat on filter paper.Mitotic index decreased,while chromosomal abnormalities,bridges and laggards were increased with the increase of concentration and soaking time however,laggards were not observed in T.aestivum.Clumping and chain formation of chromosomes at metaphase was also noticed in P.minor.展开更多
基金Supported by State Science and Technology Supporting Program(2012BAD07B02)Special Program for Technological Development of Scientific Research Institute of Science and Technology Department(2013EG134237)"Three Rural and Six Party"Science and Technology Cooperation Projects of Zhejiang Province(SN201206)~~
文摘The study aims to solve the problems of late transplanting rice with differ- ent seedling ages at the lower reaches of Yangtze River. We selected six varieties of different thermal and photo-response characteristics as the test material to study the effect of different seedling ages on growth and yield of rice. The results showed that growing period of thermal-response rice was delayed by long seedling age, but less affected by the impact of photo-response rice; the yield of later thermal-re- sponse varieties with 25 days and 30 days seedling ages was significantly reduced. In contrast, the yield of early thermal-response varieties and later photo-response varieties were significantly reduced with 30 days seedling age. The optimal trans- planting seedling age was 15 days of thermal-response rice, while photo-response rice was 20 days. The thermal-response rice should be selected as early maturing varieties, while the photo-response rice could be selected as late maturing varieties for high yield.
文摘Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorter growing season experienced by a maternal jointed goatgrass plant similarly affected seedling vigor in the progeny. Seed mass, percent germination, emergence, seedling height and biomass, including roots, were recorded or evaluated on progeny that were produced from three jointed goatgrass populations grown under a long or short growing season in a common garden experiment in eastern Oregon, an area where jointed goatgrass is known to commonly infest natural resources, including winter wheat. Seeds produced under a shorter growing season weighed less, were slower to germinate, and displayed lower percent germination compared with seeds produced under a long growing season. Seedlings from a short growing season were slower to emerge, and produced less shoot biomass compared to seedlings produced under a long growing season. Seedling roots and shoots were shorter when seeds were produced under a short growing season. A shorter growing season negatively affected jointed goatgrass seedling vigor. If resources for jointed goatgrass management are limited, strategies should focus on controlling plants that emerge in the fall, because they have the potential to produce more vigorous seedlings compared to plants that emerge in late winter or early spring.
文摘Effects of 2,4-D on seedling growth and chromosomal abnormalities were studied in Triticum aestivum and Phalaris minor.Seeds were soaked at different concentrations of 2,4-D (0.01%,0.1%,1.0%) for 4,8,12 and 16 hours.2,4-D suppressed the germination more severely in P.minor than in T.aestivum.Shoot and root length was retarded with the increase of concentration and time of treatment in both species.Generally radical was more negatively affected than coleoptile and emergence of radical was not observed at 1.0% concentration at 8,12,and 16 hours of treatment in T.aestivum while in P.minor there was a total lack of radical emergence at 1.0% concentration for all durations of treatment.Stiff and curled roots and undifferentiated callus like scutellar tissues were observed in T.aestivum,while in P.minor the coleoptile obtained was lean,pale green in colour and was lying flat on filter paper.Mitotic index decreased,while chromosomal abnormalities,bridges and laggards were increased with the increase of concentration and soaking time however,laggards were not observed in T.aestivum.Clumping and chain formation of chromosomes at metaphase was also noticed in P.minor.
