RESUMEN
The remobilization of cadmium (Cd) from shoots to grain is the key process to determine the Cd accumulation in grain. The apoplastic pH of plants is an important factor and signal in influencing on plant responding to environmental variation and inorganic elements uptake. It is proposed that pH of rice plants responds and influences on Cd remobilization from shoots to grain when rice is exposed to Cd stress. The results of hydroponic experiment showed that: pH of the rice leaf vascular bundles among 3 cultivars was almost increased, pH value of 1 cultivar was slightly increasing when rice plants were treated with Cd. The decrease degree of H+ concentration in leaf vascular bundles was different among cultivars. The cultivar with higher decreasing in H+ concentration, showed higher Cd transfer efficiency from shoots to grain. The H+ concentration of leaf vascular bundles under normal condition was negatively correlated to cadmium accumulation in leaf. Moreover, pH change was related to Cd accumulation in shots and remobilization from shoots to grain. Uncovering the role of pH response is a key component for the understanding Cd uptake and remobilization mechanism for rice production.
Asunto(s)
Cadmio/metabolismo , Grano Comestible/metabolismo , Oryza/metabolismo , Brotes de la Planta/metabolismo , Haz Vascular de Plantas/química , Contaminantes del Suelo/metabolismo , Transporte Biológico , Cadmio/análisis , Grano Comestible/química , Concentración de Iones de Hidrógeno , Hidroponía , Modelos Teóricos , Oryza/química , Hojas de la Planta/química , Brotes de la Planta/química , Contaminantes del Suelo/análisis , Especificidad de la EspecieRESUMEN
In a pot experiment, hyperaccumulator Sedum plumbizincicola and low-cadmium accumulating Oryza sativa cultivar "Zhongxiang No. 1" were planted in rotation on a heavy metals-polluted soil, and calcium magnesium phosphate (Ca-P) and rock phosphate (P-R) were amended, aimed to study the effects of the rotation and phosphate amendment on the growth of the two plants and the zinc- and cadmium accumulation in their shoots. After the amendment of 50 g P-R x kg(-1), the Zn and Cd uptake by S. plumbizincicola was 11.5 mg x pot(-1) and 0 x 79 mg x pot(-1), respectively, being significantly higher than that after the amendment of 4 g Ca-P x kg(-1). After the planting of S. plumbizincicola, the Zn and Cd concentrations in "Zhongxiang No. 1" increased, but the amendment of Ca-P decreased the accumulation of Zn and Cd in rice shoot significantly. The rotation with S. plumbizincicola and the amendment of Ca-P and P-R could immobilize the Zn and Cd in the contaminated soil as indicated by the quantitative change of NH4OAc-extractable Cd and Zn, and the efficiency of amendment with Ca-P was better than that of amendment with P-R. Field trial showed that amendment with Ca-P could not only increase the rice yield, but also reduce the Zn and Cd accumulation in rice shoot to a certain extent.
Asunto(s)
Cadmio/metabolismo , Oryza/metabolismo , Fosfatos/farmacología , Sedum/metabolismo , Contaminantes del Suelo/metabolismo , Zinc/metabolismo , Absorción , Agricultura/métodos , Calcio/farmacología , Magnesio/farmacología , Oryza/crecimiento & desarrollo , Sedum/crecimiento & desarrolloRESUMEN
Using rice variety DI508 as test material, a field experiment of different seeding dates and a test with plant growth chamber were conducted to study the dynamic changes of rice tiller angle under effects of different photoperiod and effective accumulated temperature. Under field condition, the tiller angle of DI508 plants changed gradually into erect after 10-15 days of photoperiod becoming shorter (since the Summer Solstice on 21st June), irrespective of seeding dates (4th April, 5th May, and 4th June). Under controlled photoperiod, the tiller angle changed in the same way as in the field. Shorter lighting treatment (10 hours) advanced the tiller angle change, while longer lighting treatment (14 hours) delayed the change. Effective accumulated temperature had no effects on the tiller angle change of DI508.
Asunto(s)
Oryza/fisiología , Fotoperiodo , Temperatura , Oryza/genética , Oryza/crecimiento & desarrolloRESUMEN
A field experiment was conducted to study the effects of rice-duck farming on the related biotic populations in paddy field. The results showed that rice-duck farming had greater effects on the occurrence and damage of pests, pathogens and weeds, as well as the amount of pests' natural enemies in paddy field. The population of rice planthopper and leafhopper decreased by 64.8% and 78.5% after 12 and 42 days of duck-release, and the weeds decreased by 67.7% and 98.1% after 15 and 45 days of duck-release, respectively, compared with the control. The sheath blight index at the maximum tillering stage and full-heading stage in the rice-duck plots were 40.4% and 62.0% lower than those in the control plot, respectively. The population of spiders in duck-released field was increased obviously, which in turn decreased the damage of rice pests.
Asunto(s)
Agricultura/métodos , Patos/fisiología , Oryza/parasitología , Poaceae/fisiología , Alimentación Animal , Animales , Patos/crecimiento & desarrollo , Ecosistema , Oryza/crecimiento & desarrollo , Control Biológico de Vectores/métodosRESUMEN
A recombinant inbred lines (RILs) population derived from a cross between Zhenshan97B and Miyang46 was used for detecting QTLs with additive effects and additive-by-additive epistasis for rice mesocotyl length. A linkage map consisting of 207 DNA markers,distributing on the 12 chromosomes of rice,was employed for QTL mapping by using software QTL Mapper 1.6 of mixed linear model. Rice mesocotyl length under germination conditions with 4 different FeSO4 concentrations (0, 1.79, 7.16, 14.32 mmol/L) was measured 7 days after planting. A total of 6 QTLs with significant additive effects on chromosome 1, 5 and 9, with variance explained of 3.5%-11.4%, eleven QTLs with significant additive x additive epistatic effects on chromosome 1, 2, 3, 4, 5, 8 were detected, with variance explained of 4.5%-8.1%. In addition, one QTL for environmental interaction (Fe2+ -concentrations) was detected.