Physiological and Molecular Responses in Rice, Weedy Rice and Barnyardgrass Exposed to Supra-Optimal Temperatures

ABSTRACT: The global temperature to rise 0.3 to 4.8 oC to century. Supra-optimal temperatures can affect plants at different organizational levels, causing morphological, physiological, biochemical and gene expression alterations. Rice, weedy rice, and barnyardgrass may to response differently when subjected to supra-optimal temperatures. Thus, the aimed at determining the physiological response and expression of the genes APX2, HSP24.15 e HSP71.10 in rice, weedy rice, and barnyardgrass when in to supra-optimal temperatures. A greenhouse experiment was conducted in randomized complete desing with four repetitions, with a factorial combination of temperature x plantas, where: factor A consisted of two temperatures (25 oC and 40 oC); and factor B of three plants [rice (Oryza sativa cv. Puitá INTA-CL), weedy rice (Oryza spp.), and barnyardgrass (Echinochloa spp.)]. The 40 oC temperature, in general, caused a reduction in the photosynthesis parameters and in the protein content, and increased the oxidative stress in C3 plants; no damage was observed in the C4 plant subjected to this temperature. In response to the supra-optimal temperatures, rice and weedy rice increased of APX and SOD activity and the expression of OsAPX2, OsHSP24.15 and OsHSP71.10 genes. Barnyardgrass exposed to supra-optimal temperature do not modify the activity of its antioxidant system and increased the OsHSP71.10 gene expression.

摘要：本世纪全球气温将上升0.3至4.8摄氏度。亚最优高温可从不同组织层面影响植物，引发其形态、生理、生化及基因表达层面的改变。水稻、杂草稻与稗草在遭受亚最优高温胁迫时，其响应模式可能存在差异。因此本研究旨在明确水稻、杂草稻及稗草在亚最优高温环境下的生理响应，以及抗坏血酸过氧化物酶2（APX2）、热休克蛋白24.15（HSP24.15）与热休克蛋白71.10（HSP71.10）这三个基因的表达情况。本研究采用完全随机区组设计开展温室盆栽试验，设置4次重复，采用温度×植物的双因素析因处理方案：因素A包含两个温度梯度（25℃与40℃）；因素B包含3种供试植物，即水稻（Oryza sativa cv. Puitá INTA-CL）、杂草稻（Oryza spp.）以及稗草（Echinochloa spp.）。总体而言，40℃高温会降低C3植物的光合参数与蛋白质含量，并加剧其氧化胁迫；该温度对供试C4植物未造成明显损伤。在亚最优高温胁迫下，水稻与杂草稻的抗坏血酸过氧化物酶（APX）、超氧化物歧化酶（SOD）活性，以及OsAPX2、OsHSP24.15、OsHSP71.10基因的表达量均显著提升。而稗草在遭受亚最优高温时，其抗氧化系统活性未发生显著变化，但OsHSP71.10基因的表达量有所上调。