Temperature thresholds during the rice （Oryza sativa L.） cycle development have been reported to affect plant metabolism Therefore, this study aimed to evaluate the effects of the above-optimal temperature on photos...Temperature thresholds during the rice （Oryza sativa L.） cycle development have been reported to affect plant metabolism Therefore, this study aimed to evaluate the effects of the above-optimal temperature on photosynthetic and morphometric parameters in two contrasting irrigated rice genotypes （BRS Quer^ncia--sensitive and Nagina 22 （N22）~tolerant）. Plants of both genotypes were grown in rhizotrons and always maintained under two temperature conditions： Out--under environmental temperature conditions, and In--rhizotrons inside a plastic structure, which increased the temperature about 3 ~C to 5 ~C above the external one. In the genotype N22, there was an increase （twofold higher） in CO2 assimilation in plants cultivated under elevated temperature （In）. In BRS Quer^ncia, the stomatal conductance （gs） and transpiration rate （E） decreased upon high temperature. The rise in the temperature also negatively impacted in the modulated fluorescence parameters in both genotypes. Increases in root dry weight （RDW） and shoot dry weight （SDW） were also observed in the genotype N22 when compared to BRS Quer^ncia upon temperature rise. In general, the N22 genotype showed greater response to the above-optimal temperature due to its intrinsic thermotolerance traits over BRS Quer^ncia. Thus, N22 appeared as a potential donor of heat tolerance genes aiming to obtain new cultivar to face current global wanning.展开更多
Butia palm forests are considered unique due to their aesthetic value, high biodiversity level and historical, archaeological and cultural value. The lack of regeneration of butia palms caused by cattle overgrazing an...Butia palm forests are considered unique due to their aesthetic value, high biodiversity level and historical, archaeological and cultural value. The lack of regeneration of butia palms caused by cattle overgrazing and natural grasslands replacement by agriculture endangers these palm forests. The aim of this work is to provide information for the proposal of a conservation area in this rural landscape within the framework of sustainable development. This work was developed within the context of a Geographic Information System with thematic information on palm forest density levels, soils, land use aptitude and rural registers. Field surveys were conducted to record the presence of plant species and genetic resources in different vegetation units. The main category of soil cover was natural grasslands, followed by native forests, wetlands and palm forests. Palm forests grow mainly on soil units with poor to rather poor drainage and on arable or non-arable lands under special conditions. We identified 212 farms where the palm forest is found, a high diversity of vegetation units, the presence of 302 native taxa of plants and a significant number of plant genetic resources for various uses. For the designation of a conservation area, we propose 20 priority farms that will ensure that palm forests are well represented regarding ecosystem diversity. We consider the creation of a Protected Landscape, a State Park or a GIAHS to be the best alternatives so as to protect this unique multifunctional landscape.展开更多
文摘Temperature thresholds during the rice （Oryza sativa L.） cycle development have been reported to affect plant metabolism Therefore, this study aimed to evaluate the effects of the above-optimal temperature on photosynthetic and morphometric parameters in two contrasting irrigated rice genotypes （BRS Quer^ncia--sensitive and Nagina 22 （N22）~tolerant）. Plants of both genotypes were grown in rhizotrons and always maintained under two temperature conditions： Out--under environmental temperature conditions, and In--rhizotrons inside a plastic structure, which increased the temperature about 3 ~C to 5 ~C above the external one. In the genotype N22, there was an increase （twofold higher） in CO2 assimilation in plants cultivated under elevated temperature （In）. In BRS Quer^ncia, the stomatal conductance （gs） and transpiration rate （E） decreased upon high temperature. The rise in the temperature also negatively impacted in the modulated fluorescence parameters in both genotypes. Increases in root dry weight （RDW） and shoot dry weight （SDW） were also observed in the genotype N22 when compared to BRS Quer^ncia upon temperature rise. In general, the N22 genotype showed greater response to the above-optimal temperature due to its intrinsic thermotolerance traits over BRS Quer^ncia. Thus, N22 appeared as a potential donor of heat tolerance genes aiming to obtain new cultivar to face current global wanning.
文摘Butia palm forests are considered unique due to their aesthetic value, high biodiversity level and historical, archaeological and cultural value. The lack of regeneration of butia palms caused by cattle overgrazing and natural grasslands replacement by agriculture endangers these palm forests. The aim of this work is to provide information for the proposal of a conservation area in this rural landscape within the framework of sustainable development. This work was developed within the context of a Geographic Information System with thematic information on palm forest density levels, soils, land use aptitude and rural registers. Field surveys were conducted to record the presence of plant species and genetic resources in different vegetation units. The main category of soil cover was natural grasslands, followed by native forests, wetlands and palm forests. Palm forests grow mainly on soil units with poor to rather poor drainage and on arable or non-arable lands under special conditions. We identified 212 farms where the palm forest is found, a high diversity of vegetation units, the presence of 302 native taxa of plants and a significant number of plant genetic resources for various uses. For the designation of a conservation area, we propose 20 priority farms that will ensure that palm forests are well represented regarding ecosystem diversity. We consider the creation of a Protected Landscape, a State Park or a GIAHS to be the best alternatives so as to protect this unique multifunctional landscape.
