Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity....Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity.This report investigated the effects of cold stress and supplementalγ-aminobutyric acid(GABA)under cold stress on nitrogen metabolism in rice seedlings.Cold stress resulted in a greater increase in the transformation to NH_(4)^(+)by nitrate reductase(NR)in roots,it further resulted in lower levels of NO_(3)^(-)content in roots,weakened glutamine glutamate(GOGAT/GS)pathway and elevated glutamate dehydrogenase(GDH)pathway of rice seedlings.Whereas,compared with cold stress,supplementation of GABA(2.5 mmol·L^(-1))could increase relative water content(79.43%)and biomass(34.15%)of rice seedlings.GABA could act as an amplifier of stress signal conduction/transduction to increase NR activity and promote NO_(3)^(-)assimilation in leaves.In addition,GABA elicited the Ca^(2+)signaling pathway which could promote the GDH pathway and GABA shunt,increase the activities of GS and GDH,and the expression of OsGAD2 and OsGDH family.The GABA might increase the ratio of the Glu family and avoid NH4+toxicity in order to raise the concentration of organic compounds and alleviate the harmful consequences of cold stress.Based on these observations,this study proposed that GABA mediated cold tolerance in rice seedlings by activating Ca^(2+)burst and subsequent crosstalk among Ca^(2+)signaling,GDH pathway and GABA shunt.展开更多
文摘利用Google Earth Engine(GEE)云计算平台,基于改进的CASA模型对鄂尔多斯2001—2020年间的植被净初级生产力(NPP)进行估算,并运用Sen斜率分析和MK趋势分析方法对NPP的时空变化进行深入分析,同时估算了其固碳能力。结果表明:(1)鄂尔多斯2001—2020年间植被NPP呈现明显的季节变化,最高值出现在7—8月,年平均NPP为78.04 g C·m^(-2)·a^(-1),整体呈波动上升趋势。(2)在空间分布上,NPP存在明显的异质性,东北部较高,西北部较低,高值区集中在达拉特旗和准格尔旗,低值区则主要分布在杭锦旗。(3)生态工程的实施与NPP变化并不完全同步,整体呈现先慢后快的特点,大部分区域在2011年后NPP变化速率显著提升,但杭锦旗等生态环境恶劣地区的改善较慢,有一定滞后性。(4)鄂尔多斯固碳量在2011年呈大面积负值,但2020年固碳量空间异质性显著增强,东部较高、西部较低,杭锦旗西部恢复仍需加强,而达拉特旗固碳能力显著提升。
基金Supported by the National Natural Science Foundation of China(32301935)the Heilongjiang Province Natural Science Foundation Project(LH2020C005)+1 种基金the Postdoctoral Fund to Research Start-up of Heilongjiang Province(LBH-Q21077)Heilongjiang Province Applied Technology Research and Development Plan Project(GA20B101)。
文摘Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity.This report investigated the effects of cold stress and supplementalγ-aminobutyric acid(GABA)under cold stress on nitrogen metabolism in rice seedlings.Cold stress resulted in a greater increase in the transformation to NH_(4)^(+)by nitrate reductase(NR)in roots,it further resulted in lower levels of NO_(3)^(-)content in roots,weakened glutamine glutamate(GOGAT/GS)pathway and elevated glutamate dehydrogenase(GDH)pathway of rice seedlings.Whereas,compared with cold stress,supplementation of GABA(2.5 mmol·L^(-1))could increase relative water content(79.43%)and biomass(34.15%)of rice seedlings.GABA could act as an amplifier of stress signal conduction/transduction to increase NR activity and promote NO_(3)^(-)assimilation in leaves.In addition,GABA elicited the Ca^(2+)signaling pathway which could promote the GDH pathway and GABA shunt,increase the activities of GS and GDH,and the expression of OsGAD2 and OsGDH family.The GABA might increase the ratio of the Glu family and avoid NH4+toxicity in order to raise the concentration of organic compounds and alleviate the harmful consequences of cold stress.Based on these observations,this study proposed that GABA mediated cold tolerance in rice seedlings by activating Ca^(2+)burst and subsequent crosstalk among Ca^(2+)signaling,GDH pathway and GABA shunt.
