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41.
淹水胁迫对南五味子和海南红豆幼苗光合特性的影响   总被引:1,自引:0,他引:1  
对南五味子和海南红豆的1年生实生苗在不同淹水时间下的叶片的光合特性进行了研究。结果表明:随着淹水时间的持续,南五味子幼苗的净光合速率(Pn)小幅波动后升高,而气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)先降后升,至淹水20 d时各指标均高于对照;海南红豆幼苗的Pn、Gs、Ci、Tr先降后升,至淹水20 d没有恢复到对照水平;2种幼苗的气孔限制值(Ls)均为先升高后下降;南五味子和海南红豆都有一定的抗涝性,前者具有更强的耐淹水能力。  相似文献   
42.
水淹胁迫对紫穗槐生长及营养元素积累的影响   总被引:1,自引:0,他引:1  
通过对不同水淹条件下紫穗槐(Amorpha fruticosa)植株营养生长及各组织中营养元素积累量的分析,发现紫穗槐在表面水淹条件下根系浅生化,半水淹条件下茎根生长不定根,近全淹条件下先生长茎后生出不定根来适应水淹胁迫。3个水淹处理组植株对氮、磷、钙、铁及锰的吸收表现为增益;对铜的吸收表现为降低;改变氮、磷、钙、锌和铜的分配以适应水淹逆境,均与对照组植株存在明显差异(P<0.05)。所有处理各营养元素的积累量均不低于植物正常生长水平,营养生长指标未见严重缺素症,表明紫穗槐可针对不同水淹条件选择最有效节能的适应机制,是优良的抗涝灌木种。  相似文献   
43.
旱涝交替胁迫对水稻荧光参数与光合特性的影响   总被引:1,自引:0,他引:1  
为探明控制灌排条件下旱涝交替胁迫对水稻不同生育阶段荧光参数和光合特性的影响,以农田水位为调控技术指标,采用蒸渗测坑进行水稻栽培试验,在分蘖期、拔节孕穗期、抽穗开花期、乳熟期分别设置先旱后涝胁迫(HZL)、先涝后旱胁迫(LZH)2种旱涝交替胁迫模式,测定叶片相对叶绿素含量(SPAD)、主要荧光参数及光合指标的变化。结果表明,旱涝交替胁迫会减少SPAD,其中HZL处理产生的抑制作用更强;分蘖期、拔节孕穗期旱涝交替胁迫光能转化效率、光化学淬灭系数、最大潜在电子传输速率、光饱和点、净光合速率、潜在水分利用效率等荧光参数和光合指标可以恢复甚至超过对照水平,而在抽穗开花期、乳熟期产生不可逆的影响;旱涝交替胁迫下蒸腾速率、气孔导度分别在分蘖期、乳熟期受到抑制,拔节孕穗期得到促进;HZL处理提高了非光化学淬灭系数,其他主要荧光参数和光合指标HZL低于LZH处理。水稻分蘖期、拔节孕穗期LZH处理对光合作用的补偿作用更大,抽穗开花期、乳熟期HZL处理对光合作用的抑制作用较LZH处理更明显,因此,在水稻生育后期应尽量避免重度的旱涝交替胁迫,尤其要避免发生旱涝急转。  相似文献   
44.
【目的】探讨不同程度涝渍胁迫对桢楠幼树不同功能根系生理生化特性的影响,为桢楠苗圃水分管理及造林地的选择提供理论依据。【方法】以3年生桢楠幼树为研究对象,进行盆栽渍水处理,试验设对照(CK,不进行水淹)、轻度渍水(H5,淹水深5 cm)、中度渍水(H10,淹水深10 cm)、重度渍水(H15,淹水深15 cm)和完全渍水(H20,淹水深25 cm)5个处理,在处理第51天(H20处理叶片出现萎蔫)时,测定桢楠幼树吸收根和运输根的生长及生理生化指标。【结果】(1)除对照(CK)和完全渍水(H20)处理外,涝渍胁迫均可使桢楠幼树产生不定根,且胁迫程度越重新生不定根越少。(2)相较于CK,运输根根系活力在渍水胁迫下显著降低(P0.05), H5、H10、H15和H20处理分别降低45.77%,74.58%,75.67%和90.72%;而吸收根则在胁迫程度重于中度渍水后才出现显著降低的趋势(P0.05),在H20处理下降幅最大,相较于CK降低89.63%。(3)桢楠幼树运输根与吸收根H_2O_2、SP、SS含量及POD活性变化趋势基本一致,均随渍水强度的增加呈现先升高后降低的趋势;MDA含量呈降-升-降的变化趋势;随着渍水强度的增加,桢楠幼树吸收根SOD活性整体呈降低趋势,而运输根的SOD活性则呈先升高后降低的趋势,在H15处理下达最大值,且H5、H10、H15和H20处理分别比CK处理增加9.07%,9.81%,17.89%和8.66%。【结论】轻度渍水能促使桢楠幼树产生大量不定根,在一定程度上抵抗涝渍胁迫对根系的伤害;重度渍水处理后桢楠幼树根系表现出明显的受害症状。受到渍水胁迫时,桢楠幼树运输根表现出更强的抗氧化能力,而吸收根则表现出更强的敏感性和更快的更新能力。  相似文献   
45.
[目的]分析南方农牧交错带降水变化及旱涝多时间尺度特征,为该区旱涝灾害防治决策、牧区生态重建及保护提供科学参考。[方法]基于南方农牧交错带1960—2017年20个气象站点逐月降水量资料,采用标准化降水指数(SPI)、反距离权重插值、M-K突变检验等方法对南方农牧交错带近58 a的降水特征及旱涝灾害时空格局进行研究。[结果]①近58 a以来南方农牧交错带年平均降水量以3.98 mm/10 a的速率在增加,降水主要集中在夏季,用M-K方法检测出该区域年平均降水量在1990年发生突变;②受气候、大气环流、地形、海拔高差、下垫面等因素的影响,降水量在空间分布上以维西—理塘—若尔盖为界,西北部降水量少,东南部降水量多,降水量呈现出由东南向西北递减的趋势;③研究区年降水量的增减变化以松潘—马尔康—新龙—理塘—稻城一线为界线,该线以东地区的年降水量均呈显著增长趋势发展,以西地区的年降水量呈显著减少趋势;[结论]研究区20世纪60—70年代旱灾发生的频率略高,80—90年代涝灾发生的频率较高,2000年以来旱涝灾害呈明显的减弱趋势发展。  相似文献   
46.
A field experiment was performed to explore responses of carbon metabolism, antioxidant system and endogenous hormone content of summer maize hybrids DengHai605 (DH605) and ZhengDan958 (ZD958) to waterlogging at the third leaf stage (V3), the sixth leaf stage (V6) and the 10th day after the tasselling stage (10VT). Results showed that waterlogging significantly decreased the contents of zeatin riboside (ZR), indole‐3‐acetic acid (IAA) and gibberellic acid (GA), compared to those of CK. However, leaf abscisic acid (ABA) content was significantly increased by waterlogging at different stages, with the most significant increase was found in the treatment of waterlogging at V3 (V3‐W), with an increase of 30% and 29% for DH605 and ZD958, respectively. Waterlogging significantly decreased antioxidative enzyme activities, accelerating leaf senescence, resulted in the disorder of leaf gas exchange parameters and chlorophyll fluorescence parameters. In addition, waterlogging decreased key enzyme activities of carbon metabolism (ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase), with the most significant reduction in V3‐W, with a decrease of 46% and 49% for DH605, and 53% and 55% for ZD958, respectively. Visibly, waterlogging disturbed carbon metabolism, affected plant endogenous hormone content, accelerated leaf senescence and eventually resulted in a significant reduction in photosynthetic characteristic and grain yield. V3 was most susceptible to waterlogging, followed by V6 and 10VT.  相似文献   
47.
Peas (Pisum sativum L.) are exposed to waterlogging at germination when grown as relay in rice‐based cropping. Ninety‐one germplasm accessions were evaluated in relay (sown in waterlogged soil), and subsequently 10 diverse genotypes compared under relay and sole cropping (conventional tillage sowing) over two seasons in Bangladesh. Contrasting genotypes, BM‐3, NL‐2 and Kaspa, were further evaluated in three waterlogging treatments (drained control, 4 and 8 days waterlogging) in the glasshouse. Conspicuous variation in waterlogging tolerance at germination was observed in the field and confirmed under controlled conditions. In relay sowing in 2011, emergence of a few genotypes was affected by waterlogging. In 2012, emergence in relay was severely affected (12 plants/m2) compared to sole sowing (37 plants/m2). Among genotypes BM‐3 had 6 plants/m2 emerge, which all subsequently died, in contrast to NL‐2 in which emergence was 13 plants/m2 with all plants surviving. In the glasshouse, there was 14% emergence in BM‐3, 40% in NL‐2 and 55% in Kaspa after 8 days of waterlogging. Such marked differences in waterlogging tolerance at germination in the model pea are the first reported and illustrate prospects for selection to improve adaptation to relay sowing in South Asia.  相似文献   
48.
【背景】苹果(Malus×domestica Borkh)是我国主要栽培果树树种之一,但部分苹果产区由于夏、秋季的大量集中降雨和排水不良等造成果园涝害频繁发生,导致苹果树叶片黄化、脱落,果实品质和产量下降。【目的】鉴定苹果耐涝相关基因,为苹果耐涝分子标记辅助育种和优质高产栽培提供依据。【方法】以耐涝苹果砧木G41和不耐涝苹果砧木新疆野苹果(M. sieverii (Ledeb) Roem.)及其构建的包含495个F1杂交后代为材料,从F1杂交群体中挑选出耐涝和不耐涝株系各50株,构建两个极端性状DNA混池,采用简化基因组测序(SLAF-seq)技术,开发SLAF标签和SNP标记,结合苹果基因组信息和遗传关联性分析,对苹果耐涝基因进行定位及候选基因预测,并对候选基因在耐涝差异的株系中进行淹水胁迫下的表达分析。【结果】以‘金冠’苹果为参考基因组,共开发119 072个SLAF标签,其中多态性SLAF有11 133个。通过序列分析和检测SNP位点,共获得6 237 071个SNP,其中高质量SNP有170 617个。通过ED和SNP-index方法关联分析,获得一个与耐涝性状紧密关联的候选区域,位于苹果第10号染色体1.94—3.25 Mb,关联区域大小为1.31 Mb,关联区域内包含120个基因。对该区域内基因进行功能注释,发现一个与呼吸代谢相关的基因—乙醇脱氢酶基因ADH1(MD10G1014500),在淹水处理后1、2、4和6 d,该基因在耐涝植株中的表达量显著高于不耐涝植株。【结论】将苹果耐涝基因定位于第10号染色体1.94—3.25 Mb处,筛选到可能与苹果耐涝相关的候选基因MD10G1014500,可用于苹果耐涝基因的克隆和功能解析。  相似文献   
49.
6‐Benzyladenine (6‐BA, a synthetic cytokinin) could improve the ability to resist adversity. However, very little attention has been given to its role in alleviating waterlogging damages on grain growth. A field experiment was performed to investigate effects of exogenous 6‐BA after waterlogging for 6 days at the third leaf stage (V3‐WL + 6‐BA) or the sixth leaf stage (V6‐WL + 6‐BA) on grain filling, and endogenous hormone of summer maize hybrids DengHai605 (DH605) and ZhengDan958 (ZD958), which were planted popularly in China. Exogenous 6‐BA alleviated waterlogging damages on grain filling by improving grain weight and volume, which was beneficial to yield increase. Grain yield of DH605 under V3‐WL + 6‐BA and V6‐WL + 6‐BA increased by 16% and 12%, respectively, compared with that of V3‐WL (waterlogging at the third leaf stage) and V6‐WL (waterlogging at the sixth leaf stage), while the corresponding values for ZD958 increased by 20% and 15%, respectively. Moreover, exogenous 6‐BA alleviated waterlogging damages on grain endogenous hormone content by increasing levels of endogenous indole‐3‐acetic acid, zeatin riboside, and gibberellic acid, and decreasing level of abscisic acid in grain of waterlogged summer maize during grain‐filling periods. Clearly, exogenous 6‐BA improved grain‐filling characteristics, and endogenous hormone, resulting in a significant yield increase of waterlogged summer maize.  相似文献   
50.
The study describes the capacity of trees to control the rise in water table and thus prevent the formation of waterlogged soils and development of secondary salinization in canal irrigated areas. It was conducted in RCC lysimeters of 1.2 m dia. and 2.5 m depth filled with sandy loam alluvial soil (Typic Ustochrept), with provisions to maintain water table depth at 1, 1.5 and 2 m from the surface and groundwater salinity at 0.4, 3, 6, 9 and 12 dS m-1. The amount of water biodrained by eucalyptus (Eucalyptus tereticornis) and bamboo (Bambusa arundinacea) at the given water table depths and groundwater salinity levels was monitored over four years by daily measuring the water needed for maintaining the water table. The trees continued to absorb and transpire water throughout the year, the capacity being more in summer and rainy than that was in the winter season. The eucalyptus plant could biodrain 2880, 5499, 5518 and 5148 mm of water in the first, second, third and fourth year of study period, from non-saline groundwater and a water table depth of 1.5 m. The amount of water biodrained was more at 1.5 m as compared to 1 and 2 m water table depths. The biodrainage capacity of trees was significantly affected by the salinity of the groundwater. However, even at salinity of 12 dS m-1, the eucalyptus plant biodrained 53% of that under non-saline conditions. It was calculated that biodrainage could control water table rises upto 1.95, 3.48, 3.76 and 3.64 m in first, second, third and fourth year, respectively. The secondary salinity developed in the root zone, upto 45 cm depth, did not exceed 4 dS m-1 even at water table depth of 1 m with salinity of 12 dS m-1. The volume of water biodrained by bamboo increased with time and could control water table rises upto 1.09, 1.86, 2.46 and 2.96 m in first, second, third and fourth year of growth, respectively.This study indicates that due to high transpiration capacity and an ability to extract water from deeper layers containing saline groundwater, the trees can control the rise in water table in irrigation command areas and prevent the formation of waterlogged and eventually the saline wastelands.  相似文献   
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