共查询到20条相似文献，搜索用时 126 毫秒
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苹果树磷素营养诊断及施用技术答山西读者王林磷是果树三大营养要素之一，是核酸、酶、维生素及多种重要化会物的组成元素。磷可加强果树光合作用和碳水化合物的合成运转，促进氮素代谢，有利于细胞分裂、根系的伸长和地上部分的生长发育，提高果树抗旱、抗寒、抗病能力。... 相似文献
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全球气候变暖已成为当今世界重要的环境问题之一,对植物生长发育造成严重影响。马铃薯性喜冷凉,为浅根系作物,高温、干旱是马铃薯生长过程中面临的主要非生物胁迫,马铃薯生长发育与生理代谢直接受到其影响。笔者讨论了当前高温和干旱耐受性的鉴定方法,从马铃薯植株形态特征、细胞生理生化变化、分子水平响应等方面系统概述了马铃薯对高温和干旱胁迫的响应机制。从选育耐热抗旱新品种、应对高温干旱的栽培调控技术及基因工程等方面论述了提高马铃薯耐热抗旱的途径和措施,为马铃薯高温干旱研究提供理论参考,并对未来马铃薯耐高温和干旱研究方向和发展趋势进行了展望。 相似文献
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马铃薯是重要的粮菜饲料兼用作物,在我国主要分布在干旱和半干旱地区,干旱严重影响马铃薯的产量。因此,筛选抗旱资源、培育高产抗旱马铃薯品种至关重要。本试验首先对包含121个基因型的二倍体马铃薯群体进行抗旱性评价,依据抗旱系数将所有基因型分为5类。其中高抗旱材料16份,高旱敏感材料14份,进一步从各类别中分别选择1个基因型进行不同水分处理,测定株高、光合作用和叶绿素荧光相关指标及产量等,并计算各指标与产量和抗旱系数的相关性。结果表明:不同水分条件下,随着马铃薯的生长发育和干旱胁迫的加重,各指标与产量及抗旱系数的相关性会发生变化。因此,在筛选高产抗旱材料时,某些指标的测定需要在特定时期进行;盆栽条件下,基质相对含水量为35%～45%时,各基因型抗旱系数与大田的抗旱系数相关性最高,且在该水分处理下与抗旱系数显著相关的指标最多;现蕾期Height和Chl、盛花期PWUE和Tr与产量显著相关,可以用来初步判断各基因型产量的高低;盛花期基质相对含水量为75%～85%时,PWUE与抗旱系数显著正相关,可以用来区分所选基因型抗旱性的强弱。 相似文献
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植物内生菌次生代谢产物对干旱胁迫下辣椒幼苗生理机制的影响 总被引：1，自引：0，他引：1
以植物内生菌次生代谢产物为供试材料,以辣椒为研究对象,采用PEG-6000模拟干旱胁迫环境,研究了植物内生菌次生代谢产物对辣椒幼苗株高、叶长、茎粗、鲜重、干重、须根数等形态指标和叶片相对含水量、细胞膜相对透性、脯氨酸等生理指标的变化,探讨植物内生菌次生代谢产物对干旱胁迫下辣椒幼苗生理机制的影响。结果表明:辣椒幼苗经次生代谢产物处理后,试验组株高高于对照组30.91%,叶长高于对照组14.76%,茎粗高于对照组129.57%,须根数高于对照组33.33%,鲜重高于对照组33.37%,干重高于对照组43.79%,叶片相对含水量高于对照组8.71%,细胞膜透性低于对照组14.63%,脯氨酸含量高于对照组14.90%;该研究表明,植物内生菌次生代谢产物通过对辣椒幼苗形态和生理特性等方面的干旱适应性调节,来提高其抗旱能力。 相似文献
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探讨了以叶片水势((?)_L)、气孔阻力(Rs)、蒸腾速率(Tr)作为果树水分亏缺指标的可行性.结果表明:黎明前(?)_L与上午10时左右的净光合速率(Pn)Tr以及果实直径、土壤水分含量明显相关;晴朗天气下,上午10时左右的Rs、Tr对水分亏缺反应明显,与(?)_L、Pn、果实直径增长、土壤含水量明显相关.三个指标较好地反映出与树体水分亏缺相联系的生理过程及土壤含水量,可作为评估树体水分状况适宜程度的良好指标.研究也证明:相同条件下,树体各部分三指标的大小不同,根据灌溉应满足树体水分竞争代谢“弱者”的原则,(?)L的取样部位应为树冠上部枝条的下位叶,而Rs、Tr则为内膛无果短梢叶. 相似文献
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Citrus variegated chlorosis (CVC) is a disease caused by the bacterium Xylella fastidiosa. The most productive areas for citrus in Brazil are the northwestern and the northern regions of the São Paulo state, where CVC incidence is more severe. Additionally, these areas have the highest temperatures as well as significant vapor pressure deficits (VPD) and seasonal droughts. Environmental stresses are known to affect CVC-infected plants under semi-controlled conditions, but it is unclear whether similar effects occur in the field. The objective of this work was to evaluate the CVC leaf symptoms and environmental influences on fruit yield and size, and physiological parameters of healthy and CVC-affected plants (including both non-symptomatic and symptomatic leaves) in the morning and afternoon during the wet and dry seasons of 2003 in the southern, central and northern regions of the São Paulo state, Brazil. Increased VPD caused the stomatal conductance (gs) and CO2 assimilation rates (A) to drop in healthy plants, but diseased plants had low VPD influences on gs, especially closer to the northern region and in leaves that were more symptomatic, confirming that diseased plants do not respond to changes in environmental VPD, corroborating several results reported in the literature. Although symptomatic northern leaves exhibited low stomatal apertures, the northern region had the highest air temperatures and VPDs, increasing the water loss in these plants, suggesting that towards the northern region plants face greater atmospheric and soil water stress. The fruit size of diseased plants diminished towards the north, while the fruit size of healthy plants must have been influenced by the tree fruit load. We suggest that CVC-affected plants suffer greater physiological damage if grown under environmental constraint, such as that found in the northern region of the São Paulo state. 相似文献
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The frequency and intensity of heat stress events globally have increased over the past 20 years. Climatic modeling predicts that this trend will continue throughout the 21st century, with the global land area experiencing heat waves doubling by 2020 and quadrupling by 2040. Due to the reflective nature of buildings and infrastructure, heat temperatures tend to be higher within urban landscapes than outlying rural areas. Heat stress influences processes from the molecular level to whole-tree biology. At the leaf level, photosynthesis is reduced, photo-oxidative stress increases, premature leaf abscission occurs, and the growth of leaves decreases. Growth decreases at the whole tree level, and biomass allocation between roots, shoots, leaves, and branches is altered. When drought and heat stress are combined, detrimental effects are considerably enhanced and, without irrigation, can quickly lead to tree death. There have been few studies regarding the heat tolerance of urban tree species. However, there is evidence of genetic variation in heat tolerance between and within species within forestry, which could be essential to exploit for urban trees. Understanding the mechanisms of tree physiological, biochemical, and molecular responses to extreme heat events is also necessary for understanding how urban tree species will be affected by climate change. 相似文献
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干旱胁迫下桃树各部位贮存水调节能力的研究 总被引：2，自引：1，他引：2
干旱胁迫使桃品种瑞光5号(Prunuspersicavar.nectarinacv.RuiguangNo.5)的叶片水势和茎流下降,并且干旱越严重下降越多。干旱胁迫对贮存水调节量的影响不显著,但是绝对调节能力随干旱胁迫程度的增加而增加。各部位间的相对调节能力主要是由其水容、贮存水阻力和体积决定的,干旱胁迫对各部位间的相对调节能力的影响不显著。在充分灌水条件下各部位贮存水夜间的相对调节能力为:主根18.8%、主干38.5%、枝条17.8%、叶片3.4%、细根2.9%、果实6.7%、粗根12.0%,处理之间绝对调节能力的差异不显著。贮存水的调节主要来自主干、主根、粗根和枝条,这4部分占全部调节量的80%以上。 相似文献
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甜瓜幼苗耐湿性鉴定指标的研究 总被引：1，自引：0，他引：1
对水分胁迫下甜瓜幼苗叶片部分生理生化指标的研究结果表明,在淹水处理3天后,甜瓜幼苗的萎蔫指数、基部不定根数、电导百分率及MDA的含量在不同品种间存在明显差异,每两种指标间的相关性均达极显著水平。4种指标除不定根数与品种的耐湿性极显著正相关外,其余3种指标均与品种的耐湿性呈负相关。4种指标均可鉴定出甜瓜品种的耐湿性强弱。 相似文献
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以小果形辣椒Criollo de Morelos 334(CM334)和大果形辣椒Early Calwonder(EC)为试材,研究了在不浇水干旱胁迫开始时和胁迫期间喷施外源亚精胺(Spd)对辣椒幼苗叶片耐旱相关生理指标的影响。结果表明:干旱胁迫条件下,辣椒叶片萎蔫指数(WI)、丙二醛(MDA)含量、相对电导率(REC)升高,而外源喷施Spd可以缓解这些生理指标的升高,且在胁迫初期喷施亚精胺会使缓解作用更加明显。EC幼苗叶片中这些生理指标均低于CM334,说明前者的耐旱性高于后者。干旱胁迫和外源喷施Spd均未对辣椒叶片的叶绿素含量产生影响。 相似文献