双酚A与镉对植物光合作用的复合微生态效应

近年来,国内外学者研究了双酚A (BPA)及重金属镉(Cd)单一因子对植物光合作用的影响.但在自然背景下,污染多呈复合型,因此研究BPA和Cd对二者叠加的空间内植物光合作用的复合影响意义重大.本文综述了BPA对植物光合作用的影响及机制,及Cd对植物光合作用的影响及其机制,其中单一BPA和Cd对植物光合作用的影响均表现为:低浓度促进光合作用,高浓度反之.根据相关研究推测了植物在受到复合胁迫时的生态响应,相应的生理生化反应,及光合过程的响应机制.最后提出了BPA与Cd对植物复合胁迫可能开展的相关研究方向.     

植物干旱胁迫响应机制研究进展——从表型到分子

干旱胁迫是抑制植物生长发育的主要限制因子之一,植物为适应干旱的外界环境,会依据自身的习性启动响应机制。从植物外部形态、生理代谢、生化过程、细胞及分子水平的变化阐述了植物对干旱胁迫的响应机制,详细阐述了生理及分子水平的响应机制,并对分子和遗传水平的响应机制和植物抗旱性关系的未来研究方向提出了展望,以期为植物抗逆性及遗传育种研究提供参考。     

植物响应联合胁迫机制的研究进展

自然界中, 植物通常面对多重联合胁迫。在全球气候变化日益加剧的背景下, 多重联合胁迫对植物生长发育及作物产量形成的不利影响日益显著。阐明植物响应和适应联合胁迫的生理与分子机制, 对人们理解植物对自然环境的适应机理, 及培育耐受联合胁迫的新品种有重要意义。研究表明, 植物响应联合胁迫的机制是特异的, 不能简单地从单一胁迫响应叠加来推断。植物遭受联合胁迫时, 各种生理、代谢和信号途径相互作用, 使得植物响应联合胁迫非常复杂。该文综述了植物响应联合胁迫的生理与分子机理的最新进展, 并阐述了植物响应联合胁迫的研究方法。     

植物响应联合胁迫机制的研究进展

自然界中, 植物通常面对多重联合胁迫。在全球气候变化日益加剧的背景下, 多重联合胁迫对植物生长发育及作物产量形成的不利影响日益显著。阐明植物响应和适应联合胁迫的生理与分子机制, 对人们理解植物对自然环境的适应机理, 及培育耐受联合胁迫的新品种有重要意义。研究表明, 植物响应联合胁迫的机制是特异的, 不能简单地从单一胁迫响应叠加来推断。植物遭受联合胁迫时, 各种生理、代谢和信号途径相互作用, 使得植物响应联合胁迫非常复杂。该文综述了植物响应联合胁迫的生理与分子机理的最新进展, 并阐述了植物响应联合胁迫的研究方法。     

植物淹水胁迫的生理学机制研究进展

淹水胁迫引起弱光环境,使气体扩散受限,叶片细胞膜脂过氧化加剧,体内保护酶系统受损,叶绿素降解,丙二醛含量积累,光合速率下降。为了适应淹水环境,植物通过生理生化机制的调节来保证淹水条件下的生命活动。如细胞通过调节渗透物质的含量来保持渗透势的平衡;细胞内各种抗氧化酶活性增加,以清除自由基,避免或者减轻细胞受到伤害;改变代谢途径和激素调节以保持能量储备和低的代谢速率。本文综述了淹水胁迫对细胞膜系统及功能、植物光合作用、植物呼吸、激素、生理代谢、基因调控的影响和淹水结束后植物的生理生态学变化,介绍了植物适应淹水胁迫的机制,并指出植物耐淹响应的分子机理,环境因素对淹没植物的影响,森林淹水胁迫的定位观测是今后需要研究的方面。     

WRKY对糖调控园艺作物冷适应的研究进展

植物的糖既能参与细胞的碳和能量代谢,又能作为信号分子促进植株生长发育并参与调控植物对逆境胁迫的响应.目前诸多研究表明抗寒锻炼中可溶性糖的积累有助于保护植物抵御冻害,黄瓜等园艺作物的抗冷性在外源施糖后提高,但具体机制尚未明确.糖能够促进植株通过表观形态、生理生化及分子水平等方面对非生物逆境胁迫响应、调控植株的抗性.糖代谢...     

植物在重金属胁迫下响应机制的研究进展

随着重金属污染越来越严重,植物各种生理生化指标随之发生改变,但其机理研究甚少。研究不同重金属对植物的影响以及在植物中的遗传及表观遗传机制,对于人们认识植物对重金属的耐性以及重金属污染区的植物修复都有重要意义。本文总结了各种植物应对不同重金属时生理变化、酶代谢与表观遗传机制的变化,为植物在重金属胁迫下的响应机制研究提供了新的思路。     

碱蓬属植物耐盐机理研究进展

碱蓬属(Suaeda)植物是一类典型的真盐生植物,属于重要的盐生植物资源,全球广泛分布.人们已经对20种碱蓬属植物进行了观察和盐胁迫实验,研究了不同器官或组织的生理生化特征及其对盐胁迫的反应,并基于这些研究分析了盐胁迫的应答机制.叶片肉质化、细胞内离子区域化、渗透调节物质增加和抗氧化系统能力增强是碱蓬属植物响应和适应盐胁迫的重要方式和途径.但迄今为止的研究工作尚有一定的局限性,主要包括:研究工作主要集中在植物地上部分,而对植物地下部分的研究较少;多是少数生物学指标或生理学现象的单独观察,而缺乏对生理代谢过程的整体和综合分析;针对某种碱蓬的独立分析较多,而与近缘种的比较研究较少;植物对中性盐胁迫的反应研究较多,而对碱性盐的研究较少.为进一步系统阐明碱蓬属植物的耐盐机制,今后的工作应注重碱蓬属植物响应和适应盐胁迫的信号网络和调控机制研究,基于系统生物学研究思路,采用现代组学技术探索该属植物响应盐胁迫的由复杂信号网络调控的特殊生理特征和特异代谢途径.     

植物响应低温胁迫的应答机制

介绍了植物响应低温胁迫的生理生化和分子机制及其信号转导途径的研究进展。并对今后这一领域研究前景作了展望和讨论。     

植物应答低温胁迫机制的研究进展

低温是植物生长过程中遇到的主要环境胁迫因子之一,而植物响应低温胁迫是一个多因素协同作用的过程,涉及到复杂的基因表达调控网络。尤其是低温下植物体内生理生化、细胞骨架结构及基因表达调控等方面的改变及相关机制,一直受到研究者的普遍关注。该文主要从细胞学及分子生物学等角度入手,将低温胁迫下植物对低温的响应及可能机制进行综述,着重对植物通过细胞内部细胞器结构与功能的改变来抵御或适应低温,尤其对细胞骨架,以及低温信号转导受体及中间体、下游胁迫相关基因的表达及其在细胞内部的调控及应答机制等方面的作用进行探讨,为耐低温植物新品种的培育及农业生产实践提供理论指导。     

Physiological and biochemical analysis of mechanisms underlying cadmium tolerance and accumulation in turnip

The capacity of plants to accumulate cadmium (Cd) is significant for phytoremediation of Cd-polluted soils. Turnips cultivated in China include species featuring high Cd accumulation and some of these plants act as Cd hyperaccumulator landraces. These plants can accumulate over 100 mg Cd kg^-1 dry weight in leaves without injury. Hence, studies that explore mechanisms underlying Cd detoxification and transport in turnip plants are essential. In the present study, we compared physiological and biochemical changes in turnip leaves treated with two Cd concentrations to controls. We discovered that Cd stress significantly increased the enzymatic activities or compound contents in the antioxidant system, including members of the glutathione-ascorbic acid cycle, whereas oxidation of reactive oxygen species (ROS) remained stable. Cd treatments also increased the contents of phytochelatins as well as a number of amino acids. Based on these results, we conclude that turnips initiate a series of response processes to manage Cd treatment. First, the antioxidant system maintaining ROS homeostasis and osmotic adjustment is excited to maintain stability of cell osmotic potential. Cd is chelated into its stable form to reduce its toxicity. Cd is possibly transported to vacuoles or non-protoplasts for isolation. Amino acid synthesis may directly and indirectly play an important role in these processes. This study partly revealed physiological and biochemical mechanisms underlying turnip response to Cd stress and provides information on artificially increasing or decreasing Cd accumulation in turnips and other plants.     

Effects of nitrogen on the activity of antioxidant enzymes and gene expression in leaves of Populus plants subjected to cadmium stress

The research aimed to verify the important physiological effect of nitrogen (N) on plants exposed to cadmium (Cd). The poplar plants were grown in a Hoagland nutrient solution and treated with extra N, Cd, and N + Cd. After treatment, plant growth and chlorophyll content were recorded. The oxidative stress, the activity of antioxidant enzymes, and the expression of related genes were also examined. The results indicated the plants treated with sole Cd presented obvious toxicity symptoms, i.e. growth inhibition, reactive oxygen species accumulation, and chlorophyll content decrement. However, when N was added to the plants under Cd stress, plant growth was enhanced, chlorophyll synthesis was promoted, and the oxidative stress was alleviated. Further, the expression of antioxidant enzymes genes was upregulated by N. The results indicated that N partially reversed the toxic effect of Cd on poplar plants, which can provide new methodology to enhance the phytoremediation technology for heavy metal pollution soil.     

镉毒害下植物氧化胁迫发生及其信号调控机制的研究进展

土壤重金属污染引发了一系列严峻的环境问题.其中,镉(Cd)是生物毒性最强的重金属元素之一.活性氧(ROS)过量积累引起的氧化胁迫,是Cd毒害植物的主要原因之一.本文围绕Cd胁迫引起的ROS积累及清除过程,重点阐述介导上述过程的一些信号调控物质包括一氧化氮(NO)、钙(Ca)、植物激素如生长素(IAA)和脱落酸(ABA)等及有丝分裂原活化蛋白激酶(MAPKs)的变化及其在缓解Cd诱导的氧化胁迫中的作用,以期为今后植物抗Cd胁迫生理生化机制的研究提供一定的理论依据.     

Role of salicylic acid in resistance to cadmium stress in plants

Key message

We review and introduce the importance of salicylic acid in plants under cadmium stress, and provide insights into potential regulatory mechanisms for alleviating cadmium toxicity.

Abstract

Cadmium (Cd) is a widespread and potentially toxic environmental pollutant, originating mainly from rapid industrial processes, the application of fertilizers, manures and sewage sludge, and urban activities. It is easily taken up by plants, resulting in obvious toxicity symptoms, including growth retardation, leaf chlorosis, leaf and root necrosis, altered structures and ultrastructures, inhibition of photosynthesis, and cell death. Therefore, alleviating Cd toxicity in plants is a major aim of plant research. Salicylic acid (SA) is a ubiquitous plant phenolic compound that has been used in many plant species to alleviate Cd toxicity by regulating plant growth, reducing Cd uptake and distribution in plants, protecting membrane integrity and stability, scavenging reactive oxygen species and enhancing antioxidant defense system, improving photosynthetic capacity. Furthermore, SA functions as a signaling molecule involved in the expression of several important genes. Significant amounts of research have focused on understanding SA functions and signaling in plants under Cd stress, but several questions still remain unanswered. In this article, the influence of SA on Cd-induced stress in plants and the potential regulation mechanism for alleviating Cd toxicity are reviewed.

     

Insights into the Role of Gasotransmitters Mediating Salt Stress Responses in Plants

Salinity stress is one of the most significant global issues that negatively affect plant growth and development. Modern agricultural practices have expanded the destructive effects of salinity stress, affecting plants through immediate osmotic stress, followed by a slow onset of ionic or hyper-osmotic stress. Plants alteration and resistance to salinity stress involve complex physiological, biochemical, and molecular systems to maintain homeostasis. As of late, the investigation of gaseous molecules in plants has attained much consideration, particularly for abiotic stress. Abiotic stresses generally initiate gasotransmitter (GT) generation in plants. In the interim, these GTs enhance the accumulation and activities of few antioxidant molecules, check the destructiveness of reactive oxygen species (ROS), and improve plant resilience under different stress conditions. The current review presented the role of gaseous molecules in plants under salinity stress, which include nitric oxide (·NO), hydrogen sulfide (H₂S), hydrogen gas (H₂), carbon monoxide (CO), methane (CH₄), and the only gaseous phytohormone ethylene. Further, we highlighted the underlying molecular mechanisms of the gasotransmitter signaling and cross-talks in salinity stress. Also, we presented a general update on the inclusion of GT in salt stress response, including the research gaps and its applications in the advancement of salinity-resistant plants.

     

Effects of Melatonin on Growth,Physiology and Gene Expression in Rice Seedlings Under Cadmium Stress

Melatonin (MLT) is a hormonal substance found in many organisms and can improve plant stress resistance. In this study, the japonica rice variety Y32 and indica rice variety NJ6 were cultivated in hydroponics under different concentrations of CdCl₂ at the two-leaf stage. The growth, physiological and biochemical responses of the seedlings and the expression of cadmium (Cd)-related genes under exogenous melatonin (MLT) treatment were assessed. The results indicated that Cd stress destroyed the dynamic balance between reactive oxygen species (ROS) production and removal, resulting in ROS accumulation, membrane lipid peroxidation, and impaired growth and development. Following the application of exogenous MLT to rice seedlings, increases in plant biomass including both underground and above-ground areas were observed. MLT also scavenged the inhibition of superoxide dismutase (SOD) and peroxidase (POD) in a concentration dependent manner in response to Cd stress. Catalase (CAT) activity and malondialdehyde (MDA) expression also decreased following MLT treatment. Amongst the six Cd-related genes assessed, five genes were down-regulated and one was up-regulated in response to MLT treatment. Taken together, these data demonstrate that MLT improves the resilience of rice seedlings at the biochemical, physiological, and molecular levels, and diminishes the damage caused by Cd stress.     

Morphogenic effects of abiotic stress: reorientation of growth in Arabidopsis thaliana seedlings

Abiotic stress responses include changes in physiological and biochemical processes as well as morphological and developmental patterns. It has remained an enigma which mechanisms are responsible for stress-induced morphogenesis. In this paper we demonstrate that stress induced phenotypes comprise a re-orientation rather than a cessation of growth. Moreover, strong similarities between the phenotypes induced by excess copper, paraquat, salicylic acid and a hydrogen peroxide analogue, indicate that a common molecular-physiological response system mediates these morphogenic stress responses. It is proposed that reactive oxygen species play a key role in controlling the architectural changes in stressed Arabidopsis thaliana seedlings.We found that phenotypes of plants exposed to stress resemble, in terms of the redistribution of growth, plants altered in phytohormone metabolism. We also found that plants in which polar auxin transport is blocked with TIBA, strongly resemble, but are not identical to, plants exposed to abiotic stress. Based on the stress induced formation of lateral roots, we surmise that stress induces local auxin accumulation near the root pericycle.     

Physiological adaptive mechanisms of plants grown in saline soil and implications for sustainable saline agriculture in coastal zone

There is large area of saline abandoned and low-yielding land distributed in coastal zone in the world. Soil salinity which inhibits plant growth and decreases crop yield is a serious and chronic problem for agricultural production. Improving plant salt tolerance is a feasible way to solve this problem. Plant physiological and biochemical responses under salinity stress become a hot issue at present, because it can provide insights into how plants may be modified to become more tolerant. It is generally known that the negative effects of soil salinity on plants are ascribed to ion toxicity, oxidative stress and osmotic stress, and great progress has been made in the study on molecular and physiological mechanisms of plant salinity tolerance in recent years. However, the present knowledge is not easily applied in the agronomy research under field environment. In this review, we simplified the physiological adaptive mechanisms in plants grown in saline soil and put forward a practical procedure for discerning physiological status and responses. In our opinion, this procedure consists of two steps. First, negative effects of salt stress are evaluated by the changes in biomass, crop yield and photosynthesis. Second, the underlying reasons are analyzed from osmotic regulation, antioxidant response and ion homeostasis. Photosynthesis is a good indicator of the harmful effects of saline soil on plants because of its close relation with crop yield and high sensitivity to environmental stress. Particularly, chlorophyll a fluorescence transient has been accepted as a reliable, sensitive and convenient tool in photosynthesis research in recent years, and it can facilitate and enrich photosynthetic research under field environment.     

Photosynthesis and antioxidative defense mechanisms in deciphering drought stress tolerance of crop plants

Crop plants are regularly exposed to an array of abiotic and biotic stresses, among them drought stress is a major environmental factor that shows adverse effects on plant growth and productivity. Because of this these factors are considered as hazardous for crop production. Drought stress elicits a plethora of responses in plants resulting in strict amendments in physiological, biochemical, and molecular processes. Photosynthesis is the most fundamental physiological process affected by drought due to a reduction in the CO₂ assimilation rate and disruption of primary photosynthetic reactions and pigments. Drought also expedites the generation of reactive oxygen species (ROS), triggering a cascade of antioxidative defense mechanisms, and affects many other metabolic processes as well as affecting gene expression. Details of the drought stress-induced changes, particularly in crop plants, are discussed in this review, with the major points: 1) leaf water potentials and water use efficiency in plants under drought stress; 2) increased production of ROS under drought leading to oxidative stress in plants and the role of ROS as signaling molecules; 3) molecular responses that lead to the enhanced expression of stress-inducible genes; 4) the decrease in photosynthesis leading to the decreased amount of assimilates, growth, and yield; 5) the antioxidant defense mechanisms comprising of enzymatic and non-enzymatic antioxidants and the other protective mechanisms; 6) progress made in identifying the drought stress tolerance mechanisms; 7) the production of transgenic crop plants with enhanced tolerance to drought stress.