植物的光合作用与光合氮、碳代谢的耦联及调节

概述了光合作用反应与CO2同化和NO^-3/NO^-2还原的耦联关系,提出了应该从氮,碳代谢整合角度讨论作动和光合作用,以便根据生产目的,调节作物的氮,碳代谢,实现农业生产的高产,优质。     

利用合成生物学原理提高光合作用效率的研究进展

我国人口增多与耕地面积减少的矛盾日益突出,粮食安全已成为我国国民经济可持续发展的重要保障。光合作用是作物产量形成的物质基础,提高作物光能利用效率是提高作物产量的重要途径之一。本文从光合作用过程中光能高效吸收、传递与转化,光能高效利用和碳同化等三大模块综述了近期科学家利用合成生物学对光合作用改造的最新进展。最后我们对其在农业中的应用前景进行了展望,通过合成生物学原理提高光合作用效率可能将为增加粮食产量提供重要理论支撑和关键生物技术。     

从植物生理学谈光合作用与农业生产和粮食安全

目前,粮食安全问题已经成为了国家相关部门高度重视的一项问题,其不仅关系到社会经济的稳定发展,而且对人们生活生产也具有重要作用。我们都知道,当前我国所食用的食物都是光合作用的产物,因此,光合作用对农业生产和粮食安全的作用是不容忽视的。本文首先对植物生理学进行简要概述,并在此基础上对光合作用与农业生产和粮食安全进行介绍,以此来为今后我国粮食安全目标的实现提供一定的参考依据。     

浅谈光合作用在农业生产上的应用

从以下８个方面对植物的光合作用在农业生产上的应用进行了概述,利用间作套种;增施二氧化碳”气肥”;延长光合作用时间;培育高光效作物品种;选育有利于光合作用进行了株型;避免或减轻农作物“午休”期间的影响;合理应用生长调节物质;利用不同色光改善光合产物品质。     

光合作用在世纪之交的研究动向

当前光合作用的研究动向大致可分为３个方面：１）深入探讨光合作用反应机理,结构功能,特别是关于从水分子释放出氧气的过程和腺三磷的合成机理;２）了解光合机构的组装,运转与调节,包括叶绿体有关组分的生物合成与组装,光合作用各部分反应间的弹性衔接和协调,光合机构的运转与植物其它生命活动的配合及对环境变动的适应,在分子水平上进行生理研究等;３）研究与光合作用有关的生产实践上的重大问题,如农业生产和生态环境的     

光合作用研究进展：从分子机理到绿色革命

根据国际科学期刊Nature,Science和Photosynthesis Research等近年发表的60多篇文献评论了过去5年来光合作用研究领域的研究进展。这篇评论由光合机构的精细结构与光合作用的反应机理,光合作用的调节机制与环境胁迫和光合机理知识的应用与绿色革命三部分组成。第一部分包括天线和反应中心的结构,放氧机理和ATP合成的分子机理;第二部分涉及二磷酸核酮糖化酶／加氧酶,光抑制,氧化还原调节和光合作用的高温抑制。第三部分讨论新绿色革命的特点和艰巨性,指出新绿色革命的中心问题是作物光合效率的改善,锐利武器是基因工程,新绿色革命的成功有赖于对光合作用的深入理解和分子生物学家,植物物理学家,生物化学家与农学家们的协同努力。     

生物学高考专题辅导--植物的光合作用产量

植物的光合作用产量即植物在一段时间内积累有机物的总量 ,取决于光合作用和呼吸作用两方面。凡是影响光合作用和呼吸作用的因素都会影响植物的光合作用产量 ,这些因素包括光 (含光照强度、日照长度和光质 )、温度、大气中 CO2 含量、矿质元素等等。有关植物光合作用产量的考题在近几年的上海和广东生物学高考试卷中都占有相当的比例。这部分内容与农业、林业生产实际联系密切 ,既可以考查学生的基础知识 ,又可以考查学生运用所学知识分析和解决实际问题的综合能力。这部分考题以选择题、简答题和实验题等多种形式出现 ,而且常常结合图表 ,…     

光生态膜对黄瓜生态的影响

通过叶片的反射光谱测量来研究黄瓜的光合作用之作用光谱,采用在高分子树脂中分散进荧光助剂、着色剂来模拟栽培作物的作用光谱。用这种光生态膜苫盖日光温室进行黄瓜生产,产量提高了２１．４％。     

光调光合作用的信号转导机制

光调光合作用的信号转导机制陈以峰,周燮（南京农业大学农学系,江苏省农业科学院遗传生理研究所南京２１００１４南京２１００９５）１导言自然条件下光合作用受到多种光环境的影响和调节,例如瞬时光强变化、昼夜光暗变化、光强日变化、光强季节变化等等。在变动光环境...     

植物光合作用的多样性

植物光合作用的多样性文宗（四川省成都市第七中学,６１００１５）光合作用既是生物学中最古老的问题,也是当前生物学的前沿之一,因为它不仅在农业,能源,生态等问题中具有重大实际意义,而且在生命起源,进化与光能转换等生物学基本理论问题中也很重要。但自１７７１...     

The impact of modifying photosystem antenna size on canopy photosynthetic efficiency—Development of a new canopy photosynthesis model scaling from metabolism to canopy level processes

Canopy photosynthesis (A_c) describes photosynthesis of an entire crop field and the daily and seasonal integrals of A_c positively correlate with daily and seasonal biomass production. Much effort in crop breeding has focused on improving canopy architecture and hence light distribution inside the canopy. Here, we develop a new integrated canopy photosynthesis model including canopy architecture, a ray tracing algorithm, and C₃ photosynthetic metabolism to explore the option of manipulating leaf chlorophyll concentration ([Chl]) for greater A_c and nitrogen use efficiency (NUE). Model simulation results show that (a) efficiency of photosystem II increased when [Chl] was decreased by decreasing antenna size and (b) the light received by leaves at the bottom layers increased when [Chl] throughout the canopy was decreased. Furthermore, the modelling revealed a modest ~3% increase in A_c and an ~14% in NUE was accompanied when [Chl] reduced by 60%. However, if the leaf nitrogen conserved by this decrease in leaf [Chl] were to be optimally allocated to other components of photosynthesis, both A_c and NUE can be increased by over 30%. Optimizing [Chl] coupled with strategic reinvestment of conserved nitrogen is shown to have the potential to support substantial increases in A_c, biomass production, and crop yields.     

Natural genetic variation in photosynthesis: an untapped resource to increase crop yield potential?

Raising crop yield potential is a major goal to ensure food security for the growing global population. Photosynthesis is the primary determinant of crop productivity and any gain in photosynthetic CO₂ assimilation per unit of leaf area (A) has the potential to increase yield. Significant intraspecific variation in A is known to exist in various autotrophic organs that represent an unexploited target for crop improvement. However, the large number of factors that influence photosynthetic rates often makes it difficult to measure or estimate A under dynamic field conditions (i.e. fluctuating light intensities or temperatures). This complexity often results in photosynthetic capacity, rather than realized photosynthetic rates being used to assess natural variation in photosynthesis. Here we review the work on natural variation in A, the different factors determining A and their interaction in yield formation. A series of drawbacks and perspectives are presented for the most common analyses generally used to estimate A. The different yield components and their determination based on different photosynthetic organs are discussed with a major focus on potential exploitation of various traits for crop improvement. To conclude, an example of different possibilities to increase yield in wheat through enhancing A is illustrated.     

FACE-ing the global change: Opportunities for improvement in photosynthetic radiation use efficiency and crop yield

The earth is rapidly changing through processes such as rising [CO₂], [O₃], and increased food demand. By 2050 the projected atmospheric [CO₂] and ground level [O₃] will be 50% and 20% higher than today. To meet future agricultural demand, amplified by an increasing population and economic progress in developing countries, crop yields will have to increase by at least 50% by the middle of the century. FACE (Free Air Concentration Enrichment) experiments have been conducted for more than 20 years in various parts of world to estimate, under the most realistic agricultural conditions possible, the impact of the CO₂ levels projected for the middle of this century on crops. The stimulations of crop seed yields by the projected CO₂ levels across FACE studies are about 18% on average and up to 30% for the hybrid rice varieties and vary among crops, cultivars, nitrogen levels and soil moisture. The observed increase in crop yields under the projected CO₂ levels fall short of what would be required to meet the projected future food demand, even with the most responsive varieties. Crop biomass production and seed yield is the product of photosynthetic solar energy conversion. Improvement in photosynthetic radiation use efficiency stands as the most promising opportunity allowing for major increases in crop yield in a future that portends major changes in climate and crop growing environments. Our advanced understanding of the photosynthetic process along with rapidly advancing capabilities in functional genomics, genetic transformation and synthetic biology promises new opportunities for crop improvement by greater photosynthesis and crop yield. Traits and genes that show promise for improving photosynthesis are briefly reviewed, including enhancing leaf photosynthesis capacity and reducing photorespiration loss, manipulating plant hormones’ responses for better ideotypes, extending duration of photosynthesis, and increasing carbon partitioning to the sink to alleviate feedback inhibition of photosynthesis.     

What is the maximum efficiency with which photosynthesis can convert solar energy into biomass?

Photosynthesis is the source of our food and fiber. Increasing world population, economic development, and diminishing land resources forecast that a doubling of productivity is critical in meeting agricultural demand before the end of this century. A starting point for evaluating the global potential to meet this goal is establishing the maximum efficiency of photosynthetic solar energy conversion. The potential efficiency of each step of the photosynthetic process from light capture to carbohydrate synthesis is examined. This reveals the maximum conversion efficiency of solar energy to biomass is 4.6% for C3 photosynthesis at 30 degrees C and today's 380 ppm atmospheric [CO2], but 6% for C4 photosynthesis. This advantage over C3 will disappear as atmospheric [CO2] nears 700 ppm.     

不同时期毛乌素沙区主要植物种光合作用和蒸腾作用的变化

 采用LI—6000便携式光合分析系统对毛乌素沙区主要植物种油蒿、中间锦鸡儿、旱柳进行了不同时期光合作用,蒸腾作用日进程的测定,并同步测定有效光辐射、空气相对湿度、叶温、气温、胞间CO2浓度、气孔阻力、叶片水势及土壤水势等因子;结果表明：不同时期、不同植物种其光合、蒸腾特征各异;植物的光合、蒸腾与环境因子和植物内部因子之间有密切关系,其中有效光辐射是影响光合作用、蒸腾作用诸因子中的主导因子,而气孔阻力变化则在调节光合和蒸腾中起着重要作用;不同植物种间气孔对环境条件变化的响应程度不同,以中间锦鸡儿最为灵敏;3种植物的水分利用效率表明,中间锦鸡儿的水分利用效率较油蒿、旱柳为高。     

狗尾草蒸腾特性与水分利用效率对模拟光辐射增强和CO2浓度升高的响应

 在人工控制光照强度和CO2浓度条件下,测量了禾本科C4植物狗尾草（Setaria viridis）的光合速率（Pn）,蒸腾速率（Tr）,胞间CO2浓度（Ci）,气孔导度（Gs）和叶面饱和水汽压亏缺（Vpdl）对不同模拟光辐射（SPR）强度与CO2浓度的响应。结果表明：Pn, Tr 及Gs均随SPR的升高而增大,增幅趋缓,最终趋于动态平衡。SPR增强的起始阶段,水分利用率（WUE）逐渐增大,在SPR为1200 μmol·m-2·s-1时达到最大值,然后逐渐降低。Ci与Vpdl则随SPR的增强而减小,SPR高于600 μmol·m-2·s-1之后,两者均达到平衡状态。CO2浓度从300增至600 μmol·mol-1的过程中,狗尾草Pn逐渐增大,从600增至1 000 μmol·mol-1过程中,其Pn逐渐降低。Ci、Vpdl和WUE随CO2浓度的升高而增大,Gs和Tr则随CO2浓度的升高而减小。即禾本科一年生C4植物的光合作用对CO2浓度升高响应不敏感,水分蒸腾消耗的减少和WUE的提高对CO2浓度升高的响应极显著。可见,CO2浓度升高对C4植物光合作用的直接促进作用有限,但是却能从提高现有水分利用效率途径促进植物的第一性生产。     

Future research directions in plant signal transduction mechanisms

Photosynthesis is the ultimate driving force behind world food production. Modern agricultural practices have done much to maximize the benefits of photosynthesis through better land management and intensive crop breeding. However, enhancement in grain production is becoming increasingly dependent on biotechnology with every improvement becoming more difficult to achieve. With several crop species nearing the physical limits of grain production, more attention will be given to methods that enable farmers to consistently attain maximum yields. These efforts focus in part on how plants respond to the biotic and abiotic stresses that can significantly reduce potential yields, including the study of plant signal transduction pathways related to stress responses. Strong evidence is emerging that these pathways share many similarities to classical mammalian receptor systems including tyrosine-kinase receptors and G protein-coupled receptors. Several putative receptor-like proteins have been identified in maize and provide vast opportunities for studying plant signal transduction mechanisms. The elucidation of plant signaling pathways combined with modern technologies will not only serve to push harvest yields closer to the maximum theoretical levels but may also provide opportunities for actually increasing the theoretical maximum.     

Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields

Photosynthesis started to evolve some 3.5 billion years ago CO₂ is the substrate for photosynthesis and in the past 200–250 years, atmospheric levels have approximately doubled due to human industrial activities. However, this time span is not sufficient for adaptation mechanisms of photosynthesis to be evolutionarily manifested. Steep increases in human population, shortage of arable land and food, and climate change call for actions, now. Thanks to substantial research efforts and advances in the last century, basic knowledge of photosynthetic and primary metabolic processes can now be translated into strategies to optimize photosynthesis to its full potential in order to improve crop yields and food supply for the future. Many different approaches have been proposed in recent years, some of which have already proven successful in different crop species. Here, we summarize recent advances on modifications of the complex network of photosynthetic light reactions. These are the starting point of all biomass production and supply the energy equivalents necessary for downstream processes as well as the oxygen we breathe.