Expansin的研究进展

随着对植物生长机制的不断深入研究,发现expansin蛋白具明显而广泛的促进生长的作用。简述了expansin蛋白的生化特性及其对细胞壁的松弛机制,同时介绍了expansin在水稻中的组织定位。     

Expansin的研究进展

随着对植物生长机制的不断深入研究,发现expansin蛋白具明显而广泛的促进生长的作用。简述了expansin蛋白的生化特性及其对细胞壁的松弛机制,同时介绍了expansin在水稻中的组织定位。     

Dynamics of leaf and root growth: endogenous control versus environmental impact

AIMS: Production of biomass and yield in natural and agronomic conditions depend on the endogenous growth capacity of plants and on the environmental conditions constraining it. Sink growth drives the competition for carbon, nutrients and water within the plant, and determines the structure of leaves and roots that supply resources to the plant later on. For their outstanding importance, analyses of internal growth mechanisms and of environmental impact on plant growth are long-standing topics in plant sciences. SCOPE: Recent technological developments have made it feasible to study the dynamics of plant growth in temporal and spatial scales that are relevant to link macroscopic growth with molecular control. These developments provided first insights into the truly dynamic interaction between environment and endogenous control of plant growth. CONCLUSIONS: Evidence is presented in this paper that the relative importance of endogenous control versus the impact of the dynamics of the environment depends on the frequency pattern of the environmental conditions to which the tissue is exposed. It can further be speculated that this is not only relevant within individual plants (hence leaves versus roots), but also crucial for the adaptation of plant species to the various dynamics of their environments. The following are discussed: mechanisms linking growth and concentrations of primary metabolites, and differences and homologies between spatial and temporal patterns of root and leaf growth with metabolite patterns.     

Effects of nitrogen addition on plant biomass and tissue elemental content in different degradation stages of temperate steppe in northern China

Aims Grassland degradation has become a common problem worldwide. Several studies have analyzed the effects of nitrogen (N) addition on plant growth in grasslands, but few have considered its effects on plant growth in degraded grasslands. The aim of this study was to evaluate the effects of N addition on plant growth in grasslands with different levels of degradation in Inner Mongolia, China.     

Analysing the role of soil properties, initial biomass and ozone on observed plant growth variability in a lysimeter study

This simulation study is based on a lysimeter experiment with juvenile beech trees (Fagus sylvatica L.) which were grown under ambient or doubled ambient atmospheric ozone concentrations. The aim of the study was to analyze the role of differences in soil properties, differences in initial biomass and ozone impacts on observed plant growth variability at the eight lysimeters of this experiment. For this purpose, we established a new simulation model based on the model system Expert-N by coupling soil water and nitrogen transport models with the plant growth model PLATHO, which was already tested and applied for juvenile beech. In order to parameterize the soil model, for all lysimeters soil hydraulic parameters as well as carbon and nitrogen stocks were measured. Simulation results reveal that the observed decreased growth rates under elevated ozone are due to ozone impacts on plant growth, whereas the high plant growth variability between lysimeters is to a major part the consequence of differences in soil hydraulic properties. Differences in initial biomass are of minor importance to explain plant growth variability in this experiment.     

Inference of allelopathy is complicated by effects of activated carbon on plant growth

Allelopathy can play an important role in structuring plant communities, but allelopathic effects are often difficult to detect because many methods used to test for allelopathy can be confounded by experimental artifacts. The use of activated carbon, a technique for neutralizing allelopathic compounds, is now employed in tests for allelopathy; however, this technique also could produce large experimental artifacts. In three independent experiments, it was shown that adding activated carbon to potting media affected nutrient availability and plant growth. For most species tested, activated carbon increased plant biomass, even in the absence of the potentially allelopathic agent. The increased growth corresponded to increased plant nitrogen content, likely resulting from greater nitrogen availability. Activated carbon also affected nitrogen and other nutrient concentrations in soil media in the absence of plants. The observed effects of activated carbon on plant growth can confound its use to test for allelopathy. The detection of allelopathy relies on the difference between plant growth in medium with carbon and that in medium without carbon in the presence of the potentially allelopathic competitor; however, this difference may be biased if activated carbon alters soil nutrient availability and plant growth even in the absence of the focal allelopathic agent.     

N-酰基高丝氨酸内酯调控植物生长发育的研究进展

植物与细菌之间存在着复杂的相互作用关系。N-酰基高丝氨酸内酯（AHLs）是革兰氏阴性细菌进行胞间通讯的信号分子,也是介导植物与细菌互作的重要信号分子,在调控植物生长发育方面起着重要作用。本文对近年来的相关研究进展作一综述,这将有助于全面了解植物与细菌间的信息交流机制,并对实际农业生产具有指导意义。     

Effect of simulated herbivory on growth of the invasive weed Hygrophila polysperma: Experimental and predictive approaches

Herbivory simulation studies, through mechanical removal of leaf tissue, provide valuable insight about plant compensation and tolerance to defoliation. A mesocosm experiment was conducted to examine the effects of defoliation on growth and biomass accumulation of Hygrophila polysperma and thereby determine the critical level of herbivory necessary to achieve significant reduction in growth of this invasive plant. The data collected during the experiment were used to develop an empirical plant growth model to examine the usefulness of a model-based approach for a priori understanding of plant response to defoliation. The results of the mesocosm experiment showed that defoliation significantly influenced growth and biomass accumulation of hygrophila. The empirical plant growth model accurately simulated plant growth response to herbivory across treatments. Based on the results of the mesocosm experiment, an insect defoliator that causes complete defoliation of hygrophila at least at monthly intervals may be able to reduce biomass and growth of hygrophila. The ability of the mathematical model to predict the effects of defoliation on hygrophila suggest that it could be a useful tool for the selection of effective biological control agents.     

植物离体培养中器官发生调控机制的研究进展

本文就离体培养的植物组织对生长调节物质的吸收和代谢,外源生长调节物质对内源激素水平的影响,内源激素对细胞脱分化和再分化的调控,生长素和细胞分裂素基因与器官发生的关系,与器官发生有关的基因和特异蛋白等问题的研究进展进行了评述,并对下一步研究提出了自己的看法。     

Community‐level plant–soil feedbacks explain landscape distribution of native and non‐native plants

Plant–soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short‐term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non‐native species, or a mixed plant community in different plots in a common‐garden experiment. After 4 years, plants were removed and one native and one non‐native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non‐native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non‐native, Centaurea diffusa, and non‐native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata. Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common‐garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non‐native plant community on non‐native soils. In contrast, when PSF effects were removed, the model predicted that non‐native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank‐order abundance of native and non‐native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors through soil‐mediated effects.     

植物生长调节物质的研究进展

述评了近几年国内外在植物激素与植物体内信使的传递、植物激素与基因诱导和表达、植物生长物质的复合使用、新型植物生长物质的开发及植物激素对提高植物抗逆性的作用等方面的研究进展,并展望了植物生长物质的发展趋势。     

Mechanism of plant growth promotion by rhizobacteria

Plant growth results from interaction of roots and shoots with the environment. The environment for roots is the soil or planting medium which provide structural support as well as water and nutrients to the plant. Roots also support the growth and functions of a complex of microorganisms that can have a profound effect on the growth anti survival of plants. These microorganisms constitute rhizosphere microflora and can be categorized as deleterious, beneficial, or neutral with respect to root/plant health. Beneficial interactions between roots and microbes do occur in rhizosphere and can be enhanced. Increased plant growth and crop yield can be obtained upon inoculating seeds or roots with certain specific root-colonizing bacteria- 'plant growth promoting rhizobacteria'. In this review, we discuss the mechanisms by which plant growth promoting rhizobacteria may stimulate plant growth.     

The role of mycorrhizae and plant growth promoting rhizobacteria (PGPR) in improving crop productivity under stressful environments

Both biotic and abiotic stresses are major constrains to agricultural production. Under stress conditions, plant growth is affected by a number of factors such as hormonal and nutritional imbalance, ion toxicity, physiological disorders, susceptibility to diseases, etc. Plant growth under stress conditions may be enhanced by the application of microbial inoculation including plant growth promoting rhizobacteria (PGPR) and mycorrhizal fungi. These microbes can promote plant growth by regulating nutritional and hormonal balance, producing plant growth regulators, solubilizing nutrients and inducing resistance against plant pathogens. In addition to their interactions with plants, these microbes also show synergistic as well as antagonistic interactions with other microbes in the soil environment. These interactions may be vital for sustainable agriculture because they mainly depend on biological processes rather than on agrochemicals to maintain plant growth and development as well as proper soil health under stress conditions. A number of research articles can be deciphered from the literature, which shows the role of rhizobacteria and mycorrhizae alone and/or in combination in enhancing plant growth under stress conditions. However, in contrast, a few review papers are available which discuss the synergistic interactions between rhizobacteria and mycorrhizae for enhancing plant growth under normal (non-stress) or stressful environments. Biological interactions between PGPR and mycorrhizal fungi are believed to cause a cumulative effect on all rhizosphere components, and these interactions are also affected by environmental factors such as soil type, nutrition, moisture and temperature. The present review comprehensively discusses recent developments on the effectiveness of PGPR and mycorrhizal fungi for enhancing plant growth under stressful environments. The key mechanisms involved in plant stress tolerance and the effectiveness of microbial inoculation for enhancing plant growth under stress conditions have been discussed at length in this review. Growth promotion by single and dual inoculation of PGPR and mycorrhizal fungi under stress conditions have also been discussed and reviewed comprehensively.     

植物激素ABA调控植物根系生长的研究进展

脱落酸（abscisic acid,ABA）是一种重要的植物激素,在调控种子发育、种子休眠与萌发、抑制生长、促进落花落果、参与植物应对外界环境胁迫等过程中发挥着重要的生理功能。ABA还能与其他植物激素（如生长素、乙烯等）互作进而精细调控植物根系的生长。本文以模式植物拟南芥（Arabidopsis thaliana（L.）Heynh）为主要对象,对近年来国内外在ABA调控植物根系生长方面的研究成果、ABA与其他植物激素（如GA等）互作调控根系生长及调控非生物逆境下根系发育的机理等进行综述,并对其未来的研究方向进行了展望。     

Promotion of Plant Growth by Bacterial ACC Deaminase

To date, there has been only limited commercial use of plant growth-promoting bacteria in agriculture, horticulture, and silviculture. However, with recent progress toward understanding the mechanisms that these organisms utilize to facilitate plant growth, the use of plant growth-promoting bacteria is expected to continue to increase worldwide. One of the key mechanisms employed by plant growth-promoting bacteria to facilitate plant growth is the lowering of plant ethylene levels by the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase. This article reviews the published work on this enzyme, with an emphasis on its biochemistry, protein structure, genes, and regulation. In addition, this article provides some initial insights into the changes in both plants and ACC deaminase-containing plant growth-promoting bacteria as a consequence of plant-microbe interactions. Finally, a brief discussion of how bacterial ACC deaminase and indoleacetic acid (IAA) together modulate plant growth and development is included.     

Fall in nutrient demand per unit root length during the linear phase of plant growth

If root length increases in proportion to plant weight, growth is expolinear, and plant composition is constant, then there is fundamental drop in nutrient demand per unit root length during the linear growth phase. This is in contrast to the exponential phase, when increments of growth and hence of nutrient demand are proportional to plant size and thus to root length: in the linear growth phase, they are constant despite increasing root length. For nutrient uptake models in which demand is based on growth and uptake is based on root length, this would suggest a tendency for nutrients to accumulate in the plant as it grows.     

模拟酸雨对蚕豆植物生长的影响

模拟酸雨对盆栽蚕豆(Vicai faba）植物生长的影响表明,它对出苗率影响不大,但当它的pH为2.0时则对蚕豆初期的出苗速率有一定的促进作用。在苗出土后,酸雨的作用由促进转变为抑制,并随酸雨pH值的降低而增大,致使株高、叶片生长和叶绿素含量减少,酸雨对叶片的伤害幼叶较老叶更容易。     

杀菌剂敌磺钠及植物生长调节剂对茭白孕茭的影响

以‘龙茭二号’为研究对象,通过在茭白植株不同生长发育阶段分别喷施杀菌剂敌磺钠和植物生长调节剂,比较分析其对茭白结茭的促进效果。对6个不同处理组合及对照材料的株高、内源激素含量变化及结茭情况的统计分析发现：喷施一定浓度的敌磺钠对茭白结茭具有明显的促进作用,以敌磺钠（标准浓度）＋营养液和敌磺钠（标准浓度）对茭白结茭产量的提高最为明显。植物生长调节剂处理能明显促进茭白早期植株生长,但对最终株高影响不大。采用间接酶联免疫法对茭白茎部3种激素（IAA、ABA和GA3）含量进行的比较分析表明：敌磺钠处理能够明显降低ABA含量,但对IAA和GA3含量没有明显影响;茭白结茭前ABA含量的降低可能有助于茭白结茭。     

Exploring the potentialities of beneficial endophytes for improved plant growth

Pathogen affects plant growth, host health and productivity. Endophytes, presumed to live inside the plant tissues, might be helpful in sustaining the future of agriculture. Although recent studies have proven that endophytes can be pathogenic, commensal, non-pathogenic, and/or beneficial, this review will focus on the beneficial category only. Beneficial endophytes produce a number of compounds which are useful for protecting plants from environmental conditions, enhancing plant growth and sustainability, while living conveniently inside the hosts. The population of endophytes is majorly controlled by location, and climatic conditions where the host plant grows. Often the most frequently isolated endophytes from the tissues of the plant are fungi, but sometimes greater numbers of bacteria are isolated. Beneficial endophytes stand a chance to replace the synthetic chemicals currently being used for plant growth promotion if carefully explored by researchers and embraced by policymakers. However, the roles of endophytes in plant growth improvement and their behavior in the host plant have not been fully understood. This review presents the current development of research into beneficial endophytes and their effect in improving plant growth.     

不同植物生长调节物质对细叶小羽藓愈伤组织诱导及分化的影晌

以细叶小羽藓[Haplocladium microphyllum（Hedw．）Broth．】的配子体为外植体,研究了不同植物生长调节物质对细叶小羽藓愈伤组织诱导及分化的影响。结果表明：在Ms培养基中添加不同的植物生长调节物质对细叶小羽藓配子体增殖影响差异很大,具体表现为2,4一D、KT、IBA和IAA促进细叶小羽藓芽体的诱导及生长,NAA抑制细叶小羽藓芽体的诱导,TDZ阿姨、、及6－BA促进细叶小羽藓的配子体产生愈伤组织;在Ms培养基中添加0．3mg·L－1。6-BA最适合愈伤组织的诱导;在MS掊养基中添加1．0mg·L－1。。IBA最适合愈伤组织的分化。