Future directions in the ontogeny of plant defence: understanding the evolutionary causes and consequences

Plant defence often varies by orders of magnitude as plants develop from the seedling to juvenile to mature and senescent stages. Ontogenetic trajectories can involve switches among defence traits, leading to complex shifting phenotypes across plant lifetimes. While considerable research has characterised ontogenetic trajectories for now hundreds of plant species, we still lack a clear understanding of the molecular, ecological and evolutionary factors driving these patterns. In this study, we identify several non‐mutually exclusive factors that may have led to the evolution of ontogenetic trajectories in plant defence, including developmental constraints, resource allocation costs, multi‐functionality of defence traits, and herbivore selection pressure. Evidence from recent physiological studies is highlighted to shed light on the underlying molecular mechanisms involved in the regulation and activation of these developmental changes. Overall, our goal is to promote new research avenues that would provide evidence for the factors that have promoted the evolution of this complex lifetime phenotype. Future research focusing on the questions and approaches identified here will advance the field and shed light on why defence traits shift so dramatically across plant ontogeny, a widespread but poorly understood ecological pattern.     

Effects of precipitation and microorganisms on persistence of buried seeds: a case study of 11 species from the Loess Plateau of China

Plant and Soil - Mine tailings are challenging substrates for ecological restoration, as the establishment of diverse native plant communities can be constrained by a range of edaphic factors....     

根际微生物调控植物根系构型研究进展

根系构型是最重要的植物形态特征之一,具有可塑性,既由遗传因素控制,又受到许多环境因子的调控。近年的大量研究表明,根际微生物能够调控植物的根系构型,进而影响植物的一系列生理与生态过程。综述丛枝菌根真菌(AMF)、根瘤菌、植物根际促生菌(PGPR)等重要根际微生物类群对植物根系构型的调控模式以及相应的调控机理,并对进一步的研究进行了展望,旨在为今后的相关研究和实际应用提供参考。     

Effects of plant traits on ecosystem and regional processes: a conceptual framework for predicting the consequences of global change

Human activities are causing widespread changes in the species composition of natural and managed ecosystems, but the consequences of these changes are poorly understood. This paper presents a conceptual framework for predicting the ecosystem and regional consequences of changes in plant species composition. Changes in species composition have greatest ecological effects when they modify the ecological factors that directly control (and respond to) ecosystem processes. These interactive controls include: functional types of organisms present in the ecosystem; soil resources used by organisms to grow and reproduce; modulators such as microclimate that influence the activity of organisms; disturbance regime; and human activities. Plant traits related to size and growth rate are particularly important because they determine the productive capacity of vegetation and the rates of decomposition and nitrogen mineralization. Because the same plant traits affect most key processes in the cycling of carbon and nutrients, changes in plant traits tend to affect most biogeochemical cycling processes in parallel. Plant traits also have landscape and regional effects through their effects on water and energy exchange and disturbance regime.     

陆地生态系统植被氮磷化学计量研究进展

因化学功能的耦合和元素的不可替代性, 植物对N、P的需求和利用存在严格的比例。植物N、P化学计量在不同功能群、生长地区、生长季、器官之间以及环境梯度下存在明显的变化规律。多数研究从N、P浓度、N:P及N、P间异速指数等角度分析了植物化学计量变化规律, 并探讨其在全球范围内的具体数值。为增进对植物响应全球变化的理解, 该文综述了N、P化学计量的影响因素及其机理的最新研究进展, 并指出未来拟重点研究的方向。     

Factors determining distributions of tree species and plant functional types

Plant functional types have been identified by the International Geosphere Biosphere Program as functionally similar basic plant types, especially trees, as needed for global ecological modeling. Based to some extent on an earlier set of pheno-physiognomically defined plant types, a Global Biome Model was produced but has not satisfied all the desired functional criteria posed by IGBP physiologists and modelers. This paper asks two questions: what are the main environmental factors which limit terrestrial plant types, especially tree types; and how many types of potential vegetation are needed to cover the world's terrestrial vegetation patterns? Based on the main environmental factors recognized, a model of world potential dominant vegetation types was produced and used to estimate the minimal number of vegetation types needed. The resulting set of 40 potential dominant vegetation types may serve as an initial basis for a structural-functionally based set of world plant functional types.     

Symbiotic microorganisms, a key for ecological success and protection of plants

Plant-associated microbial diversity encompasses symbionts, protecting their host against various aggressions. Mycorrhizal and rhizospheric microorganisms buffer effects of soil toxic compounds and soil-borne pathogens. Endophytic bacteria and fungi, some of which are vertically inherited through seeds, take part in plant protection by acting directly on aggressive factors (mainly pathogens and herbivores) or by enhancing plant responses. Plant protective microbial symbionts determine the ecological success of plants; they drastically modify plant communities and related trophic webs. This review suggests approaches to improve the inventory of diversity and functions of in situ plant-associated microorganisms.     

植物生长调节剂的研究及应用进展

植物生长调节剂是合成植物激素,其可以调节植物的代谢和生理功能,并且已广泛用于农业、林业和其他领域。而植物生长调节剂本身存在的毒副作用所引起的安全问题也不容忽视,在使用调节剂时应保证其安全性和有效性。文章概述了植物生长调节剂的种类、作用功效、国内外植物生长剂的研究和应用情况及在使用中存在的问题,分析了调节剂药效的影响因素,就植物生长调节剂的进一步应用提出了建议,进行了展望,并对其应用于生态修复领域的可行性进行了分析。植物生长调节剂在使用时应注意:(1)适时适量;(2)多种药型谨慎搭配,科学调控植物生长剂的使用;(3)植物生长调节剂不能随意与农药搭配以避免不良反应的发生。     

青藏高原北部戈壁植物群落物种、功能与系统发育β多样性分布格局及其影响因素

戈壁荒漠广泛分布于全球干旱和极旱区域, 是我国陆地生态系统的重要组成部分。由于自然环境恶劣和交通条件限制, 目前有关戈壁植物群落物种、功能和系统发育等多维度β多样性形成机制的系统研究还很缺乏, 严重制约着对戈壁植物多样性维持机制的认知。本文以青藏高原北部61个典型戈壁生境植物群落为研究对象, 通过构建系统发育树和测量8个关键功能性状, 获取戈壁生境的物种、功能和系统发育β多样性, 比较3个维度β多样性格局与零模型的差异, 同时量化环境距离和地理距离对其的相对影响, 以探讨戈壁植物多样性的形成机制。结果显示: (1)戈壁植物的物种、功能和系统发育β多样性均表现出显著的距离衰减效应; (2)戈壁植物的物种、功能和系统发育β多样性均表现为非随机的格局; (3)由于功能性状趋同进化, 植物功能和系统发育β多样性变化趋势并不一致; (4)环境差异对植物3个维度β多样性均有着比空间距离更为重要的影响, 且土壤含水量、地表砾石盖度等局域生境因素的影响比气候更为强烈。以上结果表明, 戈壁植物的β多样性可能主要由局域生境过滤作用控制, 且不同维度的β多样性分布格局并不一致。     

植物次生代谢基因工程

植物次生代谢基因工程,是利用基因工程技术对植物次生代谢途径的遗传特性进行改造,进而改变植物次生代谢产物。植物次生代谢基因工程的出现是人类对次生代谢途径的深入了解和分子生物学向纵深发展的结果,同时它又促进了次生代谢分子生物学的发展。调控因子的应用和多基因的协同转化为植物次生代谢基因工程拓宽了思路。从次生代谢图谱、植物基因工程策略和植物转基因方法等方面对植物次生代谢的基因工程研究进展做一简要概述。     

Defensive Traits in Young Pine Trees Cluster into Two Divergent Syndromes Related to Early Growth Rate

The combination of defensive traits leads to the evolution of ‘plant defense syndromes’ which should provide better protection against herbivores than individual traits on their own. Defense syndromes can be generally driven by plant phylogeny and/or biotic and abiotic factors. However, we lack a solid understanding of (i) the relative importance of shared evolution vs. convergence due to similar ecological conditions and (ii) the role of induced defense strategies in shaping defense syndromes. We investigate the relative roles of evolutionary and ecological factors shaping the deployment of pine defense syndromes including multiple constitutive and induced chemical defense traits. We performed a greenhouse experiment with seedlings of eighteen species of Pinaceae family, and measured plant growth rate, constitutive chemical defenses and their inducibility. Plant growth rate, but not phylogenetic relatedness, determined the deployment of two divergent syndromes. Slow-growing pine species living in harsh environments where tissue replacement is costly allocated more to constitutive defenses (energetically more costly to produce than induced). In contrast, fast-growing species living in resource-rich habitats had greater inducibility of their defenses, consistent with the theory of constitutive-induced defense trade-offs. This study contributes to a better understanding of evolutionary and ecological factors driving the deployment of defense syndromes.     

Relationship among some ecological factors and chemical composition of Ajuga chamaecistus Ging. plant species

Ajuga chamaecistus belongs to Lamiaceae plant family. Plant samples were collected from four habitats during vegetative and flowering periods for comparing the essential oil yield and composition. After drying, the essential oil was extracted by distillation method. Essential oil yields of plants in four habitats were calculated which the analysis and identification of essential oil composition was performed using GC and GC–MS. Ultimately, the PCA was used to determine the relationship between plant major components and environmental factors. The results showed that β-Pinene and Linalool compounds had the highest percentage of essential oil composition. Environmental factors including elevation, annual precipitation, mean annual temperature, annual evaporation, sand and clay content were identified as the most effective factors in the isolation of A. chamaecistus habitats. It appears that the difference between ecological and soil factors of four habitats can have a significant effect on the type and percentage of essential oil components.     

基于植物功能性状的生态学研究进展:从个体水平到全球尺度

植物功能性状是指能够反映植物碳获取、水分传递、养分循环等的重要生命活动的属性,包括植物生理、形态和物候等方面的特征。通过植物功能性状探讨物种分布格局、生长策略和存活机制及其对全球变化的响应与适应,是近年来生态学研究的热点之一。然而,不同尺度下植物功能性状与环境因子的关系存在差异,并且性状之间的关系也不尽相同。从物种、种群、群落、植被区系到全球尺度,围绕植物功能性状之间的相互关系及其对气候环境变化响应的热点问题进行了综述,梳理了近年来植物功能性状研究领域的进展,并讨论了目前植物功能性状研究的局限性和该领域未来的发展趋势。     

高寒草甸植物物种丧失对草原毛虫的影响

植物多样性是调控食物网结构和生态系统功能最重要的生物因素, 植物多样性丧失深刻影响食草动物, 但由于小型食草动物种群数量波动明显、统计随机性较大等困难, 我们对植物多样性丧失如何影响小型食草动物依然知之甚少。基于在青藏高原高寒草甸设置的长期植物物种剔除试验, 本研究于2016-2020年7-8月连续调查了植物物种剔除各处理中草原毛虫(Gynaephora alpherakiif)的数量, 分析了植物物种及功能群丧失对草原毛虫的影响。结果表明, 虽然时空差异及统计随机性是影响草原毛虫数量变化的主要因素, 但植物物种剔除介导的群落差异对草原毛虫数量的影响依然显著: (1)在各观测时段, 优势种线叶嵩草(Kobresia capillifolia)的丧失导致群落中草原毛虫数量显著减少; 禾草类物种丧失也会减少草原毛虫数量, 但其影响仅在8月显著; (2)杂类草物种丧失通过增加群落中禾草物种多度, 可增加草原毛虫数量; 豆科物种丧失使莎草增多, 也会增加草原毛虫数量; (3)各植物功能群部分物种剔除并未显著影响草原毛虫数量。本研究证实了高寒草甸中草原毛虫数量会因优势植物嵩草和禾草的多度减少或禾草物种丧失而显著减少, 但群落总生物量、个体数和物种丰富度、豆科多度以及各功能群植物同比减少, 都对草原毛虫数量没有明显影响。这些结果说明在随机作用主导下, 植物群落中的特定功能群相对多度(而非物种多样性)变化深刻影响草原毛虫适合度, 进而影响生态系功能及服务; 未来生物多样性研究及草地虫害生物防控中应更多考虑统计随机性及植物功能多样性对小型食草动物的影响。     

Seeing is believing? Comparing plant–herbivore networks constructed by field co‐occurrence and DNA barcoding methods for gaining insights into network structures

Plant–herbivore interaction networks provide information about community organization. Two methods are currently used to document pairwise interactions among plants and insect herbivores. One is the traditional method that collects plant–herbivore interaction data by field observation of insect occurrence on host plants. The other is the increasing application of newly developed molecular techniques based on DNA barcodes to the analysis of gut contents. The second method is more appealing because it documents realized interactions. To construct complete interaction networks, each technique of network construction is urgent to be assessed. We addressed this question by comparing the effectiveness and reliability of the two methods in constructing plant–Lepidoptera larval network in a 50 ha subtropical forest in China. Our results showed that the accuracy of diet identification by observation method increased with the number of observed insect occurrences on food plants. In contrast, the molecular method using three plant DNA markers were able to identify food residues for 35.6% larvae and correctly resolved 77.3% plant (diet) species. Network analysis showed molecular networks had threefold more unique host plant species but fewer links than the traditional networks had. The molecular method detected plants that were not sampled by the traditional method, for example, bamboos, bryophytes and lianas in the diets of insect herbivores. The two networks also possessed significantly different structural properties. Our study indicates the traditional observation of co‐occurrence is inadequate, while molecular method can provide higher species resolution of ecological interactions.     

植物功能性状与环境和生态系统功能

植物性状反映了植物对生长环境的响应和适应,将环境、植物个体和生态系统结构、过程与功能联系起来(所谓的“植物功能性状”)。该文介绍了植物功能性状的分类体系,综述了国内外植物功能性状与气候(包括气温、降水、光照)、地理空间变异(包括地形地貌、生态梯度、海拔)、营养、干扰(包括火灾、放牧、生物入侵、土地利用)等环境因素,以及与生态系统功能之间关系的研究进展,探讨了全球变化(气候变化和CO₂浓度升高)对个体和群落植物功能性状的影响。植物功能性状的研究已经取得很多成果,并应用于全球变化、古植被恢复和古气候定量重建、环境监测与评价、生态保护和恢复等研究中,但大尺度、多生境因子下的植物功能性状研究仍有待于加强,同时需要改进性状的测量手段;我国的植物功能性状研究还需要更加明朗化和系统化。     

A PCR method for detection of plant meals from the guts of insects

The feeding behaviour of insects is a difficult ecological interaction to study. To date, entomologists have used biochemical and molecular techniques to identify the meals of predatory insects. We present here a molecular approach to identifying the DNA of plant species in the insect gut using the ribulose bisphosphate carboxylase gene large subunit (rbcL). A reference collection of 23 plant species from the southern Jordan Valley, Israel, was genetically characterized and employed. Insects belonging to eight different families were collected in the field along with the plants upon which they were found. After collection and prior to analysis, these insects were isolated on the plants they were found upon in the laboratory. This was to ensure that the insects had only one plant meal in their gut, as multiple plant meals would require additional techniques like cloning. A blind study was performed, genetically confirming plant DNA to species level from the processed gut contents of the insects. All reference plant species could be differentiated using a 157 bp long fragment of the rbcL gene. Plant DNA was identifiable, and the meal of the respective insect was accurately determined in each case. Analyses using experimentally fed crickets, Gryllodes hebraeus, determined that plant DNA was still detectable by PCR up to 12 h post-ingestion. This research proposes the application of molecular techniques for the identification of herbivorous insect feeding behaviour to increase understanding of plant–insect interactions.     

MBF1调控植物热应答与生长发育分子机制研究进展

MBF1是一种进化上高度保守的转录共激活因子,存在于所有真核生物中,可通过连接基础转录机器组分与转录因子来激活基因转录。植物MBF1具有多种重要生物学功能,包括调控植物生长发育和逆境适应等。该文综述了植物MBF1分子结构与调控机制相关研究进展,重点总结了AtMBF1c参与植物热胁迫应答调控的分子机制。