Cotyledon damage at the seedling stage affects growth and flowering potential in mature plants

Seedling herbivory is an important selective filter influencing patterns of plant community composition. Nevertheless, while many of the mechanisms governing seedling selection by herbivores are well established, the effects of tissue loss at the seedling stage on subsequent plant development are poorly understood. Here we examined how the removal of 50 or approximately 100% of cotyledon area from 7-d-old chalk grassland seedlings affected subsequent plant growth and flowering over a 100-d period. Cotyledon damage had a significant effect on growth during the establishment phase for six of the nine species. For two species, significant effects on plant growth were manifest in 100-d-old plants. Of the five species that flowered, three developed fewer inflorescences or flowered later as a consequence of cotyledon damage suffered as a seedling. Our results show that, in addition to the direct effect of herbivory on seedling mortality, more subtle sublethal effects may also influence plant establishment. Reduced growth as a result of cotyledon damage may have implications for plant competition during the establishment phase, and on subsequent reproductive success at maturity.     

Combined effects of climate and biotic interactions on the elevational range of a phytophagous insect

1. The ranges of many species have expanded in cool regions but contracted at warm margins in response to recent climate warming, but the mechanisms behind such changes remain unclear. Particular debate concerns the roles of direct climatic limitation vs. the effects of interacting species in explaining the location of low latitude or low elevation range margins. 2. The mountains of the Sierra de Guadarrama (central Spain) include both cool and warm range margins for the black-veined white butterfly, Aporia crataegi, which has disappeared from low elevations since the 1970s without colonizing the highest elevations. 3. We found that the current upper elevation limit to A. crataegi's distribution coincided closely with that of its host plants, but that the species was absent from elevations below 900 m, even where host plants were present. The density of A. crataegi per host plant increased with elevation, but overall abundance of the species declined at high elevations where host plants were rare. 4. The flight period of A. crataegi was later at higher elevations, meaning that butterflies in higher populations flew at hotter times of year; nevertheless, daytime temperatures for the month of peak flight decreased by 6.2 degrees C per 1 km increase in elevation. 5. At higher elevations A. crataegi eggs were laid on the south side of host plants (expected to correspond to hotter microclimates), whereas at lower sites the (cooler) north side of plants was selected. Field transplant experiments showed that egg survival increased with elevation. 6. Climatic limitation is the most likely explanation for the low elevation range margin of A. crataegi, whereas the absence of host plants from high elevations sets the upper limit. This contrasts with the frequent assumption that biotic interactions typically determine warm range margins, and thermal limitation cool margins. 7. Studies that have modelled distribution changes in response to climate change may have underestimated declines for many specialist species, because range contractions will be exacerbated by mismatch between the future distribution of suitable climate space and the availability of resources such as host plants.     

虫害诱导的植物挥发物:植物与植食性昆虫及其天敌相互作用的进化产物

综述了植物、植食性昆虫及其天敌相互作用的进化过程。虫害诱导的植物挥发物的特征和功能是植物-植食性昆虫-天敌之间长期进化的结果。在植物、植食性昆虫与天敌相互作用的进化过程中,3个不同营养级,包括植物、植食性昆虫和天敌有着各自的调节和利用虫害诱导的植物挥发物的策略。但有一些问题,如通过实验研究得出的诱导防御在田间是否真正能起到保护作用等需进一步研究、阐明。     

植物与病原菌互作的蛋白质组学研究进展

深入认识植物与病原菌的识别方式、亲和性或非亲和性的互作模式,对于揭示植物-病原菌互作机制研究具有重要意义.利用蛋白质组学方法研究病原菌侵染植物过程,分析相关的基因和蛋白,有助于从分子水平上探究植物-病原菌相互作用机制.本文概述了植物-病原菌的互作机制,系统介绍了差异蛋白质组学分析方法在植物-病原真菌、植物-病原细菌两类互作系统中的应用,分析了植物与病原菌互作过程中可能涉及的差异表达功能蛋白,并对当前蛋白质组学技术在植物与病原菌互作研究中存在的诸多问题进行了探讨.     

Ecological and Evolutionary Interactions between Wild Crucifers and Their Herbivorous Insects

Abstract Insects feeding on ten species of wild crucifer were investigated. Differences in host plant range and insect community structure were examined with regard to anti-herbivore defense mechanisms. Most of the crucifer species deterred insect herbivory by disappearing in the summer or by lowering their intrinsic quality as food for insects. Species with these defense mechanisms were exploited by only a few specialized herbivorous insects that seemed to have counter defenses. The plants without these defense mechanisms were used by many herbivorous insect species. Rorippa indica lacked direct defenses, but supported a low total density of herbivore individuals. This crucifer has an indirect defense mechanism: ants attracted to floral nectar defended the plant from deleterious herbivores. Crucifers that disappeared seasonally lacked other anti-herbivore defense mechanisms. This suggests that the phonological response is an alternative other responses to herbivore attack.     

Ant associations in the Neotropical shrub Turnera subulata (Turneraceae): Costs or benefits to the host plant?

The results of ecological interactions depend on the costs and benefits involved in different ecological contexts. Turnera subulata is a shrubby plant with extrafloral nectaries that are associated with ants. Here, we test the hypotheses that the association between T. subulata and ants results in: (i) positive effects on host plant growth and reproduction; (ii) plant herbivory reduction and (iii) inhibition of the host plant visitation by beneficial organisms. Thirty experimental plots were established in northeastern Brazil, either in association with ants or without ants (N = 15 plots/treatment), with four plants each (total 120 plants). Vegetative growth (plant height and number of leaves), reproductive investment (flowers and fruits), herbivory rates and numbers of beneficial visitors were quantified during all phenological stages of the host plant. Data were analysed using generalized linear mixed models. At the host plant maturation stage, we found a trade‐off between growth and reproduction. Plants with ants had lower mean height; however, they invested more in reproduction (a higher number of flowers and fruits) compared to plants without ants. During the flowering stage, the abundance of sucking herbivores was higher in plots without ants but chewing herbivore abundance increased in the maturation stage in plots with ants. The cumulative proportion of leaves with herbivore damage did not differ between treatments, and the presence of ants reduced the number of beneficial visitors (e.g. pollinators and natural enemies) to the host plants. Our results show that association with ants results in some costs for the host plant, however, these costs appear to be offset by the defensive role of ants, which favours plant reproductive investment. In general, our results help to elucidate mechanisms involved in trophic interactions within the complex network of interactions involving ants and plants.