植物引种驯化研究概述

植物引种驯化是植物学的一个分支学科,该学科与植物的迁地保护和当地的经济建设紧密相关,属于应用基础研究的范畴。但有关理论和方法的研究至今仍显得比较零碎,不够系统,判断植物引种驯化成功的标准尚不够明确。本文就植物引种驯化的概念和意义、主要理论和方法、影响其成败的因子、途径和程序、判断植物引种驯化成功的标准等进行了综述和探讨,并提出了植物引种驯化的展望。     

Aquatic plant diversity in four river floodplains: a comparison at two hierarchical levels

The present study focuses on the role ofenvironmental factors in plant diversity and community organization at both water-body and river floodplain levels. The cover of each plant species was measured at 841 sampling plots along 63 cut-off channels located in four river floodplains. Environmental variables were documented either at river level (suspended matter, water physico-chemistry, river slope) or at cut-off channel level (channel capacity, slope, substrate grain-size). At both river and cut-off channel levels, increasing slope (i.e. increasing erosion during floods) and decreasing nutrient-content of the water raise species richness and uniqueness (number of species found only in one river), according to hypotheses on the combined role of disturbances and productivity in biodiversity. Rivers that are not eroded during floods are nutrient-rich and present the lowest richness and uniqueness at the river level, but dewatering combined with high connectivity increase richness at the cut-off channel level.     

植物盐胁迫应答蛋白质组学研究的技术策略

土壤盐渍化是限制植物生长和分布的关键因素之一.揭示植物响应盐胁迫的分子机理是借助分子生物学手段提高植物耐盐性的基础,也是当前植物生理与分子生态学研究的热点问题.高通量的蛋白质组学技术体系包括双向电泳技术、蓝色自然胶电泳技术、双向荧光差异凝胶电泳技术、液相色谱技术,以及各种生物质谱技术,已经被广泛应用于植物应答盐胁迫研究,为解析植物耐盐分子机制提供了重要信息.本文综述了应用于植物盐胁迫响应蛋白质组学研究的技术策略.     

Top predator control of plant biodiversity and productivity in an old-field ecosystem

Abstract Predators can have strong indirect effects on plants by altering the way herbivores impact plants. Yet, many current evaluations of plant species diversity and ecosystem function ignore the effects of predators and focus directly on the plant trophic level. This report presents results of a 3‐year field experiment in a temperate old‐field ecosystem that excluded either predators, or predators and herbivores and evaluated the consequence of those manipulations on plant species diversity (richness and evenness) and plant productivity. Sustained predator and predator and herbivore exclusion resulted in lower plant species evenness and higher plant biomass production than control field plots representing the intact natural ecosystem. Predators had this diversity‐enhancing effect on plants by causing herbivores to suppress the abundance of a competitively dominant plant species that offered herbivores a refuge from predation risk.     

Effects of root herbivory by an insect on a foliar-feeding species,mediated through changes in the host plant

Summary The effects of root herbivory by larvae of the scarabaeid, Phyllopertha horticola, on the growth of Capsella bursa-pastoris were examined. Individuals of Aphis fabae were reared on the leaves to determine what effect, if any, root feeding has on the performance of this insect. The experiment was conducted under two watering regimes (low and high). Low watering and root feeding caused water stress in the plants and this was reflected in a reduction in vegetative biomass and an increase in the proportion of material allocated to reproduction. Supplying plants with ample water in the high treatment enabled the water stress caused by root herbivory to be offset, but not completely overcome. Low watering and root feeding caused an increase in aphid weight and growth rate, while root feeding also increased fecundity and adult longevity. These effects are attributed to an improvement in food quality, measured by total soluble nitrogen, and caused by amino acid mobilization due to the water stress. The implications of these results in agricultural and ecological situations are discussed.     

A new type of thermoluminometer: a highly sensitive tool in applied photosynthesis research and plant stress physiology

Here we describe a newly developed thermoluminescence measuring device that employs flash excitation, peltier heating, and light detection by channel photomultipliers (CPM). The new thermoluminometer is equipped with four sample holders for simultaneous measurements of thermoinduced light emission in the temperature range from -20 degrees C to +180 degrees C. It allows one to measure leaf samples, chloroplasts, thylakoids, algae, or even bioorganic material lacking chlorophyll by means of naturally induced or artificially applied chemilumigenic probes. The temperature range of the thermoluminometer allows one to analyse the thermoinduced radical pair recombination of photosystem II in the lower temperature region as well as chemiluminescence from lipid peroxidation in the higher temperature region. Hence, plant material can be assessed concerning both its photosynthetic and its oxidative stress status. Since the device is equipped with four sample holders and four CPM channels for simultaneous detection of thermoinduced light emission, it facilitates a high throughput. Therefore, the new device is interesting, not only in ecophysiology, but also in the field of plant breeding, as it can be used to study the stress tolerance of various cultivars of cultural crop plants.     

Evolution of C4 plants: a new hypothesis for an interaction of CO2 and water relations mediated by plant hydraulics

C(4) photosynthesis has evolved more than 60 times as a carbon-concentrating mechanism to augment the ancestral C(3) photosynthetic pathway. The rate and the efficiency of photosynthesis are greater in the C(4) than C(3) type under atmospheric CO(2) depletion, high light and temperature, suggesting these factors as important selective agents. This hypothesis is consistent with comparative analyses of grasses, which indicate repeated evolutionary transitions from shaded forest to open habitats. However, such environmental transitions also impact strongly on plant-water relations. We hypothesize that excessive demand for water transport associated with low CO(2), high light and temperature would have selected for C(4) photosynthesis not only to increase the efficiency and rate of photosynthesis, but also as a water-conserving mechanism. Our proposal is supported by evidence from the literature and physiological models. The C(4) pathway allows high rates of photosynthesis at low stomatal conductance, even given low atmospheric CO(2). The resultant decrease in transpiration protects the hydraulic system, allowing stomata to remain open and photosynthesis to be sustained for longer under drying atmospheric and soil conditions. The evolution of C(4) photosynthesis therefore simultaneously improved plant carbon and water relations, conferring strong benefits as atmospheric CO(2) declined and ecological demand for water rose.     

Genetics of the ability of Phyllotreta nemorum larvae to survive in an atypical host plant, Barbarea vulgaris ssp. arcuata

A polymorphism in host plant exploitation has been discovered in the flea beetle, Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) where one resistant population is able to use Barbarea vulgaris R.Br. ssp. arcuata (Opiz.) Simkovics (Brassicaceae) as a host plant while a susceptible population is not. Crosses (F1, F2, and backcrosses) between the two flea beetle populations were made, and survival of the progeny on B. v. ssp. arcuata was measured. The ability of P. nemorum larvae to survive in this plant species depended on the presence of major, dominant genes (R-genes). The two most abundant R-genes in the resistant flea beetle population were X- and Y-linked, respectively. The use of B. v. ssp. arcuata as a natural host plant by the resistant population of P. nemorum seems to be an extension of the host plant range of the species. The role of sex-linked genes in the evolution of host range is discussed.