百日草链格孢菌毒素对加拿大一枝黄花叶片伤害的生理生化研究

采用植物抗性生理和光合生理的分析测定技术,研究了分离自罹病苍耳植株上的百日草链格孢菌产生的毒素对加拿大一枝黄花叶组织细胞膜透性、丙二醛(M DA)含量、光合能力以及过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和过氧化氢酶(CAT)活性的影响.结果表明,百日草链格孢菌毒素使加拿大一枝黄花叶组织细胞膜透性上升,膜脂过氧化加强,M DA含量上升;叶片的POD、APX和CAT的活性均较对照降低,其光合作用明显地受到抑制.说明百日草链格孢菌毒素具有防除加拿大一枝黄花的潜力.     

epi-Cubebanes from Solidago canadensis

GC-MS of the essential oil prepared by hydrodistillation of the green parts of a specimen of Solidago canadensis collected near Katowice, Poland, revealed two new sesquiterpene hydrocarbons. Their EI mass spectra resembled the mass spectrum of beta-ylangene (1) but the retention indices of the new compounds differed markedly from this known compound. After isolation of the new compounds by preparative GC their investigation by one- and two-dimensional NMR techniques resulted in the identification of 6-epi-alpha-cubebene (2) (minor constituent, 1.5%) and 6-epi-beta-cubebene (3) (major constituent, 20.5%).     

Response of Solidago canadensis clones to competition

Summary Transplants of ten Solidago canadensis clones were grown under high and low competition in the field to determine whether clones differed in survival, growth, and reproduction under natural conditions. Transplants had higher probability of survival and flowering and were larger in all measures of size when competition was experimentally reduced. Clones differed in almost all these measures of success, but only when variance among transplants within clones was reduced by excluding transplants that experienced heavy herbivore damage. Differences among clones were more apparent under low competition than under high competition, despite higher coefficients of variation within clones under low competition. Adjusting transplant size for initial size (parent ramet rhizome mass) did not change these results, although clones did differ in parent rhizome mass. All of these results suggest that there is little potential for selection to discriminate among these clones. Despite the strong differences in transplant performance between the competition treatments and among clones, the clones did not differ in competitive ability-almost none of the clone x competition interactions were significant. In addition, the measures of success of each clone were usually positively correlated between the high and low competition treatments, suggesting there were no tradeoffs between performance under high and low competition for these clones.     

Physiological acclimation of two psammophytes to repeated soil drought and rewatering

To understand physiological acclimation of psammophyte to repeated soil drought and rewatering, two psammophytes (Setaria viridis and Digitaria ciliaris) were subjected to three cycles of soil drought and rewatering. The response process of leaf relative water content (RWC), membrane permeability, lipid peroxidation, gas exchange characteristics, antioxidant enzymes, soluble protein, and free proline was examined. Leaf RWC, the net photosynthesis rate, stomatal conductance, and water use efficiency decreased, while membrane permeability, lipid peroxidation, intercellular CO₂ concentration, soluble protein, and free proline increased during three soil drought periods for both psammophytes. These physiological characteristics were recovered to the control levels following rewatering for 4 days. However, activities of SOD, CAT, and POD were induced continuously under soil drought conditions, and remained higher than those in the control throughout the whole experiment period, which agrees with our hypothesis that drought hardening activates defensive systems of both psammophytes continuously. Decreasing level of leaf RWC and increasing levels of leaf membrane permeability and lipid peroxidation were suppressed with increasing the number of drought cycles, suggesting that drought hardening alleviates damages of both psammophytes and improves their drought tolerance and acclimation to soil drought conditions in the future. Additionally, the photosynthesis decreased more slowly in the subsequent drought cycles than in the first cycle, allowing both psammophytes to maximize assimilation in response to repeated soil drought conditions. Thus, both psammophytes acclimatize themselves to repeated soil drought.     

加拿大一枝黄花在中国的潜在入侵区预测

加拿大一枝黄花Solidago canadensis是原产于北美的菊科Asteraceae多年生草本植物, 上世纪30年代引入我国, 现广泛分布于我国东部地区的部分省市, 并已成为该区域的农业和环境杂草。为了预测加拿大一枝黄花在我国的潜在分布区, 本研究采用相同气候方法对其进行了估测。我们用加拿大一枝黄花的原产地——美国的气候参数作为参照, 将其与我国各地气象站的气候数据进行匹配。结果表明, 加拿大一枝黄花在我国的潜在分布区的纬度跨度为25°–50°, 所以其潜在的入侵区将远大于目前的实际分布区, 甚至东北的部分地区也将适宜于该物种的生长。据此, 我们建议相关管理部门应加强该物种的监测工作, 以防其进一步向目前入侵区以外的周边地区蔓延。     

加拿大一枝黄花入侵的细胞学机制

对入侵植物加拿大一枝黄花(Solidago canadensis L.)和同属土著种一枝黄花(Solidago decurrens Lour.)的染色体计数,并对核型进行了分析.实验结果:加拿大一枝黄花染色体数目为2n=54,核型公式为k(2n)=6x=54＝46m 8sm(0-6SAT),核型类型为2A型;一枝黄花染色体数目为2n=18,核型公式为k(2n)=2x=18=16m 2sm(0-2SAT),核型类型为1A型.通过对一枝黄花属(Solidago L.)植物染色体数目的统计分析,判断该属的染色体基数为9.通过对多倍体基因表达导致植物适应进化的讨论得出:多倍体是入侵植物特征,可能是植物入侵的内在机制.     

Polyploidization-driven differentiation of freezing tolerance in Solidago canadensis

Solidago canadensis, originating from the temperate region of North America, has expanded southward to subtropical regions through polyploidization. Here we investigated whether freezing tolerance of S. canadensis was weakened during expansion. Measurement of the temperature causing 50% ruptured cells (LT₅₀) in 35 S. canadensis populations revealed ploidy-related differentiation in freezing tolerance. Freezing tolerance was found to decrease with increasing ploidy. The polyploid populations of S. canadensis had lower ScICE1 gene expression levels but more ScICE1 gene copies than the diploids. Furthermore, more DNA methylation sites in the ScICE1 gene promoter were detected in the polyploids than in the diploids. The results suggest that promoter methylation represses the expression of multi-copy ScICE1 genes, leading to weaker freezing tolerance in polyploid S. canadensis compared to the diploids. The study provides empirical evidence that DNA methylation regulates expression of the gene copies and supports polyploidization-driven adaptation to new environments.     

Reproductive biology in an invasive plant Solidago canadensis

Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural conditions,S.canadensis allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed size.In addition,naturalized populations have a great capacity to grow clonally with underground stems.S.canadensis has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in China.In order to understand the reproductive characteristics of S.canadensis and effectively control its spread,we examined soil conditions,seed characteristics,seed germination and the capacity for asexual reproduction in different plant parts.We investigated the population dispersion of S.canadensis in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of S.canadensis.We also compared differences in the root systems of S.canadensis and composite exotic weeds.The following results were obtained:1)Under natural conditions,the germination season of S.canadensis lasts from March to October,with a peak from April to May.Vegetative growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought stress.On the other hand,the rainy season proves suitable for seed germination.Most S.canadensis flower between September and January,and fruit in late October.A mature plant can produce about 20000 seeds.The mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60% to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)S.canadensis seeds have a wide tolerance for different values of pH,salinity and soil moisture.The mean percent germination of seeds is 30% under suitable conditions.The results of seed germination under various environmental stresses and investigation of soil conditions indicate that well-aerated,slightly acidic soils with low salinity are suitable for the growth of S.canadensis.Additionally,S.canadensis has a high tolerance for contamination by heavy metal elements including Zn,Cu and Pb,but has low accumulation coefficients for these elements.3)S.canadensis reproduces asexually via underground rhizomes and nodes on the stem base to recruit new individuals,and in plants that experience mechanical damage,this reproductive strategy is used to produce clonal shoots.The capacity for asexual reproduction among different plant parts rank as follows:underground parts＞stem-base (20 cm)＞stem-base (30 cm)＞stem-base (45 cm)＞stem.Further,with increasing mechanical damage,the quantity of shoots produced by the plant decreases.4)The morphological parameters of the root system of S.canadensis including length,surface area,volume,and average diameter are greater than for composite exotic weeds.These parameters indicate that S.canadensis has the physiological potential to widely invade China.5)The aboveground growth rate and most of the underground morphological parameters vary remarkably among the seasons,with a peak normally occurring in September.In August,a fraction of the energy in leaves and stems is allocated underground to increase fine root growth and water uptake during hot weather.Additionally,the seasonal dynamics of the underground morphological parameters and the caloric values of different organs of S.canadensis enhance its reproductive ability.Based on the results above,we conclude that S.canadensis has great invasive potential in China.We suggest that urgent measures should be taken to control its further spread,and to minimize its impact on local plant diversity.     

Four major saponins from Solidago canadensis.

Four new bisdesmosidic saponins each containing eight carbohydrate units were isolated from Solidago canadensis. GC, GC-MS, FABMS analysis and mainly the use of 2D NMR techniques allowed their identification as bayogeninglycosides (canadensissaponins 1-4) 3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D- apio-D-furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl- (1----]-bayogenin; -(1----2)-[beta-D-apio-D-furanosyl-(1----3)]-ara- binopyranosyl-(1----]-bayogenin; -[alpha-L-rhamnopyranosyl-(1----3)]-beta- D-6-deoxyglucopyranosyl-(1----]-bayogenin and - [alpha-L-rhamnopyranosyl- (1----3)]-arabinopyranosyl-(1----]-bayogenin.     

谷子对干旱胁迫的生理生态响应

干旱少雨严重限制了我国西北地区谷子的产量,为明确谷子响应干旱的生理特征,以干旱敏感谷子品种安04和不敏感品种豫谷1号以及xiaomi为材料,通过盆栽试验,研究了谷子不同生育期叶片光合参数、叶绿素含量、非结构性碳、β-淀粉酶基因表达对水分亏缺的响应。结果表明,正常水分条件下安04产量高于豫谷1号,干旱胁迫严重限制了两个谷子品种的产量形成,安04和豫谷1号分别减产71.2%和56.0%,豫谷1号产量显著高于安04。正常水分条件下,安04具有比豫谷1号更高的净光合速率（P<0.05）,干旱胁迫下,豫谷1号叶片净光合速率显著高于安04;叶片蒸腾速率结果同光合结果一致。干旱条件下,豫谷1号具有更高的叶片相对含水量。干旱胁迫显著降低了两个谷子品种花期的叶绿素a、叶绿素b及总叶绿素含量,且安04降低幅度均大于豫谷1号。干旱胁迫均显著增加了豫谷1号拔节期和开花期的叶片可溶性糖含量,而安04叶片可溶性糖含量并没有发生显著性变化,同时干旱胁迫显著增加了豫谷1号β-淀粉酶基因SiBAM1的表达水平。施用β-淀粉酶活性抑制剂α-环糊精,xiaomi叶片可溶性糖及脯氨酸含量显著降低,进一步加重了干旱对xiaomi的生长抑制。综上所述,干旱胁迫诱导谷子β-淀粉酶基因表达和β-淀粉酶活性升高从而水解淀粉形成可溶性糖,高可溶性糖含量对谷子提高抗旱性起重要作用。     

入侵杂草加拿大一枝黄花的化感作用

测定了加拿大一枝黄花水浸提液对辣椒、番茄、萝卜、长梗白菜和小麦等五种经济作物种子萌发和生长的影响。结果表明:(1)高浓度的加拿大一枝黄花水浸提液对几种作物种子萌发和生长有明显的抑制作用,而低浓度下则对萝卜、长梗白菜和番茄的种子生长有一定的促进作用;(2)加拿大一枝黄花茎叶部分水浸提液的抑制作用要强于地下部分。     

Slowly developing drought stress increases photosynthetic acclimation of Catharanthus roseus

Our understanding of plant responses to drought has improved over the decades. However, the importance of the rate of drought imposition on the response is still poorly understood. To test the importance of the rate at which drought stress develops, whole-plant photosynthesis (P(net) ), respiration (R(dark) ), daily carbon gain (DCG), daily evapotranspiration (DET) and water use efficiency (WUE) of vinca (Catharanthus roseus), subjected to different drought imposition rates, were investigated. We controlled the rate at which the substrate dried out with an automated irrigation system that allowed pot weight to decrease gradually throughout the drying period. Fast, intermediate and slow drying treatments reached their final pot weight [500 g, substrate water content (θ) ≈ 0.10 m3 m(-3) ] after 3.1, 6.6 and 10 days, respectively. Although all drying treatments decreased P(net) and R(dark) , slow drying reduced P(net) and R(dark) less than fast drying. At a θ < 0.10 m3 m(-3) , DCG and DET in the slow drying treatment were reduced by ≈50%, whereas DCG and DET in the fast drying treatment were reduced by 85 and 70% at a θ of 0.16 m(3) m(-3) . Plants exposed to slow drought imposition maintained a high WUE, even at θ < 0.10 m3 m(-3) . Overall, physiological responses to low θ were less severe in plants subjected to slow drying as compared with fast drying, even though the final θ was lower for plants exposed to slow drying. This suggests that the rate at which drought stress develops has important implications for the level of acclimation that occurs.     

马尾松菌根化苗木对干旱的生理响应及抗旱性评价

采用温室盆栽方法,研究了持续干旱及复水处理后,接种褐环乳牛肝菌7、牛肝菌1、鸡油菌、彩色豆马勃和土生空团菌的马尾松苗木生理变化,并对菌根化苗木进行抗旱性评价.结果表明:在持续干旱条件下,马尾松苗木的丙二醛和相对质膜透性随之增加,但菌根化苗木的丙二醛和相对质膜透性均显著低于未接种苗木(对照);复水后,菌根化苗木中丙二醛和质膜透性较对照迅速降低.在持续干旱胁迫前21 d,马尾松苗木超氧阴离子自由基产生速率增加,同时也诱导了菌根化苗木中过氧化物歧化酶、过氧化物酶和硝酸还原酶活性显著增加.随着胁迫时间的延长,苗木复水后的恢复能力各异.在胁迫14 d复水后,苗木过氧化物歧化酶、过氧化物酶和硝酸还原酶的活性均得以恢复.菌根化苗木抗旱性的强弱为牛肝菌7＞牛肝菌1＞鸡油菌＞土生空团菌＞彩色豆马勃.过氧化物歧化酶和丙二醛与马尾松菌根化苗木抗旱性关联度较大,可以作为抗旱鉴定的主要指标.     

彩叶草对模拟干旱胁迫的生理响应

采用盆栽试验,对彩叶草进行PEG-6000浓度为0(对照)、5%、10%、15%、20%(W/V)模拟干旱胁迫,研究在干旱胁迫下彩叶草的生长、渗透调节能力及抗氧化酶活性的变化。结果表明:与对照相比,随着PEG-6000浓度的增加,鲜质量、干质量、含水量、水势、根系脱氢酶活性、无机离子含量包括K+、Na+、Ca2+、Mg2+等均呈下降趋势;NO-3含量呈先下降后上升趋势;硝酸还原酶活性、可溶性蛋白含量、可溶性糖含量、超氧化物歧化酶活性均呈先上升后下降趋势;脯氨酸含量、游离氨基酸含量、过氧化物酶活性、过氧化氢酶活性、超氧阴离子(O-2·)产生速率、质膜透性则呈上升趋势。因此,模拟干旱胁迫对彩叶草生长有抑制作用,且随着PEG-6000浓度增加,其生长受抑制和水分胁迫程度加重;模拟干旱胁迫下,彩叶草不积累K+、Na+、Ca2+、Mg2+和NO-3等无机离子进行渗透调节,而积累脯氨酸、可溶性蛋白、可溶性糖、游离氨基酸等有机小分子物质进行渗透调节,但这4种小分子物质增加幅度不尽相同;轻度模拟干旱胁迫虽增强彩叶草抗氧化酶活性,但仍表现轻度的氧化伤害;重度模拟干旱胁迫加重彩叶草氧化伤害。研究结果可为彩叶草耐旱生理机制的研究积累资料,也为其节水型栽植和养护提供依据。     

甘薯愈伤组织对干旱胁迫和盐胁迫的生理反应对比

研究干旱胁迫和盐胁迫对“芦选一号”。日‘薯愈伤组织可溶性蛋白、可溶性糖、脯氨酸含量、SOD活性等的影响,从而在细胞水平上探讨甘薯抵御渗透胁迫的生理机制。并分析甘薯细胞对干旱处理（PEG-6000）和盐处理（NaCl）的反应差异。结果表明,可溶性蛋白质含量在干旱胁迫下缓慢升高,在轻度和中度盐胁迫的生长前期和中期有较大幅度的上升。但后期下降,表明短时间盐胁迫下,Na^＋可能促进可溶性蛋白的合成;MDA在重度干旱胁迫下的含量显著低于重度盐胁迫,而SOD活性显著高于盐胁迫。表明在盐胁迫下细胞膜透性增加的主要原网是膜脂过氧化作用。干旱处理则是PEG-6000脱水的直接结果;重度干旱胁迫下,可溶性糖含量在短期内迅速升高,然后下降,而脯氨酸含量则在胁迫中后期迅速上升。脯氨酸可能有补偿可溶性糖含量降低的作用。     

Physiological responses of wheat to drought stress and its mitigation approaches

Drought is a polygenically controlled stress and a major agricultural risk that reduces crop productivity and limits the successful insight of land potential throughout the world. This review article has been divided into two parts, i.e., effect of drought stress on physiology of wheat and potential drought mitigation approaches. In the first part, physiological responses of wheat to stress were discussed. Cell membrane stability, relative water content, early maturity, decreased leaf area, small plant size, increased dry weight and root–shoot ratio, and the whole-plant transpiration rate response to enhanced atmospheric vapor pressure deficit are physiological traits associated with drought tolerance in wheat. Reduction of relative water content closes stomata and thereby reduces stomatal conductance. Osmotic adjustment improves drought tolerance by allowing cell enlargement, plant growth, and stomata to stay partially open and by maintaining CO₂ fixation under severe water deficit. The wheat plant accumulates several organic and inorganic solutes in its cytosol to lessen its osmotic potential for maintenance of cell turgor. Drought affects photosynthesis negatively by changing the inner structure of chloroplasts, mitochondria, and chlorophyll content and minerals. Destruction of the photosystem II (PSII) oxygen releasing complex and reaction center can disturb production and use of electrons, causing lipid peroxidation of cell membrane through the production of reactive oxygen species. In the second part, drought mitigation approaches were discussed. Seed, drought, bacterial, and hormonal priming are common approaches used to lessen the effects of water deficit. Physiological trait-based breeding, molecular breeding, marker-assisted backcrossing, aerial phenotyping, water budgeting, and resource allocation are modern approaches used to develop drought tolerant wheat cultivars. Wheat genotypes produced as a result of a combination of all these methodologies will increase food security regarding the currently changing climate.     

Physiological response of non-Bt and Bt cotton to short-term drought stress

Drought stress triggered the accumulation of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) both in non-Bt and Bt cotton with simultaneous production of antioxidant enzymes. And there was no significant difference between non-Bt and Bt cotton under drought stress. In contrast to this, we observed a significant reduction of Bt toxin proteins under 72 h of drought stress in Bt cotton.     

南方菟丝子对加拿大一枝黄花的寄生控制效应

以安全性较高的本土植物南方菟丝子和重要的外来入侵植物加拿大一枝黄花为材料,于温室中采用盆栽试验在湿润和半湿润条件下用南方菟丝子寄生不同生长阶段(幼苗阶段、过渡阶段和成株阶段)的加拿大一枝黄花植株,考察加拿大一枝黄花植株被寄生后的营养生长、光合生理、逆境生理等指标,探索适宜南方菟丝子寄生加拿大一枝黄花的最佳条件阈值。结果显示:(1)寄生处理与对照之间,加拿大一枝黄花株高、基径、生物量、叶绿素含量、光合速率、可溶性糖、丙二醛、脯氨酸等指标差异均显著;(2)幼苗组、过渡组被寄生加拿大一枝黄花的株高增量、基径增量、生物量、叶绿素含量、净光合速率均显著低于相应对照组,而其可溶性糖、丙二醛、脯氨酸含量均显著高于相应对照组;(3)在半湿润条件下,加拿大一枝黄花的株高、基径增量均小于湿润条件下植株,其净光合速率、叶绿素含量在幼苗组和过渡组均小于湿润条件下植株,而可溶性糖、丙二醛、脯氨酸含量在在幼苗组和过渡组均大于湿润条件下相应指标;(4)幼苗组、过渡组加拿大一枝黄花被寄生后无法正常开花结实,寄生幼苗组加拿大一枝黄花的南方菟丝子亦无法正常开花结实。研究表明,在湿润与半湿润地区,南方菟丝子可以寄生各生长阶段的加拿大一枝黄花,并对株高1.2 m以下的植株产生较强的寄生胁迫;寄生的最佳时间段为每年的4月到8月。