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1.
Salinization is an increasing land degradation issue in the Songnen Grassland of northern China. Effects of salinity and temperature on seed germination and seedling growth of Chloris virgata, a promising halophyte, and Digitaria sanguinalis, a widespread glycophyte were examined in six soil solutions (0, 50, 100, 150, 200 and 250 mm NaCl) and four temperatures (15, 20, 25 and 30°C). Germination percentages and rates of both species decreased significantly at higher salinities, but ungerminated seeds can recover germination upon supply of distilled water. Radicle length, seedling height and the total dry weight of both species generally decreased in a concentration‐dependent manner at 20°C and above as the salinity increased. However, at 15°C, the salt‐treated seedlings showed decreases with a similar magnitude for different salinities. Low salinities seem to stimulate germination and seedling growth of C. virgata compared with the control treatment. Both species were more sensitive to salinity during the seedling stage than the germination stage. Digitaria sanguinalis from the saline Songnen Grassland region seems to develop a halophyte‐like adaptive strategy to some extent. However, C. virgata may still dominate most hyperhaline areas due to its higher salt tolerance.  相似文献   

2.
Tall wheatgrass -Elymus elongatus (Host) Runemark- has long been used for forage production in temperate areas where salinity, alkalinity, waterlogging, or water scarcity hinder growth of other fodder species, and has a broad history of being included in revegetation programs of saline land and in wheat breeding programs. Despite its renown as a suitable species for unfavourable soil environments, the physiological mechanisms underlying its tolerance to abiotic stresses are scattered across the literature and this precludes answering the question that has motivated this review: how does tall wheatgrass endure inhospitable soil environments? The review starts with an outline of saline, alkaline and saline-alkaline soils, and their associated waterlogging or water scarcity events. This is followed by a delineation of the physiological mechanisms responsible for plant tolerance to such soils, with an emphasis on the mechanisms associated with tall wheatgrass. Briefly outlined, tall wheatgrass has shown evidence of possessing mechanisms to allow the continuity of water influx -where salinity or drought leads to reduced water availability-, strategies to avoid ion toxicity and to acquire essential nutrients, and ability to cope with high pH levels, waterlogging and excess reactive oxygen species produced as a consequence of stress. Seeking the answer to this inquiry, this review also contributes to the understanding of forage production and quality in these fragile soil environments.  相似文献   

3.
Drought stress is a major factor‐limiting grass growth. The production of reactive oxygen species (ROS) increases under stress conditions and causes cell oxidative damage. This study investigated the effect of sodium nitroprusside [a nitric oxide (NO) donor] treatment on drought stress in two turfgrass species, creeping bentgrass and tall fescue. Physiological characteristics such as relative water content (RWC), ion leakage, chlorophyll and proline content, and activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) were evaluated after 40 d drought stress and in the recovery stage. Results showed that nitric oxide (NO) treatment, especially 150 μm , could maintain significantly higher RWC and reduce ion leakage under drought stress conditions in both species. Furthermore, both turfgrass species showed higher chlorophyll and proline content after drought stress period when sprayed with NO, while chlorophyll and proline content of control plants declined. Drought stress significantly reduced SOD and APX activity, while NO treatment induced higher SOD and APX activity under drought conditions. After recovery, leaf RWC returned to the control level; however, NO‐sprayed plants showed higher RWC compared to controls. Both turfgrass species exhibited lower chlorophyll content at the recovery stage when exposed to severe drought stress, and NO application increased chlorophyll content compared to controls. No significant differences were found between NO treatment and control plants for proline and SOD activity, but APX activity of NO‐sprayed plants was higher than in the control plants. These results suggest that foliar application of NO may alleviate drought stress in turfgrass by maintaining membrane stability and inducing antioxidant enzyme activity.  相似文献   

4.
The grasses Lasiurus scindicus and Panicum turgidum are among the most important forage species of the Arabian deserts. Both are ‘glycophytic’ or salt‐intolerant species, where seed germination becomes reduced by salinity effects. Here, we report experimental effects of light/darkness, temperature and NaCl salinity on seed germination and ‘recovery’ germination in these two species, after seeds had been transferred from saline solution to distilled water. Seeds were germinated in a range of salinities and incubated at a range of temperatures, in both light and darkness. Seeds of P. turgidum germinated significantly more in darkness than in light at temperatures 15–25°C, but the reverse was true at higher temperatures. Seeds of L. scindicus germinated well across a wide range of temperatures and in both light and darkness. In both species, germination decreased with the increase in salt concentration, and in P. turgidum germination was almost completely inhibited at a concentration of 200 mm . In saline solution, germination in darkness was significantly greater than in light at all the temperatures. Seeds of both species ‘recovered’ their germination capacity after transfer from saline solutions to distilled water. Germination recovery depended on both light and temperature of incubation in both species.  相似文献   

5.
Water stress during the vegetative development normally is not detrimental and sometimes actually increases yield of peanut (Arachis hypogaea L.). Root growth might play an important role in response to early season drought in peanut and might result in an increase in yield. Information on the response of root characters of diverse peanut genotypes to these conditions will provide useful information for explaining mechanisms and improving peanut genotypes for exploiting positive interaction for pod yield under pre-flowering drought. The aim of this study, therefore, was to investigate the root dry weight and root length density of peanut genotypes with different yield responses to pre-flowering drought stress and their relationships with pod yield. Field experiments were conducted at the Field Crop Research Station of Khon Kaen University, Khon Kaen, Thailand during February to July 2007 and during February to July 2009. A split-plot experiment in a randomized complete block design was used. Two water management treatments were assigned as the main plots, i.e. field capacity and pre-flowering stress, and six peanut genotypes as the sub-plots. Total crop dry matter, root dry weight and root length density were recorded at 25 DAE, R5 and R7. Top dry weight and pod yield were measured at harvest and pod harvest index (PHI) was computed using the data on pod yield and biomass. Peanut genotypes were categorized into three groups based on their responses to drought for pod yield, e.g. increasing, decreasing and non-responsive groups. The genotypes of each group showed a differential response for root quantity and distribution. The increasing pod yield group had more root dry weight and root length density in the deeper soil layers during pre-flowering stress compared to the non-stress treatment. The non-responsive group showed no root response under pre-flowering drought conditions compared to the non-stress treatment. A larger root system alone without considering distribution may not contribute much to pod yield but a higher RLD at deeper layers may allow plants to mine more available water in the sub-soil. However, as yield is a complex trait, several mechanisms may be involved. The increasing pod yield group also had the ability to maintain a high PHI.  相似文献   

6.
为明确旱、盐及旱盐双重胁迫对花生根际土壤细菌群落的影响,本研究采用盆栽试验,通过16S rRNA基 因测序技术,研究了花生开花期干旱、盐胁迫及旱盐双重胁迫下花生根际土壤细菌群落结构的变化。结果表明,花 生根际土壤细菌群落均以放线菌纲(Actinobacteria)、α-变形菌纲(Alphaproteobacteria)、未分类菌目(norank_p__Sac⁃ charibacteria)、蓝藻纲(Cyanobacteria)、酸杆菌纲(Acidobacteria)、芽单胞菌纲(Gemmatimonadetes)和β-变形菌纲 (Betaproteobacteria)7个优势菌纲为主。干旱和盐胁迫处理均不同程度提高了α-变形菌纲和蓝藻纲的含量,且对蓝 藻纲的诱导效果较显著,推测蓝藻纲在提高花生胁迫耐受性方面具有重要功能。非生物胁迫影响根际土壤微域环 境,对花生根际土壤细菌群落结构具有调控作用。调节微生物群落结构,改良土壤微域环境,是提高植物胁迫耐受 性的有效途径。  相似文献   

7.
Summary A lysimeter experiment was performed to study the optimal allocation of limited water supply in potatoes. Irrigation regimes equal to 40, 60 and 80% of maximum evapotranspiration (ET) were evenly applied over the crop cycle. Other treatments involved withholding 80 mm of irrigation, based on ET, beginning at each of three designated growth stages (tuber initiation, early and late tuber growth). An irrigated control treatment, restoring the entire ET, was included for comparison. Continuous drought stress reduced photosynthesis as irrigation volumes were reduced. Plant biomass and tuber yield decreased almost proportionally to water consumption, so that WUE was roughly constant. N uptake was highest in the control and in 80% ET treatment. Withholding water during tuberisation severely hindered plant physiological processes and penalized tuber yield. Reductions in photosynthesis, total biomass and yield were the greatest when drought was imposed during tuber initiation. The earliest stress resulted in the lowest WUE and N uptake. A new crop water stress index (SI) was proposed, which combines atmospheric demand for water and canopy temperature.  相似文献   

8.
WRKY转录因子是近年来在植物中发现的一类重要转录因子,在植物抗逆相关过程中发挥重要作用。本研究通过对野生大豆转录组数据进行分析,从野生大豆中克隆得到GsWRKY57基因的CDS序列。该基因开放阅读框为903bp,编码300个氨基酸残基,分子量为34.23kD,等电点为5.88。氨基酸序列分析显示该蛋白含有一个WRKY保守结构域,属于III类WRKY转录因子。系统发育树分析表明该蛋白与栽培大豆同源性最高、其次是赤豆、木豆。启动子作用元件分析预测显示该基因可能存在多种非生物胁迫作用元件。组织特异性表达分析表明该基因在大豆叶片中高丰度表达,然后依次是茎、花、荚、根。GsWRKY57基因表达受茉莉酸、水杨酸、脱落酸、干旱等植物逆境诱导。过表达GsWRKY57基因的转基因拟南芥植株相对于野生型耐旱能力增强。  相似文献   

9.
Development of a standard evaluation protocol has been a pressing problem for the selection of drought‐resistant genotypes of tall fescue (Festuca arundinacea). This study was conducted to evaluate the association of forage yield with specific phenological and morphological traits to find a proper model for indirect selection under irrigated (normal) and drought‐stress conditions in tall fescue. A random sample of seventy‐five genotypes were clonally propagated and evaluated in normal and drought‐stress environments in the field during 2009 and 2010. Results showed that water stress had a negative effect on forage yield and most of the morphological traits measured and reduced genotypic variation for most of them. Forage yield had the highest genotypic variation, whereas days to pollination had the lowest variation. Low broad‐sense heritability estimates were obtained for dry‐matter yield, but heritability for the traits of number of stems per plant, plant height and crown diameter was moderately high. These traits were identified as the main components of forage yield. The importance of these components and their direct and indirect effects on forage yield was different in normal and drought‐stress conditions. This suggests that indirect selection for developing high‐yielding, drought‐tolerant varieties should be performed under drought‐stress conditions with a specific model.  相似文献   

10.
WRKY转录因子是近年来在植物中发现的一类重要转录因子,在植物抗逆相关过程中发挥重要作用。本研究通过对野生大豆转录组数据进行分析,从野生大豆中克隆得到GsWRKY57 基因的CDS序列。该基因开放阅 读框为903bp,编码300个氨基酸残基,分子量为34.23kD,等电点为5.88。氨基酸序列分析显示该蛋白含有一个 WRKY保守结构域,属于III类WRKY转录因子。系统发育树分析表明该蛋白与栽培大豆同源性最高、其次是赤豆、木豆。启动子作用元件分析预测显示该基因可能存在多种非生物胁迫作用元件。组织特异性表达分析表明该基因在大豆叶片中高丰度表达,然后依次是茎、花、荚、根。GsWRKY57 基因表达受茉莉酸、水杨酸、脱落酸、干旱等 植物逆境诱导。过表达GsWRKY57 基因的转基因拟南芥植株相对于野生型耐旱能力增强。  相似文献   

11.
为探讨不同花生品种低温胁迫下的萌发差异成因,为花生耐低温种植及抗冷性研究提供理论依据,本研究以耐低温品种豫花22号和中间耐性品种漯花16号以及低温敏感型品种泉花6号、鲁花11号为材料,测定不同温度处理条件下萌发相关的生理指标.结果显示,与CK相比,低温处理显著降低了各花生品种的露白率、发芽率、相对发芽率,不同抗性品种存...  相似文献   

12.
The effects of plant growth regulators (PGRs) and nitrogenous compounds on alleviating salinity stress on seed germination of Leymus chinensis in light (12 h light/12 h dark) and dark (24 h dark) conditions were determined in a laboratory experiment. Seed germination was compared at various combinations of salinity and germination‐promoting compounds. Seed germination percentages were 57 and 74% under non‐saline conditions in light and dark, respectively, suggesting that germination was light‐inhibited. Germination decreased significantly with increasing salinity level in both light and dark conditions, and the reduction was greater in light than in dark at each salinity level. Seed germination percentage decreased to 22 and 7% in light but only to 51 and 27% in dark, in 100 and 200 mm NaCl solutions respectively. The influence of PGRs and nitrogenous compounds in alleviating salinity stress varied with light and salinity condition; e.g., gibberellins (GA4 + 7) significantly increased germination percentages from 22%, 7% and 0·3% to 47%, 23% and 15% in light at 100, 200 and 300 mm NaCl, respectively, while they showed no effect on germination in darkness. In contrast, sodium nitroprusside and cytokinin significantly increased germination percentage in darkness at all salinity levels, but showed no effect on germination in light at 200 and 300 mm NaCl. Fluridone was very effective in alleviating salinity stress on germination in both light and dark; however, it was lethal to seedlings. Thiourea had no effect in alleviating salinity stress in either light or dark. Thus, alleviation of salinity stress on seed germination of L. chinensis by germination‐promoting compounds is strongly dependent on chemicals and light conditions.  相似文献   

13.
Leymus chinensis is a dominant and most promising grass species in the Songnen Grassland of Northern China. Experiments were conducted to determine the effect of temperature, salinity, alkalinity and their interactions on seed germination. Seeds were germinated at four alternating temperatures (10–20, 15–25, 20–30 and 25–35°C), with saline stress (9:1 molar ratio of NaCl:Na2SO4) and alkaline stress (9:1 molar ratio of Na2CO3:NaHCO3). Germination percentage and rate were inhibited by either an increase or decrease in temperature from the optimal temperature range of 20–30°C, and were also inhibited by an increase in salinity and alkalinity at all temperatures. The inhibitory effects of high salinity on germination were greater at 25–35°C, but seeds were subjected to more stress even though the alkalinity was low under this temperature. Recovery percentage was highest at 400 mm salinity at 20–30°C, but only at 100 mm alkalinity, and 25–35°C also resulted in lower recovery percentage under both stresses. Results suggest that saline stress and alkaline stress have different impacts on seed germination and that saline‐alkaline tolerance of L. chinensis seeds is affected by the interactions of temperature and salinity‐alkalinity. Early July sowing in the field is recommended when temperature is optimal and salinity‐alkalinity concentrations are reduced by the high rainfall.  相似文献   

14.
D. Levy 《Potato Research》1983,26(4):303-313
Summary The response of six potato cultivars, Désirée, Up-to-Date, Alpha, Elvira, Spunta and Troubadour, to water stress under high ambient temperatures was investigated. Osmotic regulation in the leaves of all six cultivars was highest in Alpha and the lowest in Troubadour. Concomitantly, Alpha maintained the highest turgor potential under water stress while Troubadour had the lowest values indicating a relationship between the degree of osmotic regulation and maintenance of turgor. The highest stomatal conductance under water stress was exhibited by Désirée while both stressed and non-stressed plants of Up-to-Date had the lowest values. In addition, Up-to-Date had a larger root system than Désirée. The association of these traits with tolerance to short periods of drought in the potato is discussed. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No 295-E, 1981 series. The investigation was supported in part by a grant from the Ministry for Development Cooperation of the Netherlands.  相似文献   

15.
Limited knowledge about the agronomic potential of Paspalum species from the Americas hinders their use in pastures. The response mechanisms to water deficit and waterlogging were studied in five accessions of Paspalum sp. (P. regnellii cv. BRS Guará and BGP 397, P. conspersum BGP 402 and P. malacophyllum BGP 289 and BGP 293) and Urochloa brizantha cv. Marandu. Morphological and physiological traits at the end of the stress and after the recovery period were measured. All Paspalum accessions, especially BGP 289, BGP 402 and BGP 397, and also cv. Marandu, showed survival mechanisms to water deficit. BRS Guará showed adaptive features to waterlogging, although had with a low survival rate to water deficit. Under waterlogging, BGP 289 and cv. Marandu showed reduced growth, and after the recovery period, they presented low plant survival and root recovery. Although growth of BGP 293 was reduced during waterlogging, it presented high tiller survival rate. BGP 293, BGP 402 and BGP 397 showed adaptive potential strategies for waterlogging and water deficit. There is genetic variability among the evaluated accessions for water deficit and waterlogging stresses, suggesting that they may be used per se or as progenitors in crosses with other genotypes in breeding programmes.  相似文献   

16.
This study aimed to investigate the possible causes for inconsistent performances of upland New Rice for Africa (NERICA) varieties in uplands and lowlands, while identifying important determinants in grain yield under deficient soil moisture. We compared the growth and yield of NERICA 1 and NERICA 5 to those of Yumenohatamochi, a Japanese upland variety, and Hinohikari, a Japanese lowland variety, subjected to different water management regimes (continually flooded, supplementary irrigation, and non-irrigation). Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased, whereas the panicle number of the Japanese varieties experienced little change. In contrast, the grain filling ratio was unaffected by water management, irrespective of variety. The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle, and water stress intensity was the primary factor for the degree of this reduction. Variation in the abortion of secondary rachis-branches caused differences between NERICAs in their spikelet number response to soil moisture deficiency. The inconsistency in NERICA performance across uplands vs. lowlands can be partially attributed to variation in yield response to low soil water conditions. Moreover, water stress intensity and the presence of a water gradient along the vertical soil profile may combine to affect the fluctuation in NERICA performance under upland conditions.  相似文献   

17.
用不同溶剂提取麻疯树根、茎、叶及种子的蛋白质,结果表明总蛋白以种子中含量最高,而营养器官中蛋白质主要集中在叶。萌发种子中蛋白质组分变化显著,而贮藏种子中蛋白质组分无太大变化。当年生种子、贮藏种子、茎和叶中所含蛋白质,以碱提组分含量最高;萌动种子和根中的蛋白质以水提组分含量最高。种子中抗癌蛋白质(28KD)、抗真菌蛋白质(22KD、21KD和20KD三亚基组成64KD)在碱提组分中含量最高。用30%PEG-6000处理麻疯树苗,发现在叶中诱导产生55KD、46KD、36KD、30KD、19KD、16KD和13KD多肽,在茎中产生33KD、30KD和23KD多肽,同时42KD和17KD多肽的含量减少。用4℃和51℃处理麻疯树苗,发现叶中54KD和24KD多肽在4℃和51℃均被诱导增加,44KD和36KD多肽在4℃和51℃均减少;茎中4℃和51℃诱导产生52KD、44KD和14KD多肽,诱导32KD、30KD和14KD多肽的增加。水分胁迫和温度胁迫在麻疯树根中未引起蛋白质组成的明显变化。  相似文献   

18.
Summary The slow kinetics of chlorophyll fluorescence were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Constant and variable fluorescence (F o andF v respectively) declined with time in plants from both irrigated and droughted treatments, but the decline was greater in droughted than irrigated plants. However, the yield of variable fluorescence (F v/(F o+F v)) was unaffected by the drought treatment. The main effect of drought was upon the quenching of variable fluorescence. Both the half life of the decay of variable fluorescence (q1/2) and the secondary maximum (M) were significantly greater in the droughted plants than in those from the irrigated treatment. Significant differences between genotypes were found forF v/(F o+F v),M andq 1/2. Genotype-by-treatment interactions were non-significant for all the variables examined. Changes in chlorophyll fluorescence transients were not closely related to changes in leaf water potential.  相似文献   

19.
Daily net canopy photosynthesis (Pn) of cocksfoot (Dactylis glomerata L.) was predicted for combinations of temperature, herbage nitrogen (N) concentration and water status from the integration of models of leaf photosynthesis of the light‐saturated photosynthetic rate (Pmax), photosynthetic efficiency (α) and the degree of curvature (θ) of leaf light‐response curves. The effect on Pn, maximum Pn (Pn max) and the optimum leaf area index (LAI at Pn max) was examined when any one of these factors was limiting. The ranges that gave the optimum values of Pn (Pn max = 30·8–33·5 g CO2m?2 d?1) for temperature (19–22°C) and N concentration (40–50 g N kg?1 DM) were smaller than those for net leaf photosynthesis. Also, Pn fell to 0 at a lower level of water stress (pre‐dawn leaf water potential, ψlp = ?12·5 bar) than for Pmax. The canopy photosynthesis model was then used to compare predicted and measured dry matter (DM) production for cocksfoot pastures grown under a diverse range of environmental conditions with field data from New Zealand and Argentina. To predict DM production leaf area index and leaf canopy angle were included from field measurements. The model explained about 0·85 of the variation in cocksfoot DM production for the range of 6·5–134 kg DM ha?1 d?1. The canopy model overestimated the DM production by 0·10 which indicates that a further Pmax function for leaves of different ages and a partitioning sub‐model may be needed to improve predictions of DM production.  相似文献   

20.
There is a growing interest in the use of deficit irrigation and perennial pasture species other than perennial ryegrass (Lolium perenne L.) in temperate agriculture, in response to the decreasing availability of irrigation water. Deficit irrigation requires an understanding of plant responses to drought stress to ensure maximum dry‐matter return on water applied. A glasshouse study was undertaken to investigate some of the morphological and physiological responses of perennial ryegrass, cocksfoot (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.; syn. Schedonorus phoenix Scop.) to varied moisture availability. One water treatment involved frequent applications of water to maintain a soil water potential of approximately ?10 kPa (100% treatment), and three other treatments involved applications at the same frequency, but using 33, 66 or 133% of the water applied in the 100% treatment. The water treatments continued over two plant regrowth cycles, followed by a ‘recovery’ phase of a single regrowth cycle during which all plants received the same water allocation as the 100% treatment. Depletion and replenishment of stubble water‐soluble carbohydrate (WSC) differed between the three species in response to soil moisture availability. By the second regrowth cycle, stubble WSC concentration and content in moisture‐stressed cocksfoot plants had increased, followed by a decrease during the subsequent recovery phase when the stored WSC reserves were utilized to support regrowth. The changes in stubble WSC reserves corresponded to the maintenance of relatively stable (i.e. the smallest reduction in leaf DM in response to moisture stress), but consistently lower DM production for cocksfoot compared with the other species. In contrast, moisture stress had no effect on the stubble WSC reserves of perennial ryegrass and tall fescue, with the exception of a significant decrease in WSC concentration under the 33% water treatment for perennial ryegrass. Perennial ryegrass achieved an intermediate DM yield and maintained positive growth rates throughout the study, even when watered at 33% of the requirement for optimal soil moisture levels. However, a more pronounced reduction in leaf DM in plants under moisture stress compared with the other species, combined with declining WSC reserves and the death of daughter tillers, highlighted the vulnerability of perennial ryegrass to poor persistence under prolonged drought conditions. Tall fescue appeared to have the greatest scope under moisture stress in terms of maintaining productivity and displaying attributes that contribute to persistence. Its leaf DM was consistently greater than that of the other species, displaying a smaller decline in growth under water stress compared to perennial ryegrass and an ability to recover faster upon re‐watering. This study has expanded the information available that compares and defines the potential of each species under moisture stress and emphasizes the importance of balancing short‐term DM production with long‐term persistence in choice of pasture species.  相似文献   

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