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1.
Temperature stress including low and high temperature adversely affect the growth, development and productivity of crops. Faba bean (Vicia faba L.) is an important crop as both human food source and animal feed, which contains a range of varieties that are sensitive to cold and heat stresses. In this study, 127 faba bean genotypes were collected from gene banks based on differences in geographical origin. The 127 genotypes were treated by single cold stress (2/2 °C day/night temperature (DT/NT)) and 42 genotypes were treated by either single episode of cold or heat (38/30 °C DT/NT) stress, or a combination of both at photosynthetic photon flux density of 250 µmol m?2 s?1. Chlorophyll fluorescence was used to detect the tolerance of faba beans to low and high temperatures. The maximum quantum efficiency of photosystem II (PSII), Fv/Fm, revealed pronounced differences in cold tolerance among the faba bean genotypes. The 42 genotypes were clustered into four groups according to cold and heat stresses, respectively, and the susceptibilities of faba beans under temperature stress could be distinguished. The combination of cold and heat stresses could aggravate the damage on reproductive organs, but not on the leaves, as indicated by the Fv/Fm. These results confirm that the use of Fv/Fm is a useful approach for detecting low and high temperature damage to photosystem II and to identify tolerant faba bean genotypes, however the results also indicate that the geographical origin of the genotypes could not directly be used to predict climate resilience. These sources of cold- and heat-tolerance could improve the temperature tolerance of faba bean in breeding programs.  相似文献   

2.
The expected temperature rise in late summer/early autumn can change the conditions for acclimation and affect the winter survival of perennial crops. This study examined the effect of the temperature just before the onset of cold acclimation (pre‐acclimation) on freezing tolerance of timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) populations (both cultivars and breeding populations) adapted to either northern or southern parts of Norway. Using phytotron experiments, we studied whether increasing pre‐acclimation temperature delays growth cessation, affects photoacclimation and reduces freezing tolerance. Furthermore, we assessed whether these effects were related to the latitudinal adaptation of the plant material. The results showed that a rise in pre‐acclimation temperature decreased both cold acclimation capacity and photoacclimation in these species. This affected the freezing tolerance, which was reduced significantly more in northern‐adapted population of timothy and perennial ryegrass compared with southern‐adapted populations. Red clover was less affected by temperature changes than the grasses.  相似文献   

3.
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4.
Experiments were conducted over 2 years to quantify the response of faba bean (Vicia faba L.) to heat stress. Potted winter faba bean plants (cv. Wizard) were exposed to temperature treatments (18/10; 22/14; 26/18; 30/22; 34/26 °C day/night) for 5 days during floral development and anthesis. Developmental stages of all flowers were scored prior to stress, plants were grown in exclusion from insect pollinators to prevent pollen movement between flowers, and yield was harvested at an individual pod scale, enabling effects of heat stress to be investigated at a high resolution. Susceptibility to stress differed between floral stages; flowers were most affected during initial green‐bud stages. Yield and pollen germination of flowers present before stress showed threshold relationships to stress, with lethal temperatures (t50) ?28 °C and ~32 °C, while whole plant yield showed a linear negative relationship to stress with high plasticity in yield allocation, such that yield lost at lower nodes was partially compensated at higher nodal positions. Faba bean has many beneficial attributes for sustainable modern cropping systems but these results suggest that yield will be limited by projected climate change, necessitating the development of heat tolerant cultivars, or improved resilience by other mechanisms such as earlier flowering times.  相似文献   

5.
Freezing tolerance of 60 breeding lines of winter hexaploid triticale (×Triticosecale Wittmack) was studied in the field‐laboratory experiment. The experiment was repeated over three winters. The survey was also carried out in plants grown and cold‐acclimated in the laboratory. In both the experiments, plant survival analysis and chlorophyll fluorescence‐based studies on energy flows in photosystem II (PSII) (JIP‐test) after freezing of detached leaves were performed. In the laboratory experiment, the temperature of 50 % electrolyte leakage from leaves and the resistance against cold‐induced photoinhibition were additionally investigated. In the case of plants’ cold‐acclimated in the field, determination of the freezing tolerance of PSII gave similar results as the determination of freezing tolerance of whole plants. Both traits were strongly affected by genotype–environmental interactions, but these effects were less visible for PSII characteristics. In the laboratory experiments, a strong correlation between freezing tolerance and the tolerance for cold‐induced photoinhibition of photosynthesis was observed. The possibility of the use of chlorophyll fluorescence‐based techniques for the determination of freezing tolerance in triticale is discussed.  相似文献   

6.
Winter conditions are subjected to rapid climate changes. Increased precipitation and snow melting during warmer winters may result in low‐temperature flooding. These factors probably affect plant overwintering strategies. This study investigated the relationships between the photosynthetic adjustment and freezing tolerance following a short‐term low‐temperature flooding in two forage grasses (Lolium perenne and Festuca pratensis). The effect of flooding on the photosynthetic apparatus acclimation to cold was determined using chlorophyll a fluorescence measurements. Freezing tolerance was estimated using an electrolyte leakage test. It has been shown that genotypes activating non‐photochemical mechanisms of photosynthetic acclimation to cold during low‐temperature flooding may show increased freezing tolerance. Freezing tolerance reduction observed in Festuca pratensis was probably connected with decreased photochemical activity and photoinhibition of photosynthesis. It can be concluded that photosynthetic apparatus response to low‐temperature flooding may contribute to changes in the freezing tolerance. The direction of the changes is associated with different photosynthetic apparatus performance.  相似文献   

7.
The aim of this study was to reduce the length of the breeding cycle for faba bean by accelerating seed setting. We examined the mode and time of exogenous 6-benzylaminopurine (BAP) (cytokinin) application, and cold treatments and their combinations in two faba bean genotypes. Acropetal node number of pod and seed set and pollen viability were recorded during the experiments. Application of BAP improved pollen germination. The application of 10–5 M BAP 4 days after flowering increased seed set at the lower nodes. Cold treatment (8/4°C day/night for 2 days) after the onset of flowering induced the formation of more pods and faster pod set compared to the non-cold treatment. The time to first seed was significantly reduced, and pollen viability was increased in plants exposed to cold treatment. Increased pollen viability also showed a significant positive correlation with seed setting. The combinations of 10–5 BAP and cold treatment together had similar and independent effects. These results will accelerate plant breeding in faba bean by providing additional tools for reducing generation time.  相似文献   

8.
Winter‐hardiness is a complex trait limiting cultivation of winter barley (Hordeum vulgare ssp. vulgare) with respect to the regions of temperate climate. In the present studies, we verified whether inexpensive and fast physiological markers characterizing photosynthetic acclimation to cold may provide robust characteristics of winter barley genotypes for improved frost resistance. Freezing tolerance of 28 winter barley varieties and advanced breeding lines were tested for three winters in field‐laboratory experiment and under fully controlled conditions. To increase the environmental variability of freezing tolerance, a part of the plants were also de‐acclimated under semi‐controlled conditions and re‐acclimated in laboratory before freezing tests. After controlled cold acclimation, apparent quantum yield of photosystem II (Fv/Fm) as well as photochemical (qP) and non‐photochemical (NPQ) coefficients of chlorophyll fluorescence quenching were studied. Field‐laboratory method assessment of freezing tolerance gives distinct and even opposite results in subsequent years. Also de‐acclimation interacted with growth conditions in the field, giving different rankings of genotypes each year. The results obtained suggest that high level of freezing tolerance measured in laboratory, which is connected with photosynthetic acclimation to cold may be not sufficient for the expression of field resistance, especially when winter conditions are not favourable for cold acclimation.  相似文献   

9.
Increasing productivity through improvement of photosynthesis in faba bean breeding programmes requires understanding of the genetic control of photosynthesis‐related traits. Hence, we investigated the gene action of leaf area, gas exchange traits, canopy temperature, chlorophyll content, chlorophyll fluorescence parameters and biomass. We chose inbred lines derived from cultivars 'Aurora' (Sweden) and 'Mélodie' (France) along with an Andean accession, ILB 938, crossed them (Aurora/2 × Mélodie/2, ILB 938/2 × Aurora/2 and Mélodie/2 × ILB 938/2), and prepared the six standard generations for quantitative analysis (P1, P2, F1, F2, B1, and B2). Gene action was complex for each trait, involving additive and dominance gene actions and interactions. Additive gene action was important for SPAD, photosynthetic rate, stomatal conductance and Fv/Fm. Dominance effect was important for biomass production. It is suggested that breeders selecting for productivity can maximize genetic gain by selecting early generations for canopy temperature, SPAD and Fv/Fm, then later generations for biomass. The information on genetics of various contributing traits of photosynthesis will assist plant breeders in choosing an appropriate breeding strategy for enhancing productivity in faba bean.  相似文献   

10.
J.U. Chun  X.M. Yu  M. Griffith 《Euphytica》1998,102(2):219-226
Antifreeze proteins (AFPs) accumulate in the leaves of winter cereals during cold acclimation, where they may inhibit ice recrystallization during freezing and thawing cycles and provide nonspecific disease resistance. In this study, 21 wheat chromosome substitution lines and the parental lines Chinese Spring and Cheyenne wheat were used to determine the heritability of AFPs and the relationship between the accumulation of AFPs and winter survival. In cold-acclimated lines, antifreeze activity in leaf apoplastic extracts ranged from 1 (low) to 5 (high) with an average value of 3.2, and the accumulation of apoplastic proteins ranged from 30 μg (g FW)-1 to 115 μg (g FW)-1 with a mean value of 70 μ (g FW)-1. Examination of the individual lines revealed that Cheyenne chromosomes 5B and 5D carry major regulatory genes that increase both antifreeze activity and the accumulation of antifreeze proteins in plants grown at low temperature. Substitution lines carrying Cheyenne chromosomes 2A, 3A, 6B, and 7A exhibited lower freezing tolerance and also showed a marked decrease in the accumulation of specific AFPs during cold acclimation. Antifreeze activity and apoplastic protein content were not correlated with freezing tolerance (defined as % survival at -11 °C), but they were both significantly and positively correlated with winter field survival rates. Antifreeze activity (positively correlated) and total leaf fresh weight (negatively correlated) together accounted for about 55% of the variation in winter survival, indicating that high antifreeze activity and slow vegetative growth at low temperature are both important quantitative traits for winter survival. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

11.
The aims of the study were to determine why young Miscanthus × giganteus plants are more frost sensitive during the first winter than older plants, to compare cold tolerance of plants propagated in in vivo and in vitro conditions, and to select plants with higher cold tolerance. The study was performed in three experiments in which plants were prehardened at 12 °C for 2 weeks, hardened at 5 °C for 3 weeks and next chilled at 0 °C or ?3 °C for 3 or 14 days. Afterwards shoot regrowth from rhizomes was evaluated. In Experiment 1 frost tolerance of young plants obtained from a horticultural farm and plants that had already survived the first winter in the field was compared on the basis of LT50 coefficient. In Experiment 2 frost tolerance of plants obtained in vivo and in vitro was compared. Experiment 3 was performed on four groups of plants: in vivo and in vitro obtained plants which were twice selected in cold, as well as in vivo and in vitro obtained plants which were cold treated once. Plants of all these groups were analysed with respect to their frost tolerance. They were prehardened, hardened and subjected to a temperature of 0 °C or ?3 °C for 14 days. The changes in processes accompanying cold acclimation occurring in the rhizomes or leaves of these plants were investigated. The content of abscisic acid, low-molecular antioxidants and phenolics, as well as catalase and non-specific peroxidase activities were analysed.Young commercially obtained plants were more frost sensitive than plants which had survived the first winter in the field. This effect could be caused by a small amount of storage compounds accumulated in finely divided rhizomes produced in a horticultural farm. Prehardening temperature of 12 °C caused more considerable changes in cold acclimation processes in Miscanthus rhizomes than hardening temperature of 5 °C. Plants propagated by in vitro culture were more cold tolerant but only in the first vegetative season compared to plants obtained in vivo. Plants chilled twice demonstrated a higher low-molecular antioxidant level, as well as a greater capability of phenolic accumulation compared to plants which were once cold stressed. Regardless of the recurrence of cold acclimation, ABA level was significantly increased in leaves by prehardening and in rhizomes by hardening. Each repetition of cold acclimation increased cold tolerance and shoot regeneration ability of M. × giganteus rhizomes.  相似文献   

12.
Genetic mapping for faba bean lags far behind other major crops. Density enhancement of the faba bean genetic linkage map was carried out by screening 5,325 genomic SSR primers and 2033 expressed sequence tag (EST)‐SSR primers on the parental cultivars '91825' and 'K1563'. Two hundred and fifteen genomic SSR and 133 EST‐SSR primer pairs that detected polymorphisms in the parents were used to screen 129 F2 individuals. This study added 337 more SSR markers and extended the previous linkage map by 2928.45 cM to a total of 4516.75 cM. The number of SSR markers in the linkage groups varied from 12 to 136 while the length of each linkage group ranged from 129.35 to 1180.21 cM. The average distance between adjacent loci in the enhanced genetic linkage map was 9.71 cM, which is 2.79 cM shorter than the first linkage map of faba bean. The density‐enhanced genetic map of faba bean will be useful for marker‐assisted selection and breeding in this important legume crop.  相似文献   

13.
Like most plants, pea (Pisum sativum L.) becomes tolerant to frost if it is first exposed to low non-freezing temperatures, a process known as cold acclimation. Cold acclimation is a complex process involving many physiological and metabolic changes. Two spring dry peas, two winter dry peas and one winter forage line were exposed to cold temperature in a controlled environment in two experiments, one using low light intensity and the other regular light intensity. Plants were harvested throughout the experiment and dry matter accumulation, water content, soluble and insoluble sugar concentrations were determined from shoot and root samples. Cold acclimation did not occur when temperatures were low if light intensity was low, even in winter peas. In contrast, with regular light intensity, the winter peas acquired more freezing tolerance than spring peas and a close relationship was found between the soluble sugar concentration of leaves just before the frost and the degree of freezing tolerance obtained by the different genotypes. Relationships between freezing tolerance and carbon partitioning between shoot and roots are discussed.  相似文献   

14.
The effect of 0, 0.05 or 0.1 mm abscisic acid treatment on chilling tolerance and salicylic acid‐related responses was investigated in young maize seedlings (Zea mays L., hybrid Norma). Although the pre‐treatment of maize seedlings with abscisic acid slightly decreased the chlorophyll content, it also reduced the level of chilling injury caused by 6 days of cold treatment at 5 °C. Under normal growth conditions, increased levels of bound salicylic acid and of bound ortho‐hydroxycinnamic acid were observed in the leaves during abscisic acid treatment. In the roots, abscisic acid did not affect the free and bound salicylic acid levels, but increased the amount of free and bound ortho‐hydroxycinnamic acid. The activity of glutathione‐S‐transferase increased on the 3rd day of abscisic acid treatment, whereas it did not change when followed by cold stress, compared with the control leaves. In the roots, the activities of glutathione reductase, glutathione‐S‐transferase and ascorbate peroxidase increased during the abscisic acid treatment, and those of glutathione‐S‐transferase and ascorbate peroxidase were also stimulated when abscisic acid pre‐treatment was followed by cold stress, compared with the control roots. Our results suggest that an overlap may exist between the abscisic acid‐induced cold acclimation and the salicylic acid‐related stress response.  相似文献   

15.
In rice, pre‐exposure to sublethal treatment followed by harsh lethal treatment is known to improve tolerance of different abiotic stresses at the vegetative stage within and across generations. Our major aim was to test the phenomenon of thermo‐tolerance at flowering across (trans)‐generations and within generation using rice cultivars contrasting for heat stress tolerance at flowering. To test trans‐generational response, plants were exposed to higher temperature at flowering stage and seeds obtained from previous generations were exposed to heat stress during flowering, which recorded significantly lower fertility when exposed to the same degree of stress in their subsequent generations. A pre‐acclimation to moderately high acclimating temperatures imposed over three different durations during the vegetative and initial reproductive stage showed positive response in the tolerant N22, particularly under severe heat stress (40 °C). This finding indicates the possibility of acquiring ameliorative thermo‐tolerant mechanisms at anthesis, restricted to tolerant genetic backgrounds to combat subsequent harsh conditions within the same generation. However, trans‐generational memory was ineffective in mitigating spikelet sterility losses in both tolerant and susceptible backgrounds. Rice is extremely sensitive to heat stress during flowering; hence, similar exercise across other crops of interest needs to be carried out before generalizing conclusions.  相似文献   

16.
Predicting and understanding the progress towards flowering in faba bean are important to achieve the adaptation and high productivity of the crop under varying environmental conditions. Traditional controlled‐environment experiments showed that the rate of progress towards flowering was dependent mainly on photoperiod and temperature. Here, we highlight the need to include measures of solar radiation and water deficit in order to achieve an adequate model for field conditions. The improved model was assessed in two steps: first with a “basic” model across all 20 cultivars and then with an “extended” model that included terms to fit exceptional cultivars. The two new parameters were necessary to achieve an acceptable fit of progress towards flowering and clearly separated two cultivars, “Kontu” and “Witkiem Manita,” that were significantly quicker to flower than the other 18, which fit a single line. As the regression coefficients of the two exceptional cultivars differed only in intercept, not slope, we conclude that flowering responses to day length, temperature, solar radiation and drought stresses were consistent in this set of germplasm and that the two cultivars differed in earliness “per se.” Growth‐chamber experiments added information about differing ceiling temperatures for progress to flowering in four cultivars and different sensitivities to supraoptimal temperatures.  相似文献   

17.
Precipitation has generally increased in Norway during the last century, and climate projections indicate a further increase. The growing season has also become longer with higher temperatures, particularly in autumn. Previous studies have shown negative effects of high temperatures and, depending upon temperature conditions, contrasting effects of waterlogging on hardening capacity of timothy. We studied effects of waterlogging on seedlings of timothy (Phleum pratense, cv. Noreng) under three pre-acclimation temperatures: 3°C, 7°C, 12°C, and in autumn natural light in a phytotron at Holt, Tromsø (69°N). After temperature treatments, all plants were cold acclimated at 2°C for three weeks under continued waterlogging treatments. Freezing tolerance was determined by intact plants being frozen in pots at incremental temperature decreases in a programmable freezer. Waterlogging resulted in a higher probability of death after freezing, and a significantly reduced regrowth after three weeks at 18°C, 24 hrs light in a greenhouse. Increasing pre-acclimation temperatures also had a clear negative effect on freezing tolerance, but there was no interaction between temperatures and waterlogging. The results indicate that waterlogging may have negative implications for hardening of timothy and may contribute to reduced winter survival under the projected increase in autumn temperatures and precipitation.  相似文献   

18.
Winter‐grown canola (Brassica napus L.) production is limited mostly by frost and winter kill in the southern canola‐growing regions of the United States. Tolerance to cold and heat were assessed by studying percentage of pollen viability (PV), in vitro pollen germination (PG) and pollen tube length (PTL) for 12 field‐grown cultivars. Freshly collected pollen from all cultivars were incubated on artificial solid growth media at a constant temperature ranging from 10 to 35 °C at 5 °C interval for 30 h to determine PG and PTL. A modified bilinear model best described the temperature response functions of PG and PTL. Canola cultivars showed significant variability (P < 0.001) for PV (61.3 % to 89.7 %), PG (29.0 % to 48.2 %) and PTL (463 to 931 μm). The average cardinal temperatures, Tmin, Topt and Tmax, for PG and PTL were 6.4, 24.3 and 33.7 °C, respectively. Principal component analysis revealed that maximum PG, PTL, Tmin and Topt of both PG and PTL were the most important factors in determining cold tolerance, whereas Tmax of PG and PTL, and maximum PG and PTL were more responsible in separating the cultivars for heat tolerance. The canola cultivar, KS3077, was the most cold tolerant with the lowest Tmin and the widest temperature adaptability range, and the cultivar Kadore was the most heat tolerant with the highest Tmax for the PG. The identified cold‐ and heat‐tolerant cultivars may be useful in canola‐breeding programmes to develop cultivars suitable for a niche environment.  相似文献   

19.
A Rapid Method for Measuring Freezing Resistance in Crop Plants   总被引：3，自引：0，他引：3  
The objective of this study was to develop a technique based on chlorophyll fluorescence to assess freezing injury and resistance of leaves. Optimization was done with faba bean leaves and applicability to other crops was examined at winter and spring with types of barley, oats, rape and faba beans. Selected leaves from young hardened beans were subjected to standardized freezing tests with different minimum temperatures ( T min) and fluorescence was monitored. After a dark period basic fluorescence ( F O was induced by 0.2 μmol m−2 s−1 pulsed red light and maximum fluorescence ( F m) was assayed at different light intensities. 1500 μmol m−2 s−1 rendered to give the maximum possible output of Fm and best differentiation of differently damaged leaves by F n= F m - F O. Leaf temperature during measurement and during a short storage (± 2 h) should be kept at about 0°C to avoid biases between differently damaged leaves. The measuring spot on the leaf must be standardized since fluorescence response differed at the tip and base of a leaflet, but not between the two leaflets of a faba bean leaf. The applicability of F rr (ratio of F r of stressed to unstressed leaves) as a measure of resistance was demonstrated by comparison of winter hardiness of cultivars with freezing resistance calculated from the relationship of F vr and the T min used in freezing tests.  相似文献   

20.
The adaptation of St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze) in the transitional climatic zone of the United States is limited due to a lack of sufficient freeze tolerance. Lab-based freeze testing provides plant breeders with a reliable method for evaluating freeze tolerance. However, in developing protocols for freeze testing it is important to account for the underlying mechanisms that affect freeze tolerance. The objective of this research was to evaluate the effects of cold acclimation and deacclimation on nine St. Augustinegrass genotypes ranging in their levels of freeze tolerance. Results indicated that accounting for all levels of acclimation provided excellent genotype separation across freezing temperatures (? 3 and ? 4 °C) and supports the hypothesis that the inclusion of acclimation response offers the best overall assessment of freeze tolerance. Genotypes with the highest known field winter survival had also the highest improved freeze tolerance upon cold-acclimation. Other genotypes did not respond to cold-acclimation which resulted in poor survival and recovery rates. Conversely, a significant loss of freeze tolerance was identified when plants were subjected to deacclimation events suggesting that St. Augustinegrass can be negatively affected by rapid temperature changes in the transitional climatic zone leading to increased sensitivity to winterkill. Overall, this study provides preliminary information regarding the complex relationships within and between mechanisms affecting freeze tolerance in St. Augustinegrass. Moreover, results presented here should aid in the development of protocols for selection of freeze tolerant breeding materials under controlled environmental conditions.  相似文献   

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