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1.
The degree of salt tolerance of two newly developed genotypes of spring wheat, S24 and S36 was assessed with respect to their parents, LU26S (from Pakistan) and Kharchia (from India). These four lines along with a salt-tolerant genotype SARC-1 and two salt-sensitive cvs Potohar and Yecora Rojo were subjected to salinized sand culture containing 0, 125 or 250 mol m?3 NaCl in full strength Hoagland's nutrient solution. S24 produced significantly greater grain yield and had greater 1000 seed weight and number of tillers per plant than those of the other cultivars /lines. S36 was not significantly different from its parents in seed yield and yield components. SARC-1 was the second highest in grain yield of all cultivars/lines, but it did not differ significantly from LU26S and Kharchia in 1000 seed weight and number of tillers per plant. The greater degree of salt tolerance of S24 could be related to its lower accumulation of Na+ in the leaves and maintenance of higher leaf K/Na ratios and K versus Na selectivity as compared to its parents. S36, which was as good as its parents in growth, also had lower Na+ and higher K/Na ratios and K versus Na selectivity in the leaves at the highest salt level than those in its parents. SARC-1 did not differ from LU26S and Kharchia in ionic content or K/Na ratios and K versus Na selectivities of both leaves and roots. Both the salt-sensitive cultivars, Potohar and Yecora Rojo, had significantly greater leaf Na+ and Cl? concentrations and lower leaf K/Na ratios and K versus Na selectivities than all the salt-tolerant lines examined in this study. From this study it is evident that improvement in salt tolerance of spring wheat is possible through selection and breeding, and pattern of ion accumulation is not consistent among the salt-tolerant genotypes in relation to their degree of salt tolerance.  相似文献   

2.
Thirty-six accessions of linseed ( Linum usitatissimum L.) were screened for salt tolerance at the seedling stage after 2 weeks growth in solution culture salinized with 150mol m−3 NaCL Considerable variation in salt tolerance was observed in this set of germplasm. Two salt-tolerant accessions, T-5(69-S9)B and LS-2 and two salt-sensitive accessions P-70 and Aver-Rer-Seic, selected at the seedling stage, were grown to maturity in sand culture salinized with 0 (control), 70, 140, and 210 mol m−3 NaCl. Both the salt-tolerant accessions exceeded the two salt-sensitive accessions in biomass production, seed yield, and yield components, but the accessions did not differ significantly in seed oil content in the salt treatments. The tolerant accessions accumulated greater amounts of Na+ in the shoots and less in the roots compared with the salt-sensitive accessions. The shoot K+, K: Na ratios, and K+ versus Na+ selectivity were lower in the salt-tolerant accessions compared with the salt-sensitive accessions; the reverse was true for their roots. Contributions of Na+ and Ca2+ to osmotic adjustment were much higher in the two salt-tolerant accessions than in the salt-sensitive ones.
It has been established that there is a great deal of variation for salt tolerance in linseed. The degree of salt tolerance of this crop does not vary during ontogeny. The physiological basis of salt tolerance of this species appears to be associated with the inclusion of Na+ in the shoots.  相似文献   

3.
The salt tolerance of two salt-tolerant (C90-1191 and P5/80) and two salt-sensitive (C90-1115 and 77–321) lines of Ethiopian mustard ( Brassica carinata ) (selected on the basis of their performance in germinating ability and seedling growth in a screening experiment) was assessed at the adult stage under glasshouse conditions to evaluate the consistency of salt tolerance at different growth stages of plant life cycle. No difference in response of all four lines differing in salt tolerance was found to varying concentrations of NaCl in the growth medium, although the latter two lines were slightly better than the former two in shoot dry mass, seed yield or yield components. The relatively good growth of the lines C90-1115 and 77-321 at the adult stage can be related to their lower accumulation of Na, Cl and Ca in their leaves. K/Na ratios, Ca/Na ratios, K versus Na selectivity, and Ca versus Na selectivity did not prove to be successful criteria in discriminating the lines differing in degree of salt tolerance. In conclusion, salt tolerance in B. carinata varies with the change in stage of its life cycle. Thus selection based at one particular stage may not produce individuals tolerant at all growth stages.  相似文献   

4.
Seedling growth and ion content of Pakistani bread wheat cultivars was assessed in solution culture in the absence and presence of NaCl (100 and 200 mol m−3) to determine whether seedling traits could be used in breeding programs for salt-tolerance. Growth was recorded as seedling fresh weight, and the shoot and leaves analysed for major inorganic ions. Plants subjected to salt stress excluded Na+ and Cl ions from the shoot to varying extents. Exclusion preferentially maintained lower Na+ and Cl levels in the apical tissue, as the leaf to leaf gradient in Na+ and Cl became steeper as the external salinity increased, although there were significant differences between cultivars. Correlation analysis on individual plants indicated that excluding Na+ at low salinity, and Na+ and Cl at high salinity, were correlated significantly with growth performance, although it was clear that other factors were also involved. The relationship of tolerance to ion exclusion was stronger when the data were examined on an individual plant basis than when related to pooled cultivar data or to the cultivar rank order derived from field trials, probably due to large variations in Na+, and to a lesser extent, Cl transport in supposedly homozygous cultivars.  相似文献   

5.
Experiments conducted m a phytotron on three rice varieties of different salinity tolerance revealed an increase in the content of endogenous abscisic acid (ABA) with increasing NaCl salinity in IR20 (semi salt-tolerant), but in Pokkali (salt-tolerant) and IR28 (salt-sensitive) the increase in ABA content was marginal. Under sahnity stress, in general, 5 weekly sprayings of ABA (10-4 mol L-1) decreased Na and K concentrations in the shoot to the extent of 29.5 % and 3.3 %, respectively. However, ABA application significantly improved the K/Na ratio as well as the chlorophyll fluorescence decrease ratio (Rfd, indicator for potential photosynthetic activity), the number of green leaves per plant and the shoot dry weight. The response of IR20 and IR28 to ABA application was significantly better than that of Pokkali. Increasing salinity caused marked nutrient imbalances, decreased Rfd values and shoot dry weight. The results are discussed in relation to possible mechanism of salinity tolerance.  相似文献   

6.
Long days at high latitudes inhibit tillering of cereals and hence seeding rates of 500–700 seeds m−2 are commonly used for spring wheat, barley and oats in Finland. Costs could be reduced by using a lower seeding rate in combination with crop management to produce more head-bearing tillers m−2. This study was designed to assess possibilities of breaking the uniculm growth habit of spring cereals by (1) lowering the seeding rate from 600 to 300 seeds m−2 and (2) manipulating tiller growth with early mechanical treatments to the crop (rolling, cutting) or chemical applications (foliar urea, CCC and GA). A low seeding rate and early application of foliar CCC at high latitudes, under good moisture conditions prior to heading, promoted 20% more head-bearing tillers and 6% higher grain yield than standard management practices. However, cultivars differed in their response to CCC. The advantageous effects of CCC at a low seeding rate were attributed to increase, over the controls, in contribution of head-bearing tillers to grain yield in wheat (cultivar Heta ), but more grains per head in oats (cultivar Veli ). Varietal recommendations for use of low seeding rate in combination with early CCC spraying should be examined further.  相似文献   

7.
Four bread wheat cultivars were studied at two salinity levels. Tobari 66 had the lowest uptake of Na+ and Cl, and the highest K+/Na+ ratio; Pato had the highest uptake of these ions and Lyallpur 73 was intermediate. Intervarietal differences were greater at higher salinity, suggesting that they were not caused by variation at the Kna1 locus. There were significant differences between inbred lines for Na+, particularly in Blue Silver, suggesting the possibility of selecting genotypes with enhanced tolerance from within existing cultivars. Pato, Tobari 66 and their reciprocal F1 hybrids were further evaluated at four salinity levels. The hybrids exhibited similar relative grain yield to Tobari, with better Na+ and Cl exclusion and higher K+/Na+ ratios than Pato. Overall, Tobari had the highest absolute yield under salinity, and the hybrids were closer to Tobari than to Pato. Tiller and grain numbers, 100-grain weight and yield were more affected by salinity than were height, spike length and spikelet number. We conclude that intervarietal variation for salt tolerance in wheat is controlled by genes which could be transferred to sensitive genotypes to improve their tolerance, and that the K+/Na+ ratio of the youngest leaf could be used to screen for salt tolerance.  相似文献   

8.
The effect of salinity on the nodulation, N-fixation and plant growth of selected chickpea- Rhizobium symbionts was studied- Eighteen chickpea rhizobial strains were evaluated for their growth in a broth culture at salinity levels of 0 to 20 dS m−1 of NaCl + Na2SO4. Variability in response was high. Salinity generally reduced the lag phase and/or slowed the log phase of multiplication of Rhizobium. Nine chickpea genotypes were also evaluated for salt tolerance during germination and early seedling growth in Petri dishes at five salinity levels (0–32 dS m−1). Chickpea genotypes ILC-205 and ILC-1919 were the most salt-tolerant genotypes. The selected rhizobial strains and chickpea cultivars were combined in a pot experiment aimed at investigating the interactive effect of salinity (3, 6 and 9 dS m−1) and N source (symbiosis vs. inorganic N) on plant growth. Symbiotic plants were more sensitive to salinity than plants fed mineral N. Significant reductions in nodule dry weight (59.8 %) and N fixation (63.5 %) were evident even at the lowest salinity level of 3 dS m-1. Although nodules were observed in inoculated plants grown at 6 dS m-1, N-fixation was completely inhibited. The findings indicate that symbiosis is more salt-sensitive than both Rhizobium and the host plant, probably due to a breakdown in one of the processes involved in symbiotic-N fixation. Improvement of salinity tolerance in field grown chickpea may be achieved by application of sufficient amounts of mineral nitrogen.  相似文献   

9.
为研究不同追氮时期追氮比例对滴灌冬小麦的生长发育及产量的影响,在滴灌条件下,以小麦‘新冬18号’为试验材料,在总施氮量300 kg/hm2条件下,设置5个氮肥追施处理[拔节:孕穗6:4(F1处理)、起身:拔节:开花2:4:4(F2处理)、拔节:孕穗:开花4:4:2(F3处理)、起身:拔节:孕穗:开花2:4:2:2(F4处理)、起身:拔节:孕穗:开花2:2:2:4(F5处理)],研究不同处理对滴灌冬小麦生长特性及产量的影响。结果表明,适当调节氮肥追施时期及比例有利于调节小麦的生长及产量,F4处理能减缓叶片SPAD值的下降速度,还能有效提高小麦千粒重、收获指数、地上部分生物总量,最高产量为F4处理,产量达8016.67 kg/hm2,分别显著高于F1、F2处理6.4%和6.7%(P<0.05)。在本试验条件下,氮肥追施时期以起身、拔节、孕穗、开花期均追肥(F4、F5处理)有利于小麦的生长与产量的提高。  相似文献   

10.
宁夏青铜峡灌区管道自流引水畦灌初探   总被引:1,自引:1,他引:0  
为了探讨管道自流引水畦灌的应用前景,以宁夏青铜峡灌区典型春小麦农田为研究对象,采用管道自流引水畦灌,研究不同畦田规格(2 m×50 m、3 m×50 m、3 m×30 m、5 m×30 m)对灌水质量和作物水分利用效率的影响,并讨论了该条件下当地春小麦耗水规律。结果表明:春小麦整个生育期内,采用管道自流引水畦灌方式,在分蘖至拔节期中、拔节至孕穗期中、抽穗至开花期末进行灌水量分别为667 m3/hm2、1500 m3/hm2、900 m3/hm2的灌溉,可满足当地春小麦生产需要。而且,在这种畦灌方式条件下,入畦流量虽然只有160 L/min左右,但小块畦田(3 m×30 m、2 m×50 m)依然能够获得较高的灌水均匀度(88.1%、85.5%)和灌水效率(90.5%、86.8%),进而获得较高的产量(5149.3 kg/hm2、5085.5 kg/hm2)和水分利用效率(1.07 kg/(mm·hm2)、1.05 kg/(mm·hm2))。从田间试验角度论证了管道自流引水畦灌能实际应有于合适地区。  相似文献   

11.
Interactive effect of NaCl salinity and putrescine on shoot growth, ion (Na+, K+ and CI) concentration in leaf, stem and inflorescence and yield of rice (Oryza sativa L. var. GR-3) were studied. When rice plants were subjected to salt stress (12 dS/m) the extension growth and dry weight of shoot system as well as total leaf area and chlorophyll content were found markedly reduced. Analysis of leaf, stem and inflorescence of salt-stressed plants showed higher concentration of Na+ and Cl ions and lower concentration of K+ ion compared to the control. Salinization also caused a considerable fall in grain yield.
Foliar application of putrescine (10−5M) significantly increased the growth and yield of salt-stressed plants. Putrescine treatment decreased the influx of Na+ and Cl ions and increased the K+ level in all the tissues of salinized plants examined. Putrescine also increased the chlorophyll content in salt-stressed plants. These results suggest that exogenous application of putrescine can be used successfully to ameliorate the stress injuries caused by NaCl salinity in rice plants to a considerable extent.  相似文献   

12.
甘薯苗期耐盐性鉴定及其指标筛选   总被引:2,自引:0,他引:2  
以18个甘薯品种(系)为试验材料, 设置对照和200 mmol L -1 NaCl浓度处理, 通过苗期盐土栽培胁迫方式, 对各处理下各品种(系)的茎叶鲜重、根系鲜重、茎叶干重、根系干重、叶片相对电导率、Fv/Fm、SPAD值、SOD酶活性、MDA含量、脯氨酸含量、根系活力、根系Na +和K +含量、Na +/K +比值等14个生理指标进行测定, 通过对各单项指标的耐盐系数进行相关分析、主成分分析、聚类分析和逐步回归等方法对品种(系)耐盐性进行综合评价。通过主成分分析, 将盐胁迫处理下甘薯苗期的14个单项指标转换成5个彼此独立的综合指标; 通过隶属函数分析, 得到不同品种(系)苗期耐盐性综合评价值(D值), 并通过聚类分析, 将18个甘薯品种(系)划分为4种耐盐类型, 其中盐敏感型4个、弱耐盐型3个、中度耐盐型7个和高度耐盐型4个。在此基础上, 利用逐步回归方法建立了可用于甘薯苗期耐盐性评价的回归方程, 同时筛选出茎叶鲜重、根系鲜重、茎叶干重、叶片SPAD值、SOD酶活性、MDA含量、脯氨酸含量、根系Na +/K +比值等8个可用于甘薯苗期耐盐性评价的生理指标。本研究可为甘薯耐盐新品种选育提供种质并为甘薯苗期耐盐性评价及耐盐机制研究提供理论依据。  相似文献   

13.
Crop losses caused by environmental stresses might be reduced by applying osmoprotectans to crop canopies. Glycinebetaine is endogenously accumulated by some halophytes under stress conditions and represents such a compound. Glycinebetaine was applied exogenously to barley ( Hordeum vulgare L.), oat ( Avena sativa L.), spring wheat ( Triticum aestwum L.), and summer turnip rape ( Brassica rapa ssp. oleifera DC.) canopies and its optimal concentration was monitored in the greenhouse. In field experiments the response of crop plants to betaine applications was assessed by measuring accumulation of above ground biomass, leaf area index (LAI), leaf chlorophyll, and yield. The optimum betaine concentration producing advantageous effects on growth and crop physiology in turnip rape was close to 0.1 M and for wheat 0.3 M. Such concentrations promoted accumulation of betaine similar to that of halophytes under stress conditions [ca. 200 μmol (g DM)−1]. In the 1993 field experiment peak LAIs were recorded in irrigated wheat and barley treated with 17.5 kg ha−1 betaine applied at 300 1 ha−1. Green leaf area was slightly more persistent in wheat treated twice with 1 kg ha−1 betaine applied at 200 1 ha−1 in 1994, although it was not associated with increased grain yield. Our results indicated that betaine has no actual potential in Finland for the principal grain crops but further studies are needed in stress prone environments to assess the potential of betaine treatments for preventing crop failures.  相似文献   

14.
Remotely sensed infrared canopy temperatures provide an efficient method for rapid, non-destructive monitoring of whole-plant response to water stress. Field studies were conducted in 1992 and 1993 to evaluate the potential for using canopy temperatures to screen for drought tolerance in wheat. In both years, 12 spring wheat (Triticum aestivum L.) genotypes were grown under two irrigation levels (well-watered and moisture-stressed) imposed between tillering and anthesis with a line-source sprinkler irrigation system. Canopy temperature measurements were taken in well-watered and moisture-stressed plots between 1330 and 1430 h (MDT) on five clear days in 1992 and seven clear days in 1993 during the late vegetative and early reproductive growth periods following closure of the plant canopy. Genotypes exhibited differences in mean canopy temperatures across the two irrigation levels and two years. Klasic consistently had the highest canopy temperature under moisture-stressed conditions, while Bannock and Pondera had the lowest. Bannock, Yecora Rojo and Klasic had the warmest canopies under well-watered conditions, while Vandal, Amidon and Rick had the coolest. Plot-to-plot variation in canopy temperature under water stress conditions was evident for differences in grain yield. Significant correlations between canopy temperature and yield under moisture-stress conditions and drought susceptibility index values indicated the potential for screening wheat genotypes for drought response.  相似文献   

15.
The optimal N-supply in spring for different plant densities of winter wheat
The influence of plant density (plt./m2) on the optimal N-supply in spring (Nmin-content + N-fertilization) has been tested at three sites. The different plant density was produced by different seed rates in autumn of about 150, 250, 350, 450 and 550 grains/m2. The N-supply in spring was - apart from a non-fertilized field (Nmin-content) 80, 100, 120, 140 and 160 kg N/ha. Additionally, 80 kg N/ha were applicated as N-topdressing. Moreover the optimal N-supply in spring has been tested on a winter wheat field thinned out due to winterkilling. In detail we got the following results:
1. The reduction of the Nmin-content due to the N-uptake by the plants slowed down in accordance with minor plant density.
2. The same N-supply in the soil produced a higher N-supply per individual plant in accordance with decreasing plant density and lead to a considerable increase of N-nutrition.
3. Thin crops showed a higher tillering. The differences in plant density between 150 and 550 plt./m2 in spring diminished to about 90 ears/m2 at harvest.
4. Independently of plant density the maximum yield was obtained by a N-supply (Nmin+ N-fertilization) in spring of about 120 kg/ha N. Due to the abundant N-nutrition of the individual plants and the minor increase of yield a higher N-supply is not necessary with a minor plant density.
5. Essentially the yield level was only diminished with the lowest plant density (100-140 plt./m2).  相似文献   

16.
盐渍化土壤中盐胁迫是作物种子萌发和生长发育的主要限制因子, 探究盐分胁迫下提高种子萌发率的技术及机制对开发利用盐碱地有重要意义。本文以不同耐盐能力的高粱品种国甜2011和国甜106为材料, 研究了盐分对甜高粱种子萌发期生长过程的影响, 并比较了耐盐性差异。以耐盐性弱的国甜106为试材, 探究盐分胁迫下不同生长调节物质[γ-氨基丁酸(GABA)、赤霉素(GA3)、激动素(KT)和水杨酸(SA)]对甜高粱种子吸水萌发过程中生长特性的调节效应。表明, 盐分胁迫显著抑制种子的吸水萌发, 降低种子的吸水速率、发芽势、发芽率、发芽指数, 增加种子的相对盐害率和丙二醛(MDA)含量。外源生长调节物质可有效缓解盐害, 显著增加种子的吸水率、发芽率、可溶性糖含量、可溶性蛋白含量, 提高SOD (超氧化物岐化酶)、POD (过氧化物酶)、CAT (过氧化氢酶)的活性, 促进K +、Ca 2+、Mg 2+离子的吸收, 降低Na +和MDA含量。外源生长调节物质主要是通过提高保护酶活性、渗透调剂物质含量和维持体内离子平衡来提高耐盐性。GA3和GABA对盐害的缓解效应较好, 而KT促进种子对Mg 2+的吸收效果较好。本研究表明外源生长调节物质(尤其是 GA3和 GABA)可用于盐碱地高粱生产, 为减轻盐碱地对高粱的盐碱胁迫提供了理论依据。  相似文献   

17.
Particular problems in N fertilization of winter wheat are found in areas characterized by excessive drainage and rainy springs. A two yearly experiment was carried out in such an environment (Udine, northern Italy) with the objective of testing the effect of increasing levels of total N supply (0, 70, 140 and 210 kg ha−1) and of different times of late N side-dressing (at stem elongation, booting or flowering) on yield, quality traits and on N use efficiency of the wheat cv. Saliente.
The results obtained indicated that yields of about 5 t ha1 can be obtained if the N supply permits a crop recovery of 130-140 kg ha−1. Supplying the last N fraction at booting increased the fertility of the spike, the overall quality of the product and the efficiency of the fertilization. N supply can be delayed to flowering time in case of high total N, with further positive effects on the quality of the product. The nitrogen use efficiency was inversely and linearly related to total N supply.  相似文献   

18.
以100mmolL^-1NaCI处理耐盐小麦品种德抗961和盐敏感品种鲁麦15各2d,测定其胚芽鞘相对伸长速率及渗透调节能力。结果表明,NaCl处理抑制小麦胚芽鞘的伸长,其相对伸长速率最大值减小,生长最快的时间推后,但胚芽鞘最终长度没有改变;NaCI胁迫使小麦胚芽鞘渗透势下降,德抗961渗透调节能力强于鲁麦15;NaCl胁迫使小麦胚芽鞘Na^+、脯氨酸、总可溶性糖含量明显增加,德抗961增加幅度大于鲁麦15;NaCl胁迫下,德抗961胚芽鞘伸长明显好于鲁麦15,其具有较强渗透调节能力是原因之。因此,一定浓度NaCl处理下小麦胚芽鞘的长度可作为耐盐筛选的有用指标。  相似文献   

19.
The pattern of free NH4+ accumulation and its metabolism was studied during the growth and development of field-grown wheat cv. HD 2204 at two applied N levels viz. 30 and 120 kg ha−1. The study was confined to the 3rd, 5th and flag leaf blades and the developing ears, borne on the main shoot, during their ontogeny. The NH4+ levels were considerably lower in young leaves and increased sharply as the leaves senesced when the activity of glutamine synthetase (GS) declined. In contrast to GS, glutamate dehydrogenase (GDH) remained active even during senescence. Concentrations of protein, free amino acid and total reduced N declined with age in the leaves. An assessment of free NH4+ pool, free amino acid content and the activity of GS and GDH in the floral parts revealed that glumes, awns and grains also were active sites of NH4+ turnover. Higher applied N level not only increased leaf and grain N concentration but also led to higher free NH4+ levels in leaves and in developing ears. Presence of NH4+ in the entrapped transpirate revealed that NH4+ is released from both leaves and ears during senescence.  相似文献   

20.
Evaluation of commonly grown cotton (Gossypium hir-sutum L.) genotypes under saline environment may help to cope with the venture of the crop failure in salt-affected soils. In a pot experiment, four cotton genotypes (MNH-93, NIAB-78. S-12, and B-557) were grown to compare their relative performance on a sandy clay loam soil (original ECe = 1.9 dS m−1) salinized with a salt mixture (Na2SO4, NaCl, CaCl2, MgSO4 in the ratio of 9:5:5:1 on equivalent basis) to EQ levels of 10 and 20 dS m−1. The crop was raised to the flower initiation stage. The imposed salinity stress exhibited deleterious effect on the germination and vegetative growth with significant differences among the genotypes. Leaf area, stem thickness, shoot (stem + leaves) and root weights decreased with the increase in substrate salinity. NIAB-78 showed the least decline followed by MNH-93. Leaf thickness showed an opposite trend as an increase in this parameter was observed with the rising salinity, the maximum increase being in the case of NIAB-78. Analysis of the leaf sap showed increased Na+ and Cl concentrations and decreased K+ concentration with the increase in substrate salinity. A better osmotic adjustment, a lower Na+/K+ ratio and a lower Cl concentration were found in the leaves of NIAB-78 followed by MNH-93. This contributed towards their better growth performance under saline conditions.  相似文献   

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