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1.
Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotypes was tested at four salinity levels (0, 100, 200, and 300 mM NaCl in Hoagland nutrient solution) at two growth stages (germination and vegetative). The relationship between salinity tolerance and carbon isotope discrimination (CID) was also accessed. Results of the study carried out under laboratory conditions showed that a negative linear relationship was observed between salt concentration and germination as well as other growth parameters. Some genotypes showed good salt tolerance at germination but failed to survive at seedling stage. However, five genotypes, namely, Jau-83, Pk-30109, Pk-30118, 57/2D, and Akermanns Bavaria showed better tolerance to salinity (200 mM) both at germination and at vegetative growth stage. The salt tolerance of these barley genotypes was significantly correlated with minimum decrease in K+:Na+ ratio in plant tissue with increase in the root zone salinity. However, the case was reversed in sensitive genotypes. CID was decreased linearly with increase in root zone salinity. However, salt-tolerant genotypes maintained their turgor by osmotic adjustment and by minimum increase in diffusive resistance and showed minimum reduction in CID (Δ) with gradual increase in rooting medium salt concentration. Results suggested that the tolerant genotypes make osmotic adjustments by selective uptake of K+ and by maintaining a higher K+:Na+ ratio in leaves. Moreover, CID technique can also be good criteria for screening of salt-tolerant germplasm.  相似文献   

2.
The salinity tolerance of nine grape genotypes was studied. Salinity was applied as nutrient solutions containing 0, 25, 50, and 100 mM sodium chloride (NaCl) for two weeks. Growth was significantly reduced by salinity, whereas chloride (Cl?) and sodium (Na+) contents increased. Sodium ion accumulation exceeded that of Cl? in all treatments. Shirazi and H6 had higher and lower Cl? concentrations in their lamina than others. There were significant positive correlations (P < 0.01) between Cl? and Na+ and negative correlation between Na+ and potassium (K+) in roots and laminas of all genotypes. Soluble sugars, proline, and glycine betaine contents increased in laminas of all of the genotypes with moderate salinity. There were positive correlations (P < 0.01) between lamina and root Na+ and Cl? contents and compatible solutes in all genotypes. Overall results revealed that unlike Shirazi with higher Na+ and Cl? accumulation in shoot, H6 showed a higher capacity to restrict Na+ and Cl? transport to shoot.  相似文献   

3.
Identification of novel wheat (Triticum aestivum L.) germplasm is imperative to develop salt tolerant varieties. In the first phase, 400 accessions were screened against high salt stress (200 mM NaCl) on the basis of Na+ accumulation in leaf blade, and 40 genotypes with contrast reaction to salinity were selected. Salt tolerant group (25 genotypes) had higher leaf K+/Na+ ratio, maximum root and shoot lengths, leaf fresh/dry weights and chlorophyll content as compared to the salt sensitive group (15 genotypes). In second phase, physiologically based screening was performed on selected genotypes against varying salinity levels (0, 100 and 200 mM NaCl). GGE biplot analysis indicates that genotypes TURACO, V-03094, V0005, V-04178, Kharchia 65 and V-05121 were the most salt-tolerant and declared winners as depicted by more gaseous exchange relations and growth potential which was strongly correlated with proper Na+, K+ discrimination in leaf and root tissues. Genotypes PBW343*2, NING MAI 50, PGO, PFAU, V-04181, PUNJAB 85, KIRITATI, TAM200/TUI and TAM200 were poor performer due to more Na+ accumulation in leaf ultimately retarded growth. In conclusion, low Na+ accumulation in leaf can be used as the best screening criteria, employing a large set of genotypes in a breeding program.  相似文献   

4.
The sensitivity of crop genotypes determines the level of growth reduction by salinity. Effect of salinity levels (7.5 and 15 dihydrate m?1) using completely randomized design (CRD) with four replications per treatment were compared on germination, chlorophyll content, water potential, ionic sodium and potassium (Na+, K+) balance, and other growth-related parameters of six wheat genotypes for varietal differences under long-term salinity stress. Chlorophyll contents at flowering stage and yield aspects at maturity of all the wheat genotypes decreased with increasing salinity. The maximum Na+ concentration was observed at 7.5 and 15 dS m?1 in Bhakhar and Saher-2000, respectively, while minimum Na+ concentration was observed for 9476. However, the maximum K+ concentration and water potential was noticed in 9476 at 7.5 dS m?1. Careful selection of salt-tolerant genotypes for field crops is an important perspective especially in the developing countries facing salinity problem. Our results revealed that the wheat genotype 9476 performed best regarding growth and physiological parameters compared to other wheat genotypes.  相似文献   

5.
Bermudagrass (Cynodon dactylon) is a salinity-tolerant turfgrass that has good use potential in the saline-alkali lands of warm regions. However, the systematic Na+ and K+ regulation mechanisms under salinity stress remain unclear at the whole plant level. Two bermudagrass cultivars differing in salinity tolerance were exposed to 0, 50, 100, 200, or 300 mM NaCl in a hydroponic system. Growth, absorption, transportation, and secretion of Na+ and K+, and gas exchange parameters were determined in both cultivars. K+ contents were decreased and Na+ contents and Na+/K+ ratios were increased in both bermudagrasses with increased salinity; however, lower Na+ content and Na+/K+ ratio and more stable K+ content were found in the leaves of the salinity-tolerant ‘Yangjiang’ than the salinity-sensitive ‘Nanjing’. Higher Na+ contents in root cortical cells were found than in the stele cells of ‘Yangjiang’, but the opposite was observed in ‘Nanjing’. Lower Na+ contents and higher K+ contents were found in vessels for ‘Yangjiang’ than for ‘Nanjing’. Salinity stress increased the selective transport of K+ over Na+ from roots to leaves and the Na+-selective secretion via salt glands, which were stronger in ‘Yangjiang’ than ‘Nanjing’. Net photosynthetic rate and stomatal conductance decreased in the two bermudagrasses with increased salinity; however, they were more stable in ‘Yangjiang’. The results suggested that bermudagrass could reduce Na+ accumulation and maintain K+ stability in leaves under salinity stress by restricting Na+ into vessels in roots, selectively transporting K+ over Na+ from roots to leaves, selectively secreting Na+ via leaf salt glands, and maintaining suitable stomatal conductance.  相似文献   

6.
Thermography is proposed to be an alternative non-destructive and rapid technique for the study and diagnosing of salt tolerance in plants. In a pot experiment, 30 cultivars of wheat (Triticum aestivum L.) were evaluated in terms of their leaf temperature and shoot growth and their ion distribution responses to NaCl salinity at two concentration levels: the control with electrical conductivity (EC) of 1 dS m?1 and salinity treatment with EC of 16 dS m?1 (150 mM). A completely randomized block design with factorial treatments was employed with three replications. The results indicated that thermography may accurately reflect the physiological status of salt-stressed wheat plants. The salt stress-based increase in leaf temperature of wheat cultivars grown at 150 mM NaCl reached 1.34°C compared to the control. According to the results obtained, it appears that thermography has the capability of discerning differences of salinity tolerance between the cultivars. Three salt-tolerant wheat cultivars, namely Roshan, Kharchia and Sholeh, had higher mean shoot dry matter (0.039 g plant?1) and higher mean ratio of leaf K+/Na+ (14.06) and showed lower increase in the mean leaf temperature (0.37°C) by thermography compared to the control. This was while nine salt-sensitive cultivars, namely Kavir, Ghods, Atrak, Parsi, Bahar, Pishtaz, Falat, Gaspard and Tajan, had lower mean plant dry matter production (0.027 g plant?1), lower mean ratio of K+/Na+ (9.49) and higher mean increases in leaf temperature (1.24°C).  相似文献   

7.
A study of the salinity effect on mineral content in rice genotypes differing in salt tolerance was conducted in a factorial Completely Randomized Design experiment. The results indicated that the genotypes developed differently by mutation conventional breeding. NS15 represented as salt-sensitive, Pokkali was included as an internationally salt-tolerant check and Iratom24 was moderately tolerant. The content of Na+, Ca2+, Mg2+ and Cl? followed an increasing pattern in roots and shoots of all the rice genotypes due to increasing salinity levels except Ca2+ and Mg2+ in the root. However, the concentration of K+ showed more or less an increasing pattern in root and a decreasing pattern in shoot. The concentration of Na+ and Ca2+ sharply increased with increasing the salinity levels in both the roots and shoots of NS15. The concentration of K+ sharply decreased in shoot and increased in the root of susceptible genotype NS15 with increasing salinity over 6 dS m?1 salinity levels, where the transformation of K+ from root to shoot was disrupted by Na+. The Cl? content sharply increased with increasing salinity in the root of NS15 as compared to shoot. The effect of different salinity levels on Na+/K+ ratio in the shoots of the selected rice genotypes sharply increased in susceptible genotype NS15 as compared to the other genotypes.  相似文献   

8.
Soil salinity is a concern in the wake of climate change challenges due to rising sea levels and coastal salinity in Papua New Guinea. A greenhouse experiment was conducted in Split Plot design, with five elite sweet potato genotypes (main-plot factors) and three levels of sodium chlroide (NaCl) concentrations (sub-plot factors) replicated six times. The vine cuttings of genotype RAB 45 showed very low mortality percentage (33%) at 600 mM NaCl concentration. At salinity level of 200 mM NaCl, aerial dry biomass of the genotypes was inversely but significantly (r = –0.40; p < 0.05) related to the accumulation of sodium (Na+) in the tissues. The Na+ accumulation in the tissues was antagonistic to the potassium (K+) and calcium (Ca2+) ions. Among the sweetpotato genotypes, Na+/K+ ratio decreased in the following order: RAB 45> KAV 11 > Northern Star > DOY 2 > L 46, which was more or less corroborated with the trend in the aerial dry matter.  相似文献   

9.
Silicon (Si) is known to alleviate a number of abiotic stresses in higher plants including salinity stress. Two independent experiments were conducted to evaluate the role of Si in alleviating salinity stress in two contrasting wheat (Triticum aestivum L.) genotypes, Auqab-2000' (salt sensitive) and SARC-3 (salt tolerant). In the first experiment, genotypes were grown in hydroponics with two levels of salinity (0 and 60 mM NaCl) with and without 2 mM Si in a completely randomized design with four replications. Salinity stress significantly (P < 0.01) decreased all of the growth parameters, increased sodium (Na+) concentration, and decreased potassium (K+) concentration in shoots of both genotypes grown in hydroponics. Silicon significantly improved growth of both genotypes. The increase in growth was more prominent under salt stress (75%) than under normal condition (15%). In the second experiment, both genotypes were grown in normal [electrical conductivity (EC) = 1.23 d Sm–1] and natural saline field (EC = 11.92 d Sm–1) conditions with three levels of Si (0, 75, and 150 g g–1 Si) with three replications in a randomized complete block design. Silicon significantly (P < 0.05) decreased growth reduction in both genotypes caused by salinity stress. The grain yield under salt stress decreased from 62% to 33% and from 44% to 20% of the maximum potential in Auqab-2000 and SARC-3, respectively, when 150 g g–1 Si was used. Auqab-2000 performed better in normal field conditions, but SARC-3 produced more straw and grain yield in saline field conditions. Addition of Si significantly (P < 0.05) improved K uptake and reduced Na+ uptake in both of wheat genotypes and increased the K+/Na+ ratio in shoot. Enhanced salinity tolerance and improved growth in wheat by Si application was attributed to decreased Na+ uptake, its restricted translocation toward shoots, and enhanced K+ uptake.  相似文献   

10.
The experiment containing three replicates of completely randomized factorial treatments was conducted in a glasshouse under controlled conditions with three simulated soil salinity levels (control, 10 and 15 dS m?1). Morpho-physiological traits (i.e. lengths, fresh weights and dry weights of root and shoot, number of leaves, root/shoot ratio, shoot Na+ accumulation, K+/Na+ ratio, Ca2+/Na+ ratio, membrane stability index, lycopene contents, chlorophyll-a and -b) were recorded to determine mechanism of salt tolerance of tomato at seedling stage. Principal component analysis (PCA) was used to express a three-way interaction of genotype × salinity level × traits that scattered the 25 tomato genotypes based on their morpho-physiological response to different NaCl levels. The negative association of Na+ with all other traits except root/shoot ratio and the morpho-physiological response trend of genotypes exposed that probable mechanism of salt tolerance was initially Na+ exclusion by abscising older leaves to have younger physiologically energetic, and lastly a higher activity of plants for root development to sustain them in saline soil. PCA three-way biplot efficiently recognized ANAHU, LA-2821, LO-2752, LO-2707, PB-017909, LO-2831-23 and 017860 as salt tolerant genotypes. On the other hand, ZARNITZA, GLACIER, LO-2692, LO-2576, BL-1079, 006233, 006232, 017856, NUTYT-701 and NAGINA were found to be salt susceptible.  相似文献   

11.
In order to study the effects of salinity and water stress on growth and macronutrients concentration of pomegranate plant leaves, a factorial experiment was conducted based on completely randomized design with 0, 30, and 60 mM of salinity levels of sodium chloride and calcium chloride (1:1) and three irrigation intervals (2, 4, and 6 days) with 3 replications on ‘Rabab’ and ‘Shishegap’ cultivars of pomegranate. The results of the shoot and root analysis indicated that the salinity and drought affected the concentration and distribution of sodium (Na+), potassium (K+), chloride (Cl?), calcium (Ca2+), magnesium (Mg2+), and phosphorus (P+) in pomegranate leaves. Mineral concentrations of sodium (Na+), chloride (Cl-), potassium (K+), in shoots and roots were increased with increasing salinity. Drought treatments increased the concentration of Cl?, Na+, and Mg2+ in the shoot. Both cultivars showed significant differences in the concentrations of elements, however the most accumulation of Na+ and Cl? was observed in ‘Rabab,’ while the ‘Shishegap’ cultivar had the most absorption of K+. ‘Shishegap’ cultivar showed higher tolerance to salinity than ‘Rabab’ through maintaining the vegetative growth and lower chloride transport to the shoot, and improvement of potassium transport to shoot.  相似文献   

12.
We studied the growth and ionic composition of five wheat genotypes (Inqlab-91, Uqab 2002, SARC-1, SARC-3, and SARC-5) grown under salinity stress to applied silicon. Plants were grown with three levels of salinity [0, 60, and 120 mM sodium chloride (NaCl)] in the presence of 0, 2, and 4 mM Si in nutrient solution for 40 days. Salinity stress significantly decreased shoot and root biomass in plants with varying degrees. Genotype SARC-3 exhibited higher salt tolerance than other genotypes. Silicon (Si) application significantly (P < 0.05) increased plant biomass at both control as well as under saline conditions. Genotypes differed significantly for their response to applied Si in terms of biomass production. Silicon application significantly (P < 0.01) increased potassium (K+) concentration in shoots. Enhanced salinity tolerance in wheat by Si application was attributed to increased K+ uptake thereby increasing K+/sodium (Na+) ratio and lower Na+ translocation towards shoot.  相似文献   

13.
Salinity has a two‐phase effect on plant growth, an osmotic effect due to salts in the outside solution and ion toxicity in a second phase due to salt build‐up in transpiring leaves. To elucidate salt‐resistance mechanisms in the first phase of salt stress, we studied the biochemical reaction of salt‐resistant and salt‐sensitive wheat (Triticum aestivum L.) genotypes at protein level after 10 d exposure to 125 mM–NaCl salinity (first phase of salt stress) and the variation of salt resistance among the genotypes after 30 d exposure to 125 mM–NaCl salinity (second phase of salt stress) in solution culture experiments in a growth chamber. The three genotypes differed significantly in absolute and relative shoot and root dry weights after 30 d exposure to NaCl salinity. SARC‐1 produced the maximum and 7‐Cerros the minimum shoot dry weights under salinity relative to control. A highly significant negative correlation (r2 = –0.99) was observed between salt resistance (% shoot dry weight under salinity relative to control) and shoot Na+ concentration of the wheat genotypes studied. However, the salt‐resistant and salt‐sensitive genotypes showed a similar biochemical reaction at the level of proteins after 10 d exposure to 125 mM NaCl. In both genotypes, the expression of more than 50% proteins was changed, but the difference between the genotypes in various categories of protein change (up‐regulated, down‐regulated, disappeared, and new‐appeared) was only 1%–8%. It is concluded that the initial biochemical reaction to salinity at protein level in wheat is an unspecific response and not a specific adaptation to salinity.  相似文献   

14.
ABSTRACT

An experiment was conducted in a randomized factorial design with three replicates to elucidate the comparative tolerance of tomato genotypes and hybrids against salinity (NaCl) and nickel (Ni) toxicity. Six tomato genotypes and two hybrids were exposed to different levels of NaCl (0, 75 and 150 mM) and Ni (0, 15 and 20 mg L?1) in hydroponics for 4 weeks. Increasing levels of NaCl and Ni significantly decreased the growth of all the genotypes. Cluster analysis for relative tolerance of the genotypes and hybrids showed that the genotype “Naqeeb” is the most tolerant whereas the genotype “Nadir” proved to be the most sensitive against both the NaCl and Ni-toxicity. Leaf tissues Na+ and Ni concentration significantly increased by increasing NaCl and Ni levels in the growth medium with tolerant genotype “Naqeeb” showing the lowest and sensitive genotype “Nadir” with the highest concentration. Antagonistic relation between uptake of Na+ and Ni was observed in all the genotypes and hybrids. Results revealed that tomato genotypes and hybrids shared the same defense mechanism against salinity and Ni-toxicity tolerance. The genotypes tolerant against one stress can be regarded as tolerant against other stress as well.  相似文献   

15.
Twenty genotypes of wheat resulting from different crossings between some wheat parental lines were compared for salt stress (control and gradually increasing salinity). Ion content in root, shoot, and flag leaves and also the root and shoot dry weights were measured. Based on these results, eight genotypes among the twenty were selected as susceptible, semi-tolerant, and tolerant genotypes for evaluating their biochemical characteristics. Results indicated that concentration of sodium (Na+) and potassium (K+) in shoot, root, and flag leaves of stressed plants were, respectively, higher and lower than that in the non-stressed plants. Overall, salinity stress caused reductions in root and shoot dry weights and relative water content (RWC), but enhancement in pigments content. Concentrations of the total carbohydrate, total protein, and soluble proline were higher in plants under salt stress condition. Salinity stress induced higher production in hydrogen peroxide (H2O2) and malondialdehyde (MDA) and also higher activity of catalase (CAT) and ascorbic peroxidase (APX) as antioxidant enzymes, but lower activity of peroxidase (POD). Genotypes 4s, Arg, and 386dh had generally higher enzymatic activity and other tolerant indices, and hence they can be introduced as tolerant genotypes for more study by the plant breeders. On the other hand, genotype 278s was most susceptible based on the most results.  相似文献   

16.
Pistachio is one of the most important horticultural crops in Iran. The majority of the pistachio producing regions is located in arid and semi-arid areas with saline conditions. Therefore, selection of suitable rootstocks is important for increasing yield efficiency of this important nut crop. In this study, the effect of four water salinity levels (0.75, 5, 10 and 15 ds m?1) on growth indices and physiological parameters of four Pistacia vera L. rootstocks (Badami-e-Zarand A, Badami-e-Zarand B, Qazvini, and Sarakhs) were investigated under greenhouse conditions. After treatment for three months, leaf dry weight was reduced by about 30-50% at an irrigation water electrical conductivity (ECw) of 10 ds m?1. Badami-e-Zarand B was the most vigorous rootstock at the highest EC. Decreases in root and stem dry weight (average of all rootstocks combined) occurred at water salinity of 10 ds m?1. Chemical analysis of shoot and root indicated that the salinity affected the concentration and distribution of sodium (Na+), potassium (K+), and calcium (Ca2+) in pistachio rootstocks. The concentrations of Na+ and K+ increased with a rise in water salinity levels. Comparison between Na+ concentration of shoot and root showed that all examined rootstocks limited the Na+ transportation to shoot tissue up-to 15 ds m-1, and retained it in the roots. However, this ability was less in the Sarakhs rootstock. Based on measured parameters, Badami-e-Zarand B and Sarakhs could be considered as tolerant and sensitive pistachio rootstocks to water salinity, respectively.  相似文献   

17.
Bermudagrass (Cynodon dactylon (L.) Pers.) is a widely used warm-season turfgrass and has the highest nitrogen (N) fertilization requirements among turfgrasses. Wild ecotype found in N-poor habitats can potentially tolerant N limiting conditions for reducing N inputs in the turf industry. However, the extent of variation in their low N tolerance has remained unclear. We conducted hydroponic experiments to evaluate the variation on growth, N accumulation, and partitioning of wild bermudagrass from China pre-core collection under normal (5 mM) and limited (0.05 mM) N levels in two experiments. The results showed that low N nutrition significantly decreased clipping growth, while had no effects on verdure and root growth; in addition, the magnitude of clippings N accumulation reduction was higher than verdure and root across all accessions. However, significant genetic variations in all studied traits except for root N content in experiment 2 were found among accessions. Using a cluster analysis, 56 accessions in experiment 1 and 12 accessions in experiment 2 were classified into four groups and two groups separately. The accessions with superior low N tolerance had improved growth and accumulated more N in the verdure and roots; it is interesting that other accessions with low N tolerance had different tolerance mechanisms and transferred more N nutrition from the roots to the clippings to maintain better turf quality. The different molds in low N tolerance suggest that there is much potential for improving low N tolerance among Chinese natural bermudagrass accessions.  相似文献   

18.
ABSTRACT

The effects of three sodium chloride (NaCl) levels (0, 1200, and 2400 mg kg? 1 soil) and three irrigation intervals (3, 7, and 14 d) on the growth and chemical composition of two Pistacia vera rootstocks (‘Sarakhs’ and ‘Qazvini’) were investigated under greenhouse conditions. Eight-week-old pistachio seedlings were gradually exposed to salt stress which afterward, water stress was initiated. At any irrigation interval, plant height and shoot and root dry weights of both rootstocks were reduced with increasing salinity. However, increasing irrigation intervals alleviated the adverse effects of soil salinity. A negative relationship observed between relative shoot growth and electrical conductivity of soil saturation extract (ECe) confirmed the above findings. Under 3-d irrigation interval, the ECe required to cause a 50% growth reduction was lower than those under 7- and/or 14-d irrigation intervals. Shoot and root chemical analyses indicated that the salinity as well as irrigation regime affected the concentration and distribution of sodium (Na+), potassium (K+), and chloride (Cl?) in pistachio. The concentration of Na+, K+ and C1? ions increased with a rise in NaCl level, and was generally declined with increasing irrigation interval. Based on plant height, shoot and root dry weights and the concentrations of Na+, K+, and C1? in the plant tissues, at lowest irrigation intervals ‘Sarakhs’ shows a higher sensitivity to soil salinity than ‘Qazvini’, but with increasing irrigation interval, ‘Sarakhs’ and ‘Qazvini’ can be classified as resistant and sensitive to salinity, respectively.  相似文献   

19.
局部根系盐胁迫对冬小麦生长和光合特征的影响   总被引：3，自引：1，他引：2  
通过分根装置设置无盐胁迫(0|0)、局部根系150 mmol-L-1NaCl胁迫(0|150)、全部根系75 mmol-L-1NaCl胁迫(75|75)、全部根系150 mmol-L-1NaCl胁迫(150|150)4种处理,研究根系局部盐胁迫对冬小麦生长及光合特征的影响。结果表明:盐胁迫显著抑制了小麦幼苗的生长,并且随着盐胁迫浓度的增加,小麦受抑制程度加重;根系盐胁迫方式对小麦幼苗生长影响显著,局部根系胁迫处理(0|150)小麦幼苗地上部干重比等浓度150 mmol-L-1NaCl全部盐胁迫处理(150|150)增加23.5%,比等浓度75 mmol-L-1NaCl全部盐胁迫处理(75|75)增加17.2%。在局部根系盐胁迫下,非盐胁迫一侧根系(0|150-0)补偿生长,其根长、侧根数、侧根长比盐胁迫一侧根系(0|150-150)分别增加195.2%、206.2%和237.8%,盐胁迫一侧根系吸收的Na+部分向非盐胁迫一侧根系运输,盐胁迫一侧根系(0|150-150)的Na+含量比全部胁迫处理(150|150)减少12.1%。与全部根系盐胁迫相比,局部根系盐胁迫减少了Na+在叶片中的积累,降低了钠/钾值。局部根系盐胁迫叶片净光合速率、气孔导度、胞间CO2浓度和叶绿素荧光参数(Fv/Fm)均高于同浓度完全盐胁迫处理的小麦幼苗,进而增加地上部和根系的生物量。因此,局部根系胁迫显著缓解了全部盐胁迫对小麦地上部和根系生长的抑制作用。  相似文献   

20.
【目的】土壤盐碱化是制约农作物产量的主要因素之一,盐胁迫影响养分运输和分布,造成植物营养失衡,导致作物发育迟缓,植株矮小,严重威胁着我国的粮食生产。在必需营养元素中,氮素是需求量最大的元素,NO-3和NH+4是植物吸收氮素的两种离子形态。植物对盐胁迫的响应受到不同形态氮素的调控,研究不同形态氮素营养下植物的耐盐机制对提高植物耐盐性及产量具有重要的意义。【方法】本文以喜硝植物油菜(Brassica napus L.)和喜铵植物水稻(Oryza sativa L.)为试验材料,采用室内营养液培养方法,研究了NO-3和NH+4对Na Cl胁迫下油菜及水稻苗期生长状况、对Na+运输和积累的影响,以对照与盐胁迫植株生物量之差与Na+积累量之差的比值,评估Na+对植株的伤害程度。【结果】1)在非盐胁迫条件下,硝态氮营养显著促进油菜和水稻根系的生长;盐胁迫条件下,油菜和水稻生物量均显著受到抑制,Na Cl对供应铵态氮营养植株的抑制更为显著。2)盐胁迫条件下,两种供氮形态下,油菜和水稻植株Na+含量均显著增加,硝态氮营养油菜叶柄Na+显著高于铵态氮营养,叶柄Na+含量/叶片Na+含量大于铵营养油菜,硝态氮营养水稻根系Na+含量显著低于铵营养,地上部则相反。3)铵营养油菜和水稻Na+伤害度显著高于硝营养植株。4)盐胁迫条件下,硝态氮营养油菜地上部和水稻根系K+含量均显著高于铵态氮营养。5)盐胁迫条件下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株。【结论】与铵营养相比,硝营养油菜和水稻具有更好的耐盐性。硝态氮处理油菜叶柄Na+显著高于铵态氮处理,能够截留Na+向叶片运输。同时,供应硝态氮营养更有利于油菜和水稻吸收K+,有助于维持植物体内离子平衡。盐胁迫下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株,表明硝态氮营养油菜和水稻木质部-韧皮部对离子有较好的调控能力,是其耐盐性高于铵营养的原因之一。  相似文献   

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