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1.
《Plant Production Science》2013,16(4):453-461
Abstract

Effects of NaCl on the growth, ion content, root cap structure and Casparian band development were examined in four rice (Oryza sativa L.) cultivars with different salt resistance (salt-sensitive indica-type IR 24 and japonica-type Nipponbare and salt-resistant indica-type Nona Bokra and Pokkali). Experiments were conducted to find the differences in salinity resistance during early seedling and developed seedling stages among the cultivars. For salinity treatment, sodium chloride (NaCl) was added to nutrient solution at concentrations of 0, 25 and 50 mM for 7 days from germination to the 7th day (early seedling stage) or from the 7th day to 14th day (developed seedling stage). Growth inhibition by salinity was more prominent in the early seedling stage than in the developed seedling stage. Based on the growth, the order of the sensitivity was IR24 > Nipponbare > Nona Bokra > Pokkali. The growth of NaCl-treated rice cultivars relative to control was significantly and negatively correlated with the Na+ content and Na+/K+ ratio in roots and shoots in both stages. Scanning electron microscopic observation revealed that the root cap tissues proliferated and extended to the basal part of the root tip by salinity. The length of root cap was, however, reduced by 50 mM NaCl in sensitive cultivars due to peeling off. An endodermal Casparian band was formed in the basal region of the root tip. Development of the Casparian band was more prominent in sensitive cultivars than in tolerant cultivars. Root cap proliferation might be related to NaCl resistance in rice seedlings, but the Casparian band may not function efficiently in Na+ exclusion. Essentially the present results suggest that exclusion of Na+ from roots plays a critical role in expression of Na+ resistance in rice seedlings and the root cap is important for Na+ exclusion.  相似文献   

2.
盐胁迫浓度和胁迫时的温度对水稻耐盐性的影响   总被引：15，自引：1，他引：15  
 在水培条件下，用5种不同浓度的NaCl溶液对20个水稻品种的3~4叶期幼苗进行盐胁迫处理，10 d后考查不同品种单株盐害级别、苗高、茎叶干重和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比等性状。结果表明，0.5%的NaCl胁迫下，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差异最大；0.8%的NaCl胁迫下，品种间的相对苗高和相对茎叶干重差异最大。其中韭菜青、农林72、80 85、洞庭晚籼和丁旭稻为强耐盐水稻品种；Pokkali、IR26、小白芒、勐旺谷、明恢63为耐盐或中度耐盐品种。进一步选择8个耐盐性不同的水稻品种，在3种温度条件下进行苗期耐盐性鉴定，发现在相对低温[昼/夜为(23±3)℃/(15±1)℃\]时，水稻生长缓慢，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均较低；在温度较高[昼/夜为(36±1)℃/(26±2)℃\]时，水稻生长加快，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均增高；只有在适温条件[昼/夜为(30±2)℃/(24±2)℃\]下，水稻生长较快，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差别最明显。提出在适温条件下，以0.5%或0.8%的NaCl浓度进行水稻品种耐盐性的筛选和耐盐特性的遗传研究比较合适。  相似文献   

3.
Genome duplication improves rice root resistance to salt stress   总被引：2，自引：0，他引：2  

Background

Salinity is a stressful environmental factor that limits the productivity of crop plants, and roots form the major interface between plants and various abiotic stresses. Rice is a salt-sensitive crop and its polyploid shows advantages in terms of stress resistance. The objective of this study was to investigate the effects of genome duplication on rice root resistance to salt stress.

Results

Both diploid rice (HN2026-2x and Nipponbare-2x) and their corresponding tetraploid rice (HN2026-4x and Nipponbare-4x) were cultured in half-strength Murashige and Skoog medium with 150 mM NaCl for 3 and 5 days. Accumulations of proline, soluble sugar, malondialdehyde (MDA), Na+ content, H+ (proton) flux at root tips, and the microstructure and ultrastructure in rice roots were examined. We found that tetraploid rice showed less root growth inhibition, accumulated higher proline content and lower MDA content, and exhibited a higher frequency of normal epidermal cells than diploid rice. In addition, a protective gap appeared between the cortex and pericycle cells in tetraploid rice. Next, ultrastructural analysis showed that genome duplication improved membrane, organelle, and nuclei stability. Furthermore, Na+ in tetraploid rice roots significantly decreased while root tip H+ efflux in tetraploid rice significantly increased.

Conclusions

Our results suggest that genome duplication improves root resistance to salt stress, and that enhanced proton transport to the root surface may play a role in reducing Na+ entrance into the roots.  相似文献   

4.
为研究盐胁迫下小麦维持钾、钠平衡的生理机制,以耐盐小麦沧麦6005和盐敏感小麦矮抗58为材料,利用TEA、NEM、Ba(NO_3)_2三种药物分别抑制钾离子通道、钾载体及非选择性阳离子通道,测定正常及盐胁迫下小麦叶片K~+、Na~+含量,比较耐盐性不同的小麦品种在K~+、Na~+吸收中的差异。结果显示,盐胁迫下,沧麦6005和矮抗58叶片K~+含量下降,Na~+含量增加;沧麦6005叶片Na~+含量低于矮抗58,K~+/Na~+比值高于矮抗58。正常条件下,NEM、TEA处理均可降低沧麦6005和矮抗58叶片K~+含量,NEM处理较TEA处理效果更为明显;TEA处理显著降低了盐胁迫下矮抗58叶片K~+含量,而NEM处理则明显降低了盐胁迫下沧麦6005的叶片K~+含量;TEA、NEM、Ba(NO_3)_2处理降低了盐胁迫下矮抗58叶片Na~+含量,仅NEM处理降低了沧麦6005叶片Na~+含量。综上所述,正常条件下,钾载体是小麦K~+吸收的主要方式;盐胁迫下,耐盐品种和盐敏感品种K~+吸收途径不同,耐盐品种的NSCCs和钾离子通道具有更强的"拒钠"能力。  相似文献   

5.
外源硅对NaCl胁迫下小麦幼苗生长及光合特性的影响   总被引：4，自引：0，他引：4  
为探讨外源硅对小麦幼苗耐盐性的调节作用,以抗盐小麦品种德抗961和非抗盐小麦品种泰山9818为材料,通过水培试验,研究了外源硅对NaCl胁迫下小麦幼苗生长、叶绿素含量和光合特性的影响。结果表明,在100mmol·L-1 NaCl胁迫下,随着外源硅浓度(0~3.0mmol·L-1)的增加,德抗961和泰山9818的株高、次生根数量、茎叶干重、根干重不断增加,叶片叶绿素、叶绿素a和叶绿素b含量先降后升,净光合速率及气孔导度逐渐升高,细胞间隙CO2浓度逐渐下降,气孔限制值先升后降。说明适量施硅可显著提高小麦抗盐性。  相似文献   

6.
This study characterized Pokkali-derived quantitative trait loci (QTLs) for seedling stage salinity tolerance in preparation for use in marker-assisted breeding. An analysis of 100 SSR markers on 140 IR29/Pokkali recombinant inbred lines (RILs) confirmed the location of the Saltol QTL on chromosome 1 and identified additional QTLs associated with tolerance. Analysis of a series of backcross lines and near-isogenic lines (NILs) developed to better characterize the effect of the Saltol locus revealed that Saltol mainly acted to control shoot Na+/K+ homeostasis. Multiple QTLs were required to acquire a high level of tolerance. Unexpectedly, multiple Pokkali alleles at Saltol were detected within the RIL population and between backcross lines, and representative lines were compared with seven Pokkali accessions to better characterize this allelic variation. Thus, while the Saltol locus presents a complex scenario, it provides an opportunity for marker-assisted backcrossing to improve salt tolerance of popular varieties followed by targeting multiple loci through QTL pyramiding for areas with higher salt stress.  相似文献   

7.
采用水培法研究外源硅对盐胁迫下玉米幼苗可溶性糖、游离氨基酸等渗透调节物质含量的影响。结果表明,盐胁迫下适量的增加硅供应能增加叶片和根系中渗透调节物质含量,其中根系中游离氨基酸、可溶性蛋白和可溶性糖含量的增加幅度大于叶片;同时能增加玉米幼苗各器官K+的含量,降低不同部位Na+含量,维持玉米幼苗体内的离子平衡。研究表明,硅参与盐胁迫下渗透调节物质在植物中的运输和分配,适宜浓度的硅能提高玉米耐盐性。  相似文献   

8.
《Plant Production Science》2013,16(3):319-326
Abstract

We investigated the mechanisms of increased sensitivity to Na+ in the apical and basal regions of the rice leaf under salinity. Three-week-old plants were treated with 200 mM NaCl in hydroponic culture for 3 d. Segments 6 cm in length were obtained from the apical and basal regions of the fully expanded uppermost leaves (6th leaf blades) as old and young tissues, respectively. In the plants exposed to 200 mM NaCl, Nitro blue tetrazolium (NBT) reducing activity, and H2O2 and Malondialdehyde (MDA) contents significantly increased, accompanied by the swelling of thylakoids and destruction of thylakoid membranes in the apical regions. However, no indication of oxidative damages was observed in the basal region, even though the Na+ content in the basal region was comparable to that in the apical region. In the apical region, the capacity to scavenge H2O2 was lower than that in the basal region due to decrease in the constitutive levels of ascorbate peroxidase and guaiacol peroxidase. In addition, the activities of antioxidant enzymes except superoxide dismutase and guaiacol peroxidase decreased drastically after 48 hr of exposure to NaCl. By contrast, the activities of catalase and glutathione reductase in the basal region increased compared with those in the control, and other antioxidant enzymes did not decrease under salinity during the experimental period. These results suggest that the capacity to scavenge reactive oxygen species decreased with age, and thus the apical region of the leaf blade suffered severer damage by Na+ than the basal region.  相似文献   

9.
选取耐盐性较强的水稻株系‘Fl478’、‘JX99’、‘Pokkali’和盐敏感型品种‘IR29’,设置 6 个 NaCl 浓度梯度处理, 分别为 0、0.1%、0.2%、0.3%、0.4%、0.5%,采用桶栽土培的方法培育至孕穗期,研究盐胁迫对孕穗期水稻植株不同 器官 Na+ 、K+ 分配规律与积累的影响。结果表明：（1）盐胁迫下水稻株系不同器官 Na+ ,K+ 的积累效应存在差异,水稻 株系耐盐性的差异主要表现在根系,而叶鞘对 Na+ 、K+ 的吸收与分配的差异明显。（2）耐盐植株根系聚 Na+ 能力较强, 叶片、叶鞘积累较多的 K+ ,而感盐品种根系积累 K+ 和 Na+ 以缓解根系渗透胁迫,调节根系 Na+ /K+ 平衡稳态,保持水稻 正常的代谢活动。（3）叶鞘是水稻植株关键的 Na+ -K+ 调库,通过吸收和分配 Na+ 来调节根、叶、叶鞘 Na+ /K+ 平衡以提 高水稻耐盐性。（4）耐盐株系叶鞘向叶片选择运输 K+ 的能力、限 Na+ 运输能力强于盐敏感品种,叶鞘对 Na+ 、K+ 吸收 与分配运输能力的大小,决定水稻株系的耐盐性,具体表现耐盐品种叶鞘向吸收与运输 K+ 能力较强、根系限 Na+ 能力 显著高于感盐植株。（5）0.4%~0.5%盐浓度限制水稻叶鞘 Na+ -K+ 库吸收与分配能力,各组织中 Na+ /K+ 失衡,植株耐盐 性降低,受盐害程度加深。（6）盐胁迫促进水稻株系叶鞘向根系吸收较多 Na+ 和向叶片、根系输出 K+ ,却限制 Na+ 对 叶片的分配,保证根系保持较高的 K+ /Na+ ,耐盐幼嫩叶片积累较多的 K+ 以维持叶片组织保卫细胞渗透平衡,保证水稻 植株获得生活必需的光合原料,而盐敏感植株积累的 K+ 主要用于缓解组织渗透胁迫,以维持正常生命活动。  相似文献   

10.
研究不同供磷水平对NaCl胁迫下玉米幼苗有机渗透调节物质和离子含量的影响。结果表明,盐胁迫下低磷处理玉米幼苗叶片中可溶性糖和游离氨基酸增加,根系中显著降低;增加供磷水平,叶片中可溶性糖和游离氨基酸含量下降,根系中含量上升,同时叶片和根系中可溶性蛋白含量增加。磷可降低盐胁迫下玉米幼苗各器官中的Na~+含量,同时增加各器官的K~+、Ca~(2+)和Mg~(2+)含量,降低Na~+/K~+与Na~+/Ca~(2+)比值。磷有助于维持植株的碳氮代谢平衡,促进有机渗透调节物质的运输与分配,改善各器官的离子平衡,增强植株的渗透调节能力,从而缓解盐胁迫带来的伤害。  相似文献   

11.
《Field Crops Research》2005,91(2-3):345-354
The performance of selected salt-tolerant genotypes of durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.], derived from field and in vitro assessment methods, was evaluated under greenhouse and field conditions. Eight durum wheat genotypes comprising three salt-tolerant genotypes and one salt-sensitive genotype selected from each of the methods were used. This study was conducted under both saline and non-saline field conditions as well as under greenhouse condition with salinized solution culture at 0 mM (control), 75 and 150 mM NaCl (concentrations) using supplemental Ca2+. Days to heading, days to maturity, plant height, number of grains per spike, grain weight per spike, 1000 grain weight, number of spikes per m2, grain yield and harvest index were recorded in the field experiments. Plant dry weight, Na+, K+ and Ca2+ accumulated in the hydroponically grown seedlings were measured 20 days after salinity treatments. In spite of the smaller range of genotypes used by the in vitro screening method, tolerant genotypes screened by the in vitro method (ITGs) performed comparably with those of the field-derived tolerant genotypes (FTGs) for grain yield under saline field conditions. Field salinity significantly reduced (P < 0.01) means of all traits averaged on eight tested genotypes. In vitro salt-tolerant genotypes Dipper-6 and Prion-1 produced the highest dry weight and K+/Na+ ratio under salt stress conditions (150 mM NaCl) in the greenhouse. Although dry matter correlated with the grain yield (R2 = 0.37), the regression coefficient was higher for shoot K+/Na+ ratio (R2 = 0.44). Dipper-6 (ITG) and Prion-1 (ITG) genotypes have been ranked superior while Massara-1 (ISG) was inferior for salt tolerance in the regression analysis. However, based on grain yield reduction Ajaia/Hora/Jro/3/Gan (FTG) and PI40100 (ITG) were the most tolerant having 58% and 60% reduction, respectively.  相似文献   

12.
盐胁迫对小麦根系氧化损伤及细胞程序性死亡的影响   总被引：1，自引：0，他引：1  
为探究小麦根系响应盐胁迫逆境的生理机制,以耐盐性不同的三个春小麦品种新春11号(高耐)、新春29号(中耐)和新春6号(盐敏感)为材料,分析300 mmol·L~(-1)NaCl胁迫对耐盐性不同的小麦品种根系生长、活性氧含量、抗氧化酶活性及细胞程序性死亡的影响。结果表明,与对照相比,盐胁迫下三个品种根长显著下降,根系干、鲜重均呈下降趋势,新春11号和新春29号变化幅度较小,而新春6号变化幅度相对较大;根尖中超氧阴离子产生速率保持增长趋势,耐盐性强的品种上升速率慢于耐盐性弱的品种,过氧化氢含量先增后降,最后与对照基本相同。超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性均在盐胁迫初期快速上升,胁迫30min后开始下降。SOD活性在耐盐性强的小麦品种中显著升高,而APX活性在耐盐性弱的品种中则显著升高。Evans Blue染色结果发现,随着盐胁迫时间的增加,死亡细胞数目逐渐增多。聚丙烯酰胺凝胶电泳显示,盐胁迫4h后即可检测到DNA片段化的发生,表明NaCl胁迫对小麦造成氧化损伤,诱导小麦根尖发生细胞程序性死亡。  相似文献   

13.
Abstract

The effects of exogenously applied glycinebetaine on the salt-stress-induced inhibition of growth and ultrastructural damages in rice seedlings were investigated. Glycinebetaine was not effective in alleviating the NaCl-induced inhibition of root growth and rather enhanced the NaCl-induced inhibition. However, it was found to alleviate the inhibition of shoot growth induced by NaCl stress. Concentrations of Na were higher in salt-stressed plants than in unstressed plants. Stressed plants receiving glycinebetaine had a significantly lower Na and higher K concentrations in the shoots than the plants grown without application of glycinebetaine. Salinity induced ultrastructural damages in leaf such as swelling of thylakoids, disintegration of grana stacking and intergranal lamellae and destruction of mitochondria (deficiency of cristae, swelling and vacuolation). Such damages were largely prevented by pretreatment with glycinebetaine resulting in greening of the plants. In roots, the epidermis, cortex and root cap were more sensitive to salt stress than the meristem and stele. The most frequently observed ultrastructural alteration due to NaCl salinity was the formation of many large vacuoles in the root tip and root cap cells. The number of mitochondria was increased and they were aggregated in the cytoplasm of the root tip and root cap cells by treatment with NaCl or NaCl plus glycinebetaine. Glycinebetaine could not prevent the NaCl-induced ultrastructural damages in root cells. The effects of glycinebetaine to mitigate the ultrastructural damages in the chloroplast and mitochondria induced by NaCl might be due to the production of many vacuoles in root cells which may act to store Na and decrease its accumulation in the shoot.  相似文献   

14.
选取较耐盐的水稻品种‘HH11’、‘JX99’和盐敏感水稻品种‘YSXD’,设置6个土壤NaCl浓度处理(0、1、2、3、4 g/kg),在防雨棚下盆栽并培育至孕穗期,分析NaCl胁迫对不同耐盐性水稻生理生化及光合特性的影响,结果表明:(1)NaCl胁迫抑制水稻的生长,表现为随着NaCl浓度增加,水稻的株高逐渐降低,但在3～4 g/kg土壤含盐量下耐盐水稻的株高显著高于盐敏感水稻品种。(2)耐盐水稻和盐敏感水稻的可溶性总糖对NaCl胁迫的响应差异明显,在1～4 g/kg NaCl胁迫下,盐敏感水稻叶片可溶性总糖显著降低,但是耐盐水稻可溶性总糖大量合成并积累,并且显著高于盐敏感品种。(3)NaCl浓度增加迫使水稻叶片丙二醛不断积累,导致细胞膜透性逐渐增大,但是耐盐水稻丙二醛的积累量较少,细胞膜受盐害程度显著小于盐敏感水稻。(4)NaCl胁迫抑制了水稻光合速率,但不同的NaCl浓度下导致水稻品种光合速率下降的原因各有差异,其中在0～1 g/kg NaCl胁迫下盐敏感水稻光合速率降低是非气孔因素导致的,而在2～4 g/kg NaCl胁迫下是由气孔因素造成的;0～2g/kg盐浓度下耐盐水稻HH11的光合速率降低是非气孔因素导致的,3～4 g/kg盐浓度处理是由气孔因素导致的;气孔因素是0～4 g/kg盐处理耐盐水稻JX99的光合速率降低的主要原因。(5)盐胁迫下耐盐水稻的叶片蒸腾速率显著降低,并且显著低于盐敏感水稻,相反水分利用效率和气孔限制值却明显升高,并且显著高于盐敏感水稻品种,表明盐浓度增加迫使耐盐水稻气孔阻力增大,减少水分的流失,抑制了蒸腾速率,使耐盐水稻叶片保持较高的水势;同时提高了叶片水分利用效率,碳同化效率提高,以满足耐盐水稻正常代谢生理需求,进行正常生命活动。  相似文献   

15.
Seabuckthorn (Hippophae rhamnoides L.) is uniquely capable of growing well under various extreme environmental conditions, such as water deficit, salt stress, low temperature, and high altitude. It is of economic value and its berries are used in cosmetics and pharmaceutical products. In this study, we compared the effects of salt stresses (9:1 molar ratio of NaCl to Na2SO4, pH 6.48–6.65) and alkali stresses (9:1 molar ratio of NaHCO3 to Na2CO3, pH 8.70–8.88) on the levels of inorganic ions and organic acids in H. rhamnoides L. to elucidate the physiological mechanism by which it tolerates salt or alkali stress (high pH). The results showed that, in leaves and stems under alkali stress, the Na+ content increased to a much greater extent than under salt stress. Neither salt nor alkali stress decreased the K+ content in leaves and stems; however, in roots, the K+ content decreased sharply with increasing alkali stress, whereas it remained relatively unchanged with increasing salt stress. This revealed a specific mechanism of absorption or transport for Na+ and K+ that was affected strongly by alkali stress. The results indicated that accumulation of organic acid (OA) was a central adaptive mechanism by which H. rhamnoides maintained intracellular ionic balance under alkali stress. OA may play different roles in different organs during adaptation to alkali stress, and its percentage contribution to total negative charge was higher in leaf than in stem. H. rhamnoides accumulated mainly malate, oxalate, and citrate in leaves and stems; however, in roots, less malate and citrate was accumulated, and acetate accumulation was enhanced significantly, which indicated that roots and shoots use different mechanisms to modulate OA metabolism.  相似文献   

16.
《Plant Production Science》2013,16(3):249-253
Abstract

NH3 emission from leaves of three rice (Oryza sativa L.) cultivars, Akenohoshi, Shirobeniya and Kasalath, was examined using a simple open chamber system.　In the three cultivars, NH3 emission rate (AER) and NH4+ content of leaves decreased with decreasing NH4+ concentration in the root medium, but these values differed significantly with the cultivar. In the daytime, AER, NH4+ content and glutamine synthetase (GS) activity in leaves changed similarly with maximum values around midday. Akenohoshi showed significantly lower AER and NH4+ content but higher GS activity than Kasalath. The difference in AER among the rice cultivars may be related to the activity of GS involved in photorespiratory NH3 recycling. Akenohoshi can be a breeding material useful for improving N recycling.  相似文献   

17.
This study determined the indirect selection index of doubled haploid(DH) rice using a multivariate analysis approach to select lines adaptive to salinity stress, comprising three experiments. The first experiment involved the selection of good agronomic characters in a field experiment conducted at an experimental station in Bogor, Indonesia. The second experiment involved salinity tolerance screening through hydroponic cultures using 0 and 120 mmol/L NaCl, conducted at a greenhouse in Bogor. The third experiment involved the validation of the indirect adaptability selection index(IASI) through a field experiment in Sukra(saline area). Field experiments followed a randomized complete block design(RCBD), whereas an RCBD nested factorial design was used for the greenhouse experiment. The first and second experiments used 56 DH lines and four check varieties with three replications. In the second experiment, Pokkali and IR29 varieties were also added as tolerant and sensitive checks of salinity, respectively. The third experiment used 28 selected DH lines, Inpari 29 and one sensitive DH line. The good agronomic index(GAI) was 0.465 yield + 0.433 number of productive tillers + 0.31 number of filled grains. This generated 24 DH rice lines with good agronomic traits. The salinity tolerance index(SaTI) was developed through the average of standardized salinity tolerance score and salinity selection index based on discriminant analysis. This generated 34 DH rice lines with good salinity stress tolerance. The IASI(IASI = GAI – Sa TI) selected 28 DH rice lines adaptive to salinity stress and it was considered effective by Sukra validation.  相似文献   

18.
小黑麦萌发期耐盐性评价   总被引：2，自引：0，他引：2  
为了解不同基因型小黑麦萌发期的耐盐能力,以87份小黑麦品种(系)为材料,分析了不同浓度NaCl溶液(100～250mmol·L-1)处理后小黑麦种子萌发的变化。结果表明,200～250mmol·L-1 NaCl对小黑麦种子萌发影响显著。在200mmol·L-1 NaCl胁迫下,可以鉴别不同小黑麦材料的耐盐性差异。利用200mmol·L-1 NaCl胁迫下的发芽势、发芽率、发芽指数、活力指数及幼苗干重的耐盐系数进行聚类分析,87份材料中,耐盐性较强的材料有32份,中间型有14份,盐敏感型41份。  相似文献   

19.
Summary

Use of saline drainage water for crop irrigation was evaluated as a means of decreasing its volume. Results of a nine-year crop rotation (cotton-cotton-safflower, × 3) in which only the cotton was irrigated with drainage water of 400, 1,500, 3,000, 4,500, 6,000, and 9,000 ppm total dissolved salts are presented. The different salinity levels of irrigation waters were achieved by mixing nonsaline canal water (400 ppm) and saline drainage water. Cotton lint yields were not affected by increased salinity level of the irrigation water for the first two years. Detrimental effects became evident in the third cotton crop with increasing severity in later years. In the fifth year of cotton (seventh year of the study), lint yields were adversely affected by waters of salinity greater than 3,000 ppm. However, fiber quality remained unaffected at all levels of irrigation water salinity. The reductions in lint yield appeared to be a function of time and the salinity level of applied water. Shoot height and biomass were reduced by the irrigation water salinity before lint yields. Stand establishment appeared to be the most sensitive to salinity and was perhaps the main reason for yield reduction. Increase in irrigation water salinity increased Na+ content of leaf blades and petioles and decreased K+/Na+ ratio of leaf blades and petioles. The study showed that irrigation waters of up to 3,000 ppm salinity may be used for four years without any yield reductions, as long as some leaching occurs through preplant irrigations with low salinity water. Data on crop growth and development and ionic content collected over the nine year period are presented.  相似文献   

20.
复合盐胁迫对小麦萌发的影响及耐盐阈值的筛选   总被引：2，自引：0，他引：2  
为了解Na2SO4和NaCl组成的复合盐对小麦萌发期的胁迫效应,选择5个耐盐性不同的春小麦品种进行复合盐胁迫处理,研究在不同浓度复合盐胁迫下,春小麦品种在发芽势、发芽率、苗高、根数、主根长和苗鲜重等指标上的差异,并采用多重比较和回归分析筛选最适复合盐萌发期处理浓度。结果表明,随着复合盐各盐分浓度升高,小麦萌发期各指标的相对耐盐系数急剧下降,且发芽势、发芽率、苗高、主根长和苗鲜重在不同浓度处理间差异极显著;但复合盐对小麦根数的影响较小,在低盐浓度下差异不显著。在Na2SO4浓度为0.05mol.L-1、NaCl浓度为0.1mol.L-1时,5个品种的发芽率、苗鲜重、苗高的相对耐盐系数在50%左右,发芽势和主根长趋近于30%,同时种子保持较高的活力,可以作为小麦萌发期耐盐鉴定的适宜复合盐胁迫浓度。  相似文献   

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