Effect of Sodium Chloride on Germination and Seedling Characters of Different Types of Rice (Oryza sativa L.)

The rice eultivars grown in the tropies and sub-tropics can be broadly categorized as aromatic small grain, local coarse grain and modern high yielding varieties (HYV). The first two categories are traditional rice, and are generally palatable. The aromatic rice has better market value than HYV rice, yet farmers are unwilling to expand its cultivation because of the low yield potential. One possibility to expand the cultivation of traditional rice is o t find stress tolerant cultivars for growing in marginal land. The salinity tolerance of nine rice cultivars representing three from each type of aromatic small grains, local coarse grains and HYV types, was analysed at germination and early seedling stage. Seeds were placed for germination and the seedlings were allowed to grow for nine days at NaCl concentrations of 0, 50, 100, 150 and 200 mM. NaCl decreased the germination index (GI), speed of germination, seedling height and seedling dry matter weight. Seedling characteristics were decreased more than GI. In general aromatic small grain type showed more salt sensitivity than the other two types. Among the nine cultivars Shakkorkhora (aromatic type) showed the least salt tolerance in relation to germination and seedling characters while the other two cultivars of the same group showed tolerance as high as the tolerant cultivars in other types. Generalization of group salt tolerance of rice, therefore, has little value from the agronomic point of view at least at early growth stage. As the number of cultivars employed in this study was only three from each type it is suggested that more cultivars be considered for the purpose of salt tolerant improvement programme of various types of rice.     

Vigour/tolerance trade‐off in cultivated sunflower (Helianthus annuus) response to salinity stress is linked to leaf elemental composition

Developing more stress‐tolerant crops will require greater knowledge of the physiological basis of stress tolerance. Here, we explore how biomass declines in response to salinity relate to leaf traits across 20 genotypes of cultivated sunflower (Helianthus annuus). Plant growth, leaf physiological traits and leaf elemental composition were assessed after 21 days of salinity treatments (0, 50, 100, 150 or 200 mM NaCl) in a greenhouse study. There was a trade‐off in performance such that vigorous genotypes, those with higher biomass at 0 mM NaCl, had both a larger absolute decrease and proportional decrease in biomass due to increased salinity. More vigorous genotypes at control were less tolerant to salinity. Contrary to expectation, genotypes with a low increase in leaf Na and decrease in K:Na were not better at maintaining biomass with increasing salinity. Rather, genotypes with a greater reduction in leaf S and K content were better at maintaining biomass at increased salinity. While we found an overall trade‐off between sunflower vigour and salt tolerance, some genotypes were more tolerant than expected. Further analysis of the traits and mechanisms underlying this trade‐off may allow us to breed these into high‐vigour genotypes in order to increase their salt tolerance.     

盐胁迫对不同基因型黄秋葵苗期生长及生理生态特征的影响

为揭示盐害下不同黄秋葵品种苗期生长的差异,以2个黄秋葵品种皇星五角(HXWJ,耐盐型)和绿新五角(LXWJ,盐敏感型)为试验材料,采用盆栽法研究不同浓度Na Cl(0,80,160 mmol/L)、不同胁迫时间(25,50 d)对黄秋葵植株苗期生长及生理生态指标的影响。结果表明:随着Na Cl浓度的提高、胁迫天数的增加,黄秋葵幼苗的株高、根长、植株鲜干质量、细胞膜稳定指数(CMSI)、K+含量,K+/Na+比呈下降的趋势;而叶片丙二醛(MDA)含量,Na+含量逐步升高;盐胁迫下黄秋葵幼苗鲜质量下降的幅度大于干质量,茎叶下降的幅度大于根系;胁迫至25 d,黄秋葵叶片和根中SOD、POD活性随Na Cl浓度增加逐步升高,胁迫至50 d,2个酶活性随Na Cl浓度增加先升高后降低;整个胁迫过程中,幼苗的株高、根长、植株鲜干质量、CMSI、K+含量,K+/Na+比含量的降幅及MDA含量的增幅均为HXWJLXWJ,表明苗期较高的干物质积累、细胞膜稳定性及K+含量是耐盐性黄秋葵品种的基本特征。     

水稻全生育期耐盐资源初步筛选

为了筛选全生育期耐盐的水稻资源,本文对500份不同来源的国内外地方品种和旱稻资源用0.3%的NaCl盐溶液进行了苗期筛选,共获得34份苗期存活率和绿叶率大于50%的材料。对上述34份材料和前人报道的121份耐盐材料用0.3%和0.5%的NaCl进行了全生育期耐盐性筛选。0.3%的NaCl共筛选到7个品种的11个全生育期耐盐存活单株,而0.5%的NaCl仅筛选到1个品种中的1个存活单株。这些材料为耐盐机理研究和耐盐育种研究提供了材料基础。     

不同盐度胁迫对芦荟生长和离子吸收分配的影响

为探索芦荟对微咸水灌溉栽培的适应性,研究了不同盐浓度对其生长和离子吸收分配的影响。结果表明,长期（120天）以含盐溶液灌溉栽培,盐浓度达200 mmol/L NaCl显著抑制芦荟生长,100 mmol/L NaCl对芦荟生长的抑制作用显著减轻,50 mmol/L NaCl不抑制芦荟生长。同时,以50 mmol/L NaCl溶液灌溉对芦荟盐分离子吸收分配影响轻微,但盐浓度达100 mmol/L NaCl对芦荟影响显著：根、茎、叶中K+含量显著下降,Na+ 、Cl-含量显著增大,K+/Na+大幅减小。X-射线能谱分析结果进一步表明,叶片贮水组织是芦荟积累盐分离子的重要部位,但100 mmol/L NaCl胁迫下芦荟根尖和叶片细胞中的离子平衡受到显著干扰。结果说明,芦荟适于用微咸水灌溉栽培,叶片贮水组织在缓解其盐胁迫中可起重要作用。     

灌浆结实期适度高温对香稻产量的影响及其机理

选用1个常规香稻品种和1个杂交香稻组合,通过人工气候室控温的方法,研究了高温处理(日均温30℃)和适温处理(日均温23℃)对产量及其构成的影响,并进一步从光合作用和碳水化合物积累的角度对其生理机制进行了分析研究。结果表明:灌浆结实期高温使新香占和优杂五山香的结实率、实粒数显著降低,虽千粒重稍有增加,但最终表现为产量极显著下降,分别比适温处理下降了22.8%和29.9%;香稻子粒灌浆中后期,高温处理显著降低了剑叶的叶绿素含量和净光合速率,使产量形成的"源"明显不足,同时子粒中可溶性糖的含量和淀粉的积累速率明显下降,使产量形成的"库"显著变弱。     

钙提高水稻耐盐性的研究

在０．５％ＮａＣｌ盐胁迫下，适当增加外界Ｃａ＾２＋浓度，可显著降低水稻体内Ｎａ＾＋含量，减少Ｎａ＾２＋由根向地上部的净运输率，并提高植株相对生长率。但Ｃａ＾２＋作用大小受介质中Ｎａ＾＋与Ｃａ＾２＋两者之比值的制约，最适Ｎａ／Ｃａ比值为２０和５０。Ｃａ＾２＋的减少（即Ｎａ／Ｃａ比值＝１０００）或过多（即Ｎａ／Ｃａ比值＝５）都导致了水稻盐害进一步加剧。钙还可以明显降低叶片和根系的质膜透性，并提高根质膜     

Growth Properties and Ion Distribution in Different Tissues of Bread Wheat Genotypes (Triticum aestivum L.) Differing in Salt Tolerance

Four bread wheat genotypes differing in salt tolerance were selected to evaluate ion distribution and growth responses with increasing salinity. Salinity was applied when the leaf 4 was fully expanded. Sodium (Na⁺), potassium (K⁺) concentrations and K⁺/Na⁺ ratio in different tissues including root, leaf‐3 blade, flag leaf sheath and flag leaf blade at three salinity levels (0, 100 and 200 mm NaCl), and also the effects of salinity on growth rate, shoot biomass and grain yield were evaluated. Salt‐tolerant genotypes (Karchia‐65 and Roshan) showed higher growth rate, grain yield and shoot biomass than salt‐sensitive ones (Qods and Shiraz). Growth rate was reduced severely in the first period (1–10 days) after salt commencements. It seems after 20 days, the major effect of salinity on shoot biomass and grain yield was due to the osmotic effect of salt, not due to Na⁺‐specific effects within the plant. Grain yield loss in salt‐tolerant genotypes was due to the decline in grain size, but the grain yield loss in salt‐sensitive ones was due to decline in grain number. Salt‐tolerant genotypes sequestered higher amounts of Na⁺ concentration in root and flag leaf sheath and maintained lower Na⁺ concentration with higher K⁺/Na⁺ ratios in flag leaf blade. This ion partitioning may be contributing to the improved salt tolerance of genotypes.     

热带水稻光合特性及氮素光合效率的差异研究

在国际水稻研究所（IRRI）农场试验条件下,选用6个不同的热带水稻材料,其中包括2个常规籼稻、2个杂交籼稻和2个新株型稻（NPT）,研究氮肥农学利用率（AE）和氮素光合效率（PNUE）及其相关叶片参数的基因型差异,并探讨了它们之间的关系。结果表明,新株型稻的净光合速率(P_n)大于常规籼稻,杂交籼稻居中。各基因型间的气孔导度(G_s)、胞间CO₂浓度(C_i)、蒸腾速率(T_r)和Ci/Gs的差异趋势不同。不同基因型叶片的氮浓度（N%）和比叶重（SLW）存在一定的差异。常规籼稻的单位叶绿素的净光合速率（P_n/Chl）较NPT低,杂交籼稻为中间类型;叶片净光合速率和单位面积含氮量（Na）之间存在显著的正相关;本研究所选用的热带杂交籼稻的PFP（氮肥偏生产力）和AE比新株型稻和常规籼稻高,两者最低的均为常规籼稻。氮素光合效率与AE间存在显著正相关,表明后期的氮素光合效率对氮肥利用率具有一定的指示和预测作用,这对于判断水稻品种氮肥利用率将具有重要的应用价值。     

淮北地区氮肥群体最高生产力水稻钾素吸收利用特征

以淮北地区有代表性的34个中熟中粳品种为试材,设置7个氮肥水平(0、150.0、187.5、225.0、262.5、300.0、337.5 kg hm~(–2)),得出各品种的最高产量,将该最高产量定义为氮肥群体最高生产力。在此基础上,明确处于顶层水平(≥10.50 t hm~(–2))、高层水平(9.75~10.50 t hm~(–2))、中层水平(9.00~9.75 t hm~(–2))和底层水平(≤9.00 t hm~(–2))水稻品种的钾素积累、分配及转运特征。结果表明,4个生产力等级水稻品种地上部植株、茎鞘和叶片的含钾率在拔节期最高;抽穗期顶层水平品种的这3个参数高于其他3个等级的品种;穗部含钾率差异不显著。随着氮肥群体生产力等级的提高,钾素总积累量增多;拔节前底层水平钾素积累量最多,两年平均为120.56 kg hm~(–2),比例占50.56%,顶层水平为最少,两年平均为108.02 kg hm~(–2),比例占35.99%;拔节至抽穗期和抽穗至成熟期顶层水平钾素阶段积累量及比例显著高于其他3个等级。移栽至拔节期,钾素积累速率为中层底层高层顶层水平,拔节后则为顶层高层中层底层水平。叶片的钾素转运量及转运率明显高于茎鞘;顶层水平叶片的钾素转运量高于其他3个等级,高层水平叶片的转运率最高;穗部增加量随生产力等级的递增而变大;抽穗到成熟期,茎鞘、叶片对穗的钾素转运贡献率表现为底层最高,中层次之,顶层最低。4个等级水稻品种籽粒生产率和百千克籽粒吸钾量差异不显著;钾素偏生产力和钾收获指数均表现为顶层高层中层底层水平。总之,氮肥群体最高生产力越高,水稻中后期植株钾素积累量及器官对钾素的吸收利用效率越显著。抽穗后保持较高的钾素吸收利用及转运效率是高产水稻品种的重要特征。     

Genetic analysis of sodium content and Na/K ratio in relation to salinity tolerance in pearl millet Pennisetum glaucum (L.) R. Br.

Genetic analysis of sodium and sodium/potassium (Na/K) ratios in leaf and stem was carried out through diallel analysis involving two tolerant, one moderately tolerant, and two sensitive genotypes as parents. Three-week-old seedlings were subjected to a critical level of salinization (17 decisiemens per meter of electrical conductivity). Leaf and stem sampling (from 5 parents and 20 hybrids arranged in a randomized block design with three replications of 10 each) was done 30 days after salinization when susceptible parents were severely effected. Predominance of non-additive gene action for stem sodium and dominance component for leaf Na/K were noticed while both additive and non-additive components played a significant role for stem Na/K. A single group of genes seems to be operative for these characters. Hybrids produced by crossing the two sensitive parents were tolerant suggesting genetic complementation and involvement of different loci in the two parents for salinity tolerance. The overall dominant nature of tolerance and the additive gene action for these salinity related characters suggested the possibility of breeding pearl millet lines through hybridization and selection to pyramid the favorable genes.     

不同浓度NaCl对两个玉米品种Na+、K+、Ca2+含量的影响

比较不同耐盐性品种在NaCl胁迫下的离子含量的差异,为耐盐玉米的筛选提供理论依据。玉米耐盐品种‘郑单958’和盐敏感品种‘齐单1号’在含0%、0.2%、0.4%、0.6%、0.8%、1.0% NaCl的砂子中生长,分别测定根、茎和叶片中Na+、K+、Ca2+含量。NaCl胁迫下,Na+、K+、Ca2+含量在两个玉米品种间、NaCl浓度间差异均达到极显著水平。NaCl胁迫下,两个玉米品种根茎叶中Na+含量均增加,根中Na+含量增加的幅度大于茎和叶,‘郑单958’根中的Na+含量高于‘齐单1号’;K+、Ca2+含量随NaCl浓度的升高而降低。高盐胁迫下,‘郑单958’根中K+含量降低的幅度大于‘齐单1号’,而茎中K+含量降低的幅度小于‘齐单1号’;‘郑单958’茎和叶片中Ca2+含量降低的幅度小于‘齐单1号’。两个玉米品种在离子含量间表现出的差异非常明显,Na+、K+、Ca2+含量可以作为玉米耐盐性鉴定和筛选指标。     

Cotton Response to Salinity and Different Potassium-Sodium Ratio in Irrigation Water

The present study was designed to investigate cotton response to different salinity levels at different K/Na ratios of irrigation water.
The salinity levels in irrigation water were 3200 and 6400 mg/1 and the control treatment had a 320 mg/L. Potassium/Sodium ratios in irrigation water were 1: 9 and 1: 4.
Some agronomic traits were studied as well as leaf water Potential (LWP), and leaf samples were taken for elemental analysis.
Statistical analysis showed that increasing total salinity of irrigation water reduced seed yield and total dry weight of cotton but not number of total or open bolls. Lower K/Na ratio (1:9) was of benificial effects on most agronomic traits.
Increasing salinity of irrigation water caused an increase in Na, but not K or Ca content of the cotton leaves; while decreasing K/Na ratio in the saline irrigation water decreased the K/Na ratio in the leaves. Lower leaf water potential was found to be associated with higher levels of both water salinity and K/Na ratio.
A strong relationships were found between cotton seed yield, LWP and K/total bases content in leaves. Ionic content relations (K/Na and K/total bases content) were found to be of a strong association with LWP.
In brief, it could be concluded that increasing K to certain extent; K/Na (1: 9) could be useful in irrigating cotton plant with high water salinity.
The benificial effects of potassium additions to diminish the salinity effects in cotton may be the consequence of improved plant water relations, as well as the status of ion relationships.     

Salinity Tolerance of Rice (Oryza sativa L.) with Reference to Endogenous and Exogenous Abscisic Acid

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.     

Effect of NaCl Salinity and Putrescine on Shoot Growth, Tissue Ion Concentration and Yield of Rice (Oryza sativa L. var. GR-3)

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.     

Unequal salt distribution in the root zone increases growth and yield of cotton

Soil salinity is often heterogeneous, yet plant response to unequal salt distribution (USD) in the root zone is seldom studied in cotton (Gossypium hirsutum L.). Our objective was to evaluate the effects of USD on growth and yield, as well as its potential application for increasing cotton production. To achieve this objective, greenhouse and field experiments were conducted. In the first experiment, potted cotton plants were grown in a split-root system in the greenhouse. Each root half was irrigated with either the same or two concentrations of NaCl. Plant biomass, leaf chlorophyll (Chl), photosynthesis (Pn) and transpiration (Tr), Na⁺ and K⁺ accumulation, as well as biological and economic yields were determined. In the second experiment, plants were grown in furrow-beds in saline fields with those grown on flat beds as controls. Root-zone salinity, yield and yield components and earliness (the percentage of the first two harvests to total harvests) were monitored. When the entire root system was exposed to the same concentration of NaCl, shoot dry weight, leaf area, plant biomass, leaf Chl, Pn and Tr were markedly reduced relative to the NaCl-free control at 2 weeks after salinity stress (WAS). Significant reductions in biological (23.6–73.8%) and economic yields (38.1–79.7%) were noticed at harvest. However, when only half of the root system was exposed to low-salinity, the inhibition effect of salinity on growth and yield was significantly reduced. Plant biomass and seed cotton yield were increased by 13 and 23.9% with 50/150 mM/mM NaCl, 40 and 44.5% with 100/300 mM/mM NaCl, and 85.7 and 127.8% with 100/500 mM/mM NaCl relative to their respective equal salt distribution (ESD) controls (100/100, 200/200, and 300/300). Unequal salt distribution also decreased concentrations of Na⁺ and increased leaf K⁺ and Chl content, K⁺/Na⁺ ratio, Pn and Tr, compared with ESD. Furrow-bed seeding induced unequal distribution of salts in the surface soil during the field experiment. Under furrow planting, soil salinity was much higher, but soil osmotic potential was much lower on the ridged part than the furrows. Yield and earliness were increased 20.8 and 5.1% by furrow seeding relative to flat seeding. These enhancements were mainly attributed to unequal distribution of salts in the root zone. Thus, specific cultural practices that induce unequal salt distribution such as furrow-bed seeding can be used to improve cotton production in saline fields.     

Soil sodicity is more detrimental than salinity for quinoa (Chenopodium quinoa Willd.): A multivariate comparison of physiological,biochemical and nutritional quality attributes

Soil salinization is a serious environmental problem worldwide. To explore the comparative effects of soil salinity and sodicity on physiological, biochemical and nutritional quality attributes of four quinoa genotypes (A1, A7, Puno, Vikinga), pot and field experiments were performed on non‐saline soil and two types of salt‐affected soils designated as SS1 (saline) and SS2 (saline‐sodic). The results of both the experiments showed similar reduction pattern in biomass (11%–44%), chlorophyll content (10%–36%), stomatal conductance (18%–32%) and grain yield (30%–47%) of four genotypes on SS2 compared with SS1. Higher sodicity level of SS2 resulted in more Na accumulation (23%–40%) and oxidative damage (12%–35% decrease in membrane stability) leading to an increase in the activities of antioxidant enzymes (SOD, POD, CAT) in all the genotypes. Grain mineral contents (except Na and Mg) were decreased more in SS2 than SS1. Multivariate analysis revealed that grain Na content has negative correlation with all the nutritional quality attributes except Mg and fibre contents. Genotypes A1 and A7 were more salt tolerant with better grain nutritional quality than Puno and Vikinga. It is concluded that soil sodicity is more detrimental than salinity, and quinoa genotypes A1 and A7 are better than Puno and Vikinga for cultivation on saline and saline‐sodic soils.     

盐胁迫下水稻叶绿素荧光特性与离子积累的相关性分析

以4个北方常规粳稻品种为材料,于孕穗期施加80 mmol/L的NaCl胁迫测定了水稻叶片叶绿素荧光参数及体内离子含量的变化,以揭示盐胁迫下水稻离子积累与叶绿素荧光特性的相关性。结果表明盐胁迫下水稻叶片最大荧光(Fm)、最大光化学量子效率(Fv/Fm)、光系统Ⅱ的实际光合效率(PhiPSⅡ)、表观光合量子传递效率(ETR)和光化学猝灭(qP)均呈下降趋势最小初始荧光(Fo)和非光化学猝灭(qN)呈升高趋势。盐胁迫导致水稻体内Na⁺、Cl^-积累显著增加,K+积累显著下降,SO₄^2-、PO₄^3-和NO3-含量较对照差异不显著。盐胁迫下水稻叶绿素荧光参数与Na⁺、Cl^-和SO₄^2-含量呈显著负相关,与K+和PO₄^3-含量呈显著正相关,与NO3-含量相关性不显著。以上结果表明水稻体内有害离子在盐胁迫下会过量积累这是导致水稻叶片光合结构破坏和光合作用效率下降的重要原因。     

水稻耐碱突变体ACR78在苏打盐碱胁迫下的离子吸收特性

利用盆栽方法,比较研究了盐碱胁迫下水稻耐碱突变体(ACR78)及其野生型植株体内K+、Na+、Ca2+、Mg2+、Fe2+和Zn2+含量的变化.结果表明,盐碱胁迫下,ACR78全株Na+总含量比野生型减少2.9%,显著低于野生型.同时,其K+、Zn2+和Mg2+含量比野生型分别增加18.3%,89.7%和4.9%(P<0.05),全株K+/Na+比值(0.16)显著高于野生型(0.13).从器官水平看,ACR78茎中+>/Na+比值极显著高于野生型,约为野生型的1.4倍.ACR78根和茎中Na+含量显著低于野生型(14.0%和5.9%),其茎中K+含量比野生型增加32.3%,根和叶中无显著性差异.ACR78根和茎中Zn2+含量分别比野生型增加44.2%和202.7%,Mg2+含量在器官中的分配规律与Na+相反.说明ACR78可显著抑制Na+的吸收,并对K+、Zn2+和Mg2+具有较强的选择性吸收能力.