Al3+对大豆根边缘细胞释放与活性的影响

以两个大豆 [Glycine max (L.) Merr.] 品种（耐铝性大豆浙春2号和铝敏感性大豆华春18）的边缘细胞为材料,比较研究了Al3+对根尖原位边缘细胞释放以及对离体边缘细胞的毒害作用。结果显示,0、100、200 μmol/L Al3+处理后,浙春2号和华春18的根尖边缘细胞在水中均易分散,华春18的边缘细胞在300 μmol/L的Al3+处理时已聚集成团不易分散,而浙春2号的边缘细胞在400 μmol/LAl3+处理时才不易分散。Al3+对离体边缘细胞有明显的毒害作用,100 μmol/L Al3+处理1～ 6 h就表现出细胞死亡症状,毒害作用最大时出现在6 h之后,其中Al3+对华春18的毒害作用略高于浙春2号。系列浓度Al3+ （0、100、200、300、400 μmol/L Al3+）处理,100 mol/ L Al3+处理的离体边缘细胞存活率已出现较大幅度的下降,至400 mol/L Al3+处理时,浙春2号和华春18的相对存活率分别只有对照的45.9%和39.0%。 说明外界Al3+浓度升高不仅影响边缘细胞的释放,而且显著降低离体边缘细胞的存活率,毒害作用最大时出现在6 h之后。大豆品种间细胞对Al3+的反应存在一定差异,随时间变化,差异最大时在6 h。     

红豇豆根缘细胞对铝胁迫的响应

以红豇豆(Vigna.ungniculata.ssp.sesquipedalis.cv.chuangfeng)为材料,采用悬空气培法,研究红豇豆根缘细胞产生的数目、活性及对铝胁迫的响应。结果表明,红豇豆的边缘细胞数目先随着根的伸长而迅速增加,到根长为10mm时达到最多,约为5300个;随后,边缘细胞数目稍有减少,且较为稳定。边缘细胞的存活率较高,都大于85%,随着红豇豆根长的伸长,边缘细胞的活性逐渐增高。根冠果胶甲基酯酶(PME)的活性随着根的伸长而减小,表明边缘细胞游离与根冠PME活性有着密切的相关性。离体边缘细胞的存活率随着Al3+处理浓度和处理时间的增加而降低。不同浓度Al3+液处理对相同根长红豇豆的根冠PME酶活性没有显著的影响。     

荞麦根缘细胞的发育及脱落后对铝毒的响应

采用悬空气培法,研究了荞麦根缘细胞发育过程的形态、活性变化和脱落后对铝(Al3+)毒的响应。结果显示,荞麦根缘细胞绝大多数呈细杆状,少数呈弯曲的长条型。根长25.mm时,根缘细胞中活细胞的比率最大(约94%);果胶甲基酯酶(PME)在根生长至5.mm时,活性最大,此后随着根的伸长,PME活性迅速下降,根长大于25mm时PME活性稳定在最大值的40%。脱离根尖的根缘细胞经50mol/L.Al3+处理,随着处理时间延长,存活率大幅度下降,处理后48.h时,存活率只有5%。铝毒加速离体根缘细胞的死亡。     

水稻根尖边缘细胞对铁毒的形态生理响应

以水稻(Oryza sativa L.)品种Azucena（铁耐性）和IR64（铁敏感）为材料,研究了Fe2+毒胁迫下附着于根尖边缘细胞(即原位边缘细胞)的数目、存活率,根尖细胞形态结构、根尖保护酶活性的变化。结果显示,Fe2+ 毒对根边缘细胞的产生有抑制作用。相对于敏感性品种而言,一定浓度Fe2+(100~200 μmol/L)有利于耐性品种边缘细胞的产生;Fe2+ 毒对边缘细胞有致死效应,随Fe2+浓度的提升,边缘细胞的存活率呈下降趋势,根尖外围细胞壁增厚,并出现细胞程序性死亡特征(敏感性品种)。同时,Fe2+ 毒对根尖保护酶活性有一定的影响,200~400 μmol/L Fe2+处理下,耐性品种POD、CAT、SOD活性都超过对照;敏感品种只有SOD活性超过对照。说明Fe2+毒胁迫下,水稻根尖通过增加边缘细胞数目、提高细胞拒铁作用,维持较高水平的POD、CAT和SOD活性来对抗Fe2+毒,缓解铁毒害。     

镉胁迫对水稻幼苗生长和根尖细胞分裂的影响

研究了镉(Cd)对水稻幼苗生长、根尖细胞有丝分裂及染色体畸变的影响。结果表明,随着Cd浓度增加和处理时间延长,水稻幼苗根的生长及根尖细胞有丝分裂指数明显降低。Cd使有丝分裂中期细胞所占比例相对增加,前期、后期、末期细胞相对减少。Cd能诱导染色体产生多种类型的畸变,染色体畸变率随着Cd处理浓度的增加和处理时间的延长而升高,呈现明显的剂量-效应和时间-效应关系。1～10μmol L-1Cd胁迫24 h后,水稻根尖畸变主要有C-有丝分裂、染色体桥,占总畸变率的32.64%～78.29%;25～200μmol L-1Cd胁迫24～72 h后,水稻根尖细胞中染色体粘连、断片和微核占较大比例,占总畸变率的76.44%～93.96%。研究表明,Cd对水稻根尖分生细胞有丝分裂具有阻滞作用,并诱发染色体畸变率的显著升高。     

Cd~(2+)胁迫下多年生黑麦草的生长与生理响应

为检验多年生黑麦草对重金属Cd2+的修复潜力,本文研究了多年生黑麦草对重金属Cd2+的积累特性和生长、生理响应,采用水培法对多年生黑麦草进行0、5、10、20mg·L-1重金属Cd2+胁迫,测定了地上部和地下部的生物量、Cd浓度。结果表明,处理6d后,多年生黑麦草的生长受Cd2+显著抑制,地下部、地上部的Cd2+浓度均随着处理浓度的增加而显著升高,多年生黑麦草对Cd2+具有超量积累能力。5mg·L-1Cd2+处理6d后,多年生黑麦草的地下部、地上部生物量和根冠比分别较对照显著下降了36.83%、12.17%和27.59%,叶片的净光合速率在5mg·L-1Cd2+处理6d后较对照显著下降了23.38%,而其他的气体交换参数、光合色素含量和PSⅡ最大、潜在光化学效率均未受到Cd2+的影响;当光合有效辐射超过580μmol·m-2·s-1时,5mg·L-1Cd2+处理下的实际光化学效率和相对电子传递速率均显著低于对照,Cd2+对多年生黑麦草光反应系统电子传递的抑制程度随着光合有效辐射的升高而增加;当辐射强度达到1 465μmol·m-2·s-1时,相对电子传递速率较对照显著下降了15.46%。5mg·L-1Cd2+胁迫下,多年生黑麦草叶片PSⅡ调节性能量耗散始终显著高于对照,减轻了过多激发能对光合机构的伤害。5mg·L-1Cd2+胁迫下,多年生黑麦草叶片和根系的超氧化物歧化酶、抗坏血酸过氧化物酶的活性被抑制,过氧化氢酶的活性被促进,丙二醛的含量显著提高。净光合速率、相对电子传递速率及SOD、APX活性可做为检验Cd2+对多年生黑麦草毒害的生理指标。本研究得到的结论可为在草坪草中选育重金属污染的修复植物提供参考。     

水稻根尖铁的积累及附着形态研究

以铁毒耐性水稻(Oryza sativa L.)品种"9308"为材料, 利用火焰原子吸收光谱法和化学浸提法研究0～10 mm段水稻根尖铁的积累及附着形态.结果表明: 高Fe2+(400 -mol·L-1)胁迫下, 0～2 mm段水稻根尖铁含量最高; 随着Fe2+浓度的升高, 根边缘细胞铁含量也明显增大; 初生根上不同形态铁的含量为铁锰氧化物态>残渣态>有机态>可交换态>碳酸盐态.以上结果表明, 水稻根尖0～2 mm段是过量铁的主要作用位点, 铁的附着形态以紧密结合态为主, 包围在外的根边缘细胞能固定过量铁.     

低pH和铝毒对荞麦根边缘细胞特性的交互作用研究

采用悬空气培法,研究低pH(3.5、4.5、5.5)和铝毒(0、50、100μmolL-1)及其交互作用对荞麦根长、根边缘细胞活性及其分泌的黏液层厚度的影响。处理12h,Al3+浓度由50μmolL-1增至100μmolL-1时,pH3.5的根伸长量分别降低18.6%和31.9%,pH4.5时分别降低18.9%和26.8%,pH5.5时各降低8.5%。处理24h的根伸长量变化与12h类似。pH降低至3.5时,边缘细胞的活性下降28.6%,黏液层厚度无明显变化。Al3+浓度升高至100μmolL-1时,黏液层增厚64.6%,而边缘细胞活性变化不大。pH3.5与100μmolL-1Al3+的处理,边缘细胞活性最低,黏液层厚度最大,两者间存在极显著的交互作用。可见低pH加剧铝毒发生,外围黏液层产生可以减轻Al3+对边缘细胞的伤害。     

硼对豌豆根尖铝毒的影响

研究了B(0、 100、 1000μmol/L)对豌豆根尖Al和胼胝质含量的影响,以揭示B是否能减轻Al胁迫.发现:Al浓度100 μmol/L时,浓度100 μmol/L B处理的根苏木精染色颜色较不加B处理浅.Al浓度100 μmol/L和500μmol/L时,100μmol/L B处理的豌豆0～0.5 cm和0.5～1 cm根段的Al含量均比未加B处理有明显降低的趋势;高B处理(1000 μmol/L)均引起根段的Al含量高于不加B处理.Al浓度100 μmol/L时,加B处理后豌豆0～0.5 cm根段胼胝质含量显著低于不加B处理.结果表明:适量B可以减轻豌豆根尖Al毒.     

不同浓度镉胁迫对玉米幼苗光合作用、脂质过氧化和抗氧化酶活性的影响

以玉米为材料,通过营养液培养试验,研究浓度为5~100 μmol/L的镉胁迫后不同时间内,植株体内活性氧代谢及其抗氧化酶活性的变化特征,探讨镉胁迫导致植物体内活性氧自由基累积的原因及不同程度镉胁迫对植物体内活性氧代谢的影响。随着加镉量的增加,玉米地上部生物量明显降低,而根部生物量未表现出差异。镉处理降低了叶片光合作用速率,高镉处理的影响较早。镉处理4d后,5、20、和100 mol/L Cd2+浓度处理玉米叶片Fv/Fm减小,PSII系统的原初光能转换效率下降,但比光合作用速率下降的时间要晚;镉处理7d的叶片中丙二醛（MDA）含量还没有受到明显影响,但20和100 μmol/L Cd2+处理4d后,根系膜质过氧化增强,MDA含量升高。随着镉浓度升高,处理时间延长,活性氧酶清除系统包括超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）等酶活性明显增加,受到镉胁迫诱导,高浓度镉处理该现象出现更早。本文试验结果表明,镉胁迫下植物体内活性氧形成增多,诱导活性氧酶清除系统活性升高,其中一个重要原因是与CO2同化受到限制有关。     

红壤交换性钙、镁和钾的分布及施肥对其影响

A leaching experiment was Carried out with repacked soil columns in laboratory to study the leaching process of a red soil derived from sandstone as affected by various fertilization practices.The treatments were CK(as a control),CaCO3,CaSO4,MgCO3,Ca(H2PO4)2,Urea,KCl,Multiple(a mixture of the above mentioned fertilizers) and KNO3,The fertilizers were added to the bare surface of the soil columns,and then the columns were leached with 120 mL deionized water daily through perstaltic pumps over a period of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles ,i.o.,of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles,I.e.0-5cm,5-10cm,10-20cm,20-40cm,and 40-60cm,The results showed when applying Ca,Mg,and K to the bare surface of the soil columns,exchangeable Ca^2 ,Mg^2 ,and K^ in the upper layer of the soil profile increased correspondingly,with an extent depending mainly on the application rates of Ca,Mg,and K and showing a downward trend,CaCO3,CaSO4,MgCO3,and Ca(H2PO4)2 treatments had scarcely and effect on movement of exchangeable K^ ,while CaCO3,and CaSO4 treatments singnificantly promoted the downward movement of exchangealble Mg^2 although these two treatments had no obvious effect on leaching losses of Mg,The fact that under Urea treatment,exchangeable Ca^2 and Mg^2 ,were higher as compared to CK treatment showed urea could prevent leaching of exchangeable Ca^2 and Mg^2 ,the obvious downward movement of exchangeable Ca^2 and Mg^2 was noticed in KCl treatment ,In Multiple treatment,the downward movement of exchangeable Ca^2 and Mg^2 was evident,while that of K^ was less evident,Application of KNO3 strongly promoted the downward movement of exchangeable Ca^2 and Mg^2 in the soil profile.     

Response of plant yield and leaf pigments to saline conditions: Effectiveness of different rootstocks in melon plants (Cucumis melo L.)

Two varieties of Cucumis melo (Resisto and Arava) were grafted onto three hybrids of Cucurbita maxima and Cucurbita moschata cultivars (Shintoza, RS-841 and Kamel). Ungrafted Cucumis melo var. Resisto and var. Arava plants were used as controls. Plants were grown under controlled greenhouse conditions and were constantly fertilized with macro- and micronutrients, supplied with irrigation water rich in Na⁺ and Cl^- Contents of chlorophylls a and b, carotene pigments, Cl^- and total and soluble Na⁺ and K⁺ ions were measured in all the scion parts of the plants. The results showed that grafted plants exhibited differences in the leaf content of Na+ and especially Cl^- in comparison with ungrafted plants. In addition, yield as well as leaf pigments appeared to be good indicators of Cl^- levels in scion parts. It is assumed that grafted plants developed various mechanisms to avoid physiological damage caused by the excessive accumulation of these ions in leaf, including the exclusion of Cl^- ion and/or decrease in Cl^- absorption by the roots and the replacement or substitution of total K⁺ by total Na⁺ in the foliar parts.     

水稻土Fe2+氧化耦合硝酸根异化还原成铵(DNRA)及其对氧气存在和碳源添加的响应

以江苏常熟和湖南桃源水稻土为研究对象,通过室内15N示踪实验研究水稻土中Fe²⁺氧化耦合硝酸根异化还原成铵(Dissimilatory nitrate reduction to ammonium,DNRA)过程及其对氧气存在和碳源添加的响应。结果表明,两种水稻土中均存在Fe²⁺氧化耦合DNRA过程,常熟和桃源水稻土中DNRA的速率分别为0.38±0.15和0.36±0.21nmol·g^-1·h^-1(以N计),当体系中Fe²⁺浓度为500μmol·L^-1时,DNRA速率有所提升但并不显著,当Fe²⁺浓度为800μmol·L^-1时,DNRA速率提升显著(P <0.05),分别提升至2.35±0.30和0.81±0.22 nmol·g^-1·h^-1。在800μmol·L^-1Fe²⁺浓度下,常熟水稻土中Fe²⁺氧化耦合DNRA的速率显著(P <0.05)高于桃源水稻土,与两种水稻土中nrfA功能基因丰度的高低一致。在氧气存在和碳源添加的响应实验中,单一氧气处理、单一乳酸处理及氧气乳酸联合处理均显著(P <0.05)促进桃源水稻土Fe²⁺氧化耦合DNRA过程速率,而在常熟水稻土中,800μmol·L^-1Fe²⁺浓度下,单一乳酸及乳酸氧气联合处理显著(P <0.05)抑制Fe²⁺氧化耦合DNRA过程速率。以上研究表明,两种水稻土中均存在Fe²⁺氧化耦合DNRA过程,氧气和乳酸的单独、联合作用可以影响Fe²⁺耦合DNRA过程,但具体影响因土壤而异。未来研究还应纳入更多土壤样本,综合考虑环境因子和土壤性质对Fe²⁺氧化耦合DNRA过程的影响。     

Negative correlation between the ratio of K+ to Na+ and proline accumulation in tobacco suspension cells

Abstract

The concentrations of K⁺, Na⁺, and proline and the ratio of K⁺ to Na⁺ (K⁺ / Na⁺) were analyzed in NaCl-unadapted and NaCl-adapted tobacco (Nicotiana tabacum) cells in suspension culture. At 3 to 5 d after inoculation, the NaCl-unadapted cells cultured in 100 mmol L^?1 NaCl saline culture medium (Na100 medium) accumulated 28.7 mmol L^?1 proline with a low ratio of K⁺ to Na⁺ (= 2.8) and the NaCl-adapted cells cultured in the Na100 medium contained 6.28 mmol L^?1 proline with a high K⁺ / Na⁺ ratio (≧ 7.5). The contents of amino acids for the NaCl-adapted cells in the Na100 medium were similar to those for the NaCl-unadapted cells in a modified LS medium (standard medium). At 14 d after inoculation, the NaCl-unadapted cells in the Na100 medium contained 4.77 mmol L^?1 proline and restored the K⁺ / Na⁺ ratio from 2.8 to 6.2. These results indicate the presence of a negative correlation between the K⁺ / Na⁺ ratio and proline accumulation and suggest that a balance between the K⁺ / Na⁺ ratio and proline accumulation may be the factor involved in determining the salt tolerance of plant cells.     

Microbial community response to nitrogen deposition in northern forest ecosystems

The productivity of temperate forests is often limited by soil N availability, suggesting that elevated atmospheric N deposition could increase ecosystem C storage. However, the magnitude of this increase is dependent on rates of soil organic matter formation as well as rates of plant production. Nonetheless, we have a limited understanding of the potential for atmospheric N deposition to alter microbial activity in soil, and hence rates of soil organic matter formation. Because high levels of inorganic N suppress lignin oxidation by white rot basidiomycetes and generally enhance cellulose hydrolysis, we hypothesized that atmospheric N deposition would alter microbial decomposition in a manner that was consistent with changes in enzyme activity and shift decomposition from fungi to less efficient bacteria. To test our idea, we experimentally manipulated atmospheric N deposition (0, 30 and 80 kg NO₃⁻-N) in three northern temperate forests (black oak/white oak (BOWO), sugar maple/red oak (SMRO), and sugar maple/basswood (SMBW)). After one year, we measured the activity of ligninolytic and cellulolytic soil enzymes, and traced the fate of lignin and cellulose breakdown products (¹³C-vanillin, catechol and cellobiose).In the BOWO ecosystem, the highest level of N deposition tended to reduce phenol oxidase activity (131±13 versus 104±5 μmol h⁻¹ g⁻¹) and peroxidase activity (210±26 versus 190±21 μmol h⁻¹ g⁻¹) and it reduced ¹³C-vanillin and ¹³C-catechol degradation and the incorporation of ¹³C into fungal phospholipids (p<0.05). Conversely, in the SMRO and SMBW ecosystems, N deposition tended to increase phenol oxidase and peroxidase activities and increased vanillin and catechol degradation and the incorporation of isotope into fungal phospholipids (p<0.05). We observed no effect of experimental N deposition on the degradation of ¹³C-cellulose, although cellulase activity showed a small and marginally significant increase (p<0.10). The ecosystem-specific response of microbial activity and soil C cycling to experimental N addition indicates that accurate prediction of soil C storage requires a better understanding of the physiological response of microbial communities to atmospheric N deposition.     

Natural N abundances in a tallgrass prairie ecosystem exposed to 8-y of elevated atmospheric CO2

After 8-y of elevated CO₂, we previously detected greater amounts of total soil nitrogen, suggesting that rates of ecosystem N flux into or out of tallgrass prairie had been altered. Denitrification and associative N fixation rates are the two primary biological processes that are known to control N loss and accumulation in tallgrass prairie soil. Therefore, our objective was to assess the natural abundance of plant and soil ¹⁵N isotopes as a cumulative index of potential change in efflux or influx of N into and out of the tallgrass prairie after 8-y of exposure to elevated CO₂. Aboveground plant delta ¹⁵N values of Andropogon gerardii were close to zero and more positive as a result of elevated CO₂, but whole-soil values at the 5-30 cm depth were significantly reduced (6.8 vs 7.3; P<0.05) under elevated CO₂-chamber (EC) relative to ambient CO₂- chamber (AC). Total, aboveground plant biomass, root-in-growth, extractable N, microbial biomass N, and soil pools collectively exhibited a range of delta ¹⁵N values from −2.8 to 7.3. Measurements of surface soil ¹⁵N indicate that a change in N inputs and outputs has occurred as a result of elevated atmospheric CO₂. In addition to possible changes in denitrification and N₂ fixation, other sources of N such as the re-translocation of N to the surface from deeper soil layers are needed to explain how soil N accrues in surface soils as a consequence of elevated CO₂. Our results support the notion that C accrual may promote N accrual, possibly driven by high plant and microbial N demand amplified by soil N limitation.     

Fate of C- and N-labelled rhizodeposition of Lolium perenne as function of the distance to the root surface

A greenhouse rhizobox experiment was carried out to quantify the incorporation of ¹³C- and ¹⁵N-labelled rhizodeposits into different soil pools, especially into the rhizosphere microbial biomass, with increasing distances to the root surface of Lolium perenne. Five layers were analysed over 0-4.2 mm distance to an artificial root surface. C and N derived from rhizodeposition were 4.2% of total C and 2.8% of total N in soil at 0-1.0 mm distance and decreased rapidly with increasing distance. Microbial biomass C and N increased significantly towards the roots. At 0-1.0 mm distance microbial biomass C and N accounted for 66% and 29% of C and N derived from rhizodeposition, respectively. These percentages declined with increasing distance to the roots, but were still traceable up to 4.2 mm distance. Only small amounts of root released C and N were found in the 0.05 M K₂SO₄-extractable fraction. Extractable C and N derived from rhizodeposition varied around means of 4% of total C and N derived from rhizodeposition and increased only marginally with increasing distance to the roots. C derived from rhizodeposition in the non-extractable soil organic matter increased from 65 to 89% of total C derived from rhizodeposition at 0-3.4 mm distance. Conversely, microbial biomass C derived from rhizodeposition decreased from 33 to 4%. N derived from rhizodeposition in the non-extractable soil organic matter increased from 61 to 79% of total N derived from rhizodeposition at 0-2.6 mm distance, followed by a decline to roughly 55% in the two outer layers. Microbial biomass N decreased from 37 to 16% at 0-2.6 mm distance, followed by an increase to roughly 41% in the two outer layers. The C/N ratio of total C and N derived from rhizodeposition as well as that of extractable C and N derived from rhizodeposition increased with increasing distance to the roots to values above 30. In contrast, the C/N ratio of incorporated rhizodeposition C and N into the microbial biomass decreased to values less than 5 at 2.6-4.2 mm distance. The data indicate differential microbial response to C and N derived from rhizodeposition at a high spatial resolution from the root surface. The turnover of C and N derived from rhizodeposition in the rhizosphere as a function of the distance to the root surface is discussed.     

Differential Responses of Conventional and Bt-Transgenic Cotton to Potassium Deficiency

Bacillus thuringensis (Bt) transgenic (insect-resistant) cotton cultivars senesce prematurely under potassium (K⁺) deficiency, more often than conventional cultivars, in the North China Plain. To verify if Bt-transgenic cotton was more susceptible to K⁺ deficit, two transgenic cultivars, ‘CCRI 41’ and ‘DP 99B’, and two conventional cultivars, ‘CCRI 35’ and ‘CCRI 36’, selected from widely used cultivars in China, were used in a seedling hydroponic study. The culture solution K⁺ concentration was 0.5 mM for high K⁺ and 0.02 mM for low K⁺ conditions. Seedlings of all four cultivars accumulated more dry matter and K⁺ when grown at high K⁺ than low K⁺ conditions. However, under low K⁺ condition, the dry weight and K⁺ content of Bt-transgenic cultivars CCRI 41 and DP 99B were lower than those of the conventional cultivars CCRI 36 and CCRI 35. The results indicated that Bt-transgenic cultivars CCRI 41 and DP 99B were more sensitive to K⁺ deficiency than conventional cultivars CCRI 36 and CCRI 35, which could be the reason for premature senescence symptoms observed from fields of Bt-transgenic cotton under K⁺ deficiency. Seedlings of all four cultivars had a higher K⁺ use efficiency (KUE) under low K⁺ than high K⁺ conditions, but the KUE did not account for the differential responses between Bt-transgenic and conventional cultivars at the low K⁺ concentration. The K⁺ depletion results did not reveal the mechanism for the above differential responses in V_max and K_m of the seedlings either. Further experiments with more cultivars are needed to clarify the differential mechanisms in these genotypes.     

Differential Response to Salt Stress Within and Among Iranian Melilotus Species

This paper explores the salt-tolerance response of Melilotus species, a forage legume, based on tolerance/susceptibility indices, leaf water relations, leaf/root ion concentrations and multivariate (factor and function discriminate) analyses. In a greenhouse experiment, salinity-susceptibility of 12 accessions of Melilotus (M. albus, M. indicus, M. officinalis) in addition, two controls (alfalfa and Persian clover) were evaluated at 0 mM, 100 mM, 200 mM, and 300 mM of sodium chloride (NaCl). The experiment was conducted in a split plot design with two replications. Stress tolerance score (STS) was calculated based on tolerance/susceptibility indices. Salt-tolerant accessions were identified. An extracted bi-plot based on factor analysis confirmed the results of tolerance/susceptibility indices. There were significant correlations between STS and multivariate statistics. Root potassium cation (K⁺) concentration was higher in Melilotus species than the control species in all the salinity treatments. STS, root K⁺ concentration, leaf turgidity, and leaf succulence characteristics can be used for screening salinity-tolerance in Melilotus accessions. In all treatments, M. officinalis, M. indicus, and M. albus were salinity-tolerant species in descending order.

Abbreviations: Total biomass yield under control (Yp) and stress (Ys) mediums, geometric mean productivity (GMP), leaf area (LA), leaf tissue density (LTD), linear regression coefficient (b), mean productivity (MP), relative water content (RWC%), Succulence (S), specific leaf area (SLA), stress susceptibility index (SSI), stress tolerance index (STI), tolerance (TOL), water content at saturation (WCS), water saturation deficit (WSD), sodium chloride (NaCl), potassium cation (K⁺), sodium cation (Na⁺), analysis of variance (ANOVA), least significant difference (LSD), alfalfa control accession (CHA), Persian clover control accession (CHC), coefficient of variation (CV), statistics of factor (F) and discriminate function (D)