RESPONSE OF ORNAMENTAL SUNFLOWER CULTIVARS ‘SUNBEAM’ AND ‘MOONBRIGHT’ TO IRRIGATION WITH SALINE WASTEWATERS

To explore the possibility that saline wastewaters may be used to grow commercially acceptable floriculture crops, a study was initiated to determine the effects of salinity on two pollen-free cultivars of ornamental sunflower (Helianthus annuus L.). ‘Moonbright’ and ‘Sunbeam’ were grown in greenhouse sand cultures irrigated with waters prepared to simulate wastewaters commonly present in two inland valley regions of California: 1) San Joaquin Valley (SJV) where saline-sodic drainage waters are dominated by sodium (Na⁺) and sulfate (SO ^2? ₄ ) and 2) Coachella Valley (CV) where major ions in tailwaters are Na⁺, chloride (Cl^?), SO ^2? ₄ , magnesium (Mg²⁺), calcium (Ca²⁺), predominating in that order. Ten-day-old seedlings were subjected to five salinity treatments of each water composition, each replicated three times. Electrical conductivities (EC) of the irrigation waters were 2.5, 5, 10, 15, and 20 dS·m^?1. Flowering stems were harvested when about 75% of the ray flowers were nearly horizontal. Stem length and fresh weight, flower and stem diameter were measured. Mineral ion concentrations in upper and lower stems, upper and lower leaves were determined. Sodium was excluded from the young tissues in the upper portions of the shoot and retained in the basal stem tissue. Inasmuch as sunflower is also a strong potassium (K)-accumulator, K⁺/Na⁺ selectivity coefficients were unusually high in the younger shoot organs. Despite a five-fold increase in substrate Ca²⁺ in both solutions, shoot-Ca decreased as salinity increased and this cation was retained in the older leaves. A few of the lower leaves of plants irrigated with ICV waters at EC = 10 dS·m^?1 and higher, exhibited necrotic margins which were undoubtedly caused by high concentrations of Cl^? in the tissues. Flowering stems produced in all treatments met florist quality standards in terms of diameters for stems (0.5 to 1.5 cm) and blooms (8 to 15 cm). Across treatments, stem lengths ranged from 60 to 175 cm. Both ornamental sunflower cultivars proved to be good candidates for production of marketable flowering stems using moderately saline wastewaters.     

Effect of dimethylarsenic acid (DMAA) on growth,tissue arsenic,and photosynthesis of rice plants

The effect of dimethylarsenic acid (DMAA) applied to the root on arsenic (As) uptake and concentration, net photosynthesis (Pn), and growth parameters of rice (Oryza sativa L. cv. ‘Mercury') plants was studied. The experiment consisted of four treatments (0, 0.2, 0.8, and 1.6 mg As/L) with four replications in a completely randomized design. The DMAA was applied in nutrient solution as its sodium salt. The solution culture was changed every four days to avoid changes in the As chemical form. Arsenic uptake and concentration in shoot and root increased upon increased DMAA concentration in solution. Upon uptake, DMAA was readily translocated to the shoot. At the two higher rates of DMAA application (0.8 and 1.6 mg As/L), Pn and photosynthetic capacity were significantly decreased in response to tissue As concentration. Leaf area and dry matter production were also significantly reduced at the two higher rates of DMAA. At the lower rate (0.2 mg As/L) of DMAA application, there was no significant reduction in Pn or growth. Dimethylarsenic acid application did not affect nutrient allocation within the rice plant at concentration levels used in this study.     

黄河三盛公水利枢纽三角区盐碱化研究

以黄河内蒙段河套灌区黄河水利枢纽拦河闸与三盛公水电站三角区如何实施节水灌溉的同时又要防治土壤盐碱化为双重目标,以当地主要经济作物向日葵为田间试验作物,通过在不同盐碱化土壤上进行的节水灌溉试验,分析了不同水分、盐分双重胁迫条件下对向日葵生长发育的影响,并对不同盐碱化土壤向日葵的主要生理发育指标进行了统计分析。结果表明,盐碱土抑制种籽的萌发,盐碱土程度越重,抑制作用越明显;随含盐量的增加,向日葵叶、秆的干物质积累呈下降趋势,相应的产量也呈下降趋势。     

Improvement in the Adaptation of Lygeum Spartum L. to Salinity In the Presence of Calcium

Lygeum spartum L. has been recently introduced in areas where salinity is high in soils. However, there are no studies about the physiological response of these plants to salt excess. The effect of sodium chloride (NaCl) on plant growth and water status was studied. Also, the effect of calcium (Ca) addition to salinity conditions was analyzed because of the coexistence of salinity and calcareous soils. Dry weight (DW), transpiration, and osmotic potential (Ψπ) decreased with elevated NaCl and were restored with Ca²⁺, whereas moderate salinity had no effect. Fresh weight (FW), water potential (Ψω), and root hydraulic conductance (L ₀) decreased with salinity; Ca²⁺ supply had an ameliorative effect at moderate salinity. Sodium (Na⁺) increased in leaf sap at high levels of NaCl and was decreased by Ca²⁺. Lygeum spartum showed a resistance to moderate salinity, but the effect of Ca²⁺ depends on salinity intensity. Thus, the role of Ca²⁺ in the tolerance to salinity was emphasized.     

Interaction between Salinity and Original Habitat during Germination of the Annual Seashore Halophyte Cakile Maritima

The impact of salinity (0–400 mM NaCl) on the germination of four Tunisian accessions (Tabarka, Mahdia, Sfax, and Jerba) of the halophyte Cakile maritima was assessed. Moderate salinity (50–150 mM NaCl) slightly inhibited the germination of Sfax, Mahdia, and Jerba seeds, since more than 75% of the sown seeds germinated. Salt adverse impact was more pronounced in Tabarka seeds, which showed significantly less germination capacity, even under salt‐free conditions (40%). Although increasing salinity drastically inhibited the germination in Tabarka, Sfax was the most tolerant accession, especially at 200–300 mM sodium chloride (NaCl). Assessing germination kinetics using a mathematical model indicated that high salinity impaired and delayed the germination process. Such an effect resulted from the combination of osmotic and toxic components, especially at the greatest concentrations (300–400 mM NaCl). These findings point out that the successful establishment of this halophyte at the earliest ontogeny stages is both accession‐ and salt‐dependent.     

温度和盐度对中华原钩虾幼体孵化、存活及生长的影响

采用室内受控实验方法测定了不同温度(15,20,25和30℃)和盐度(盐度5,10,15,20,25,30和35)以及温度和盐度交互作用对中华原钩虾幼体孵化、存活及生长的影响。结果表明,中华原钩虾幼体孵化的数量受水温影响显著(P<0.05),20℃幼体孵化率最高,平均每只亲体孵化幼体30.67个。水温对幼体生长的影响差异十分显著(P<0.01),15~25℃范围内,幼体的日增长和特定生长率随水温升高而增加,水温25℃时达到最大值,平均日增长体长为0.23 mm/d、体质量平均日增长体质量为0.20 mg/d,特定生长率体长为6.40%/d、体质量特定生长率为15.79%/d;当水温高于25℃,钩虾的日增长和特定生长率降低。根据相关性方程式推算其最适孵化温度为21.50℃,最适生长温度为20~25℃。中华原钩虾幼体的存活率受温度的影响差异不显著(P>0.05),20℃钩虾幼体存活率最高,为98%,30℃存活率最低,为87.67%。盐度对中华原钩虾孵化幼体数量、存活率及幼体生长的影响差异不显著(P>0.05)。温度和盐度交互作用结果表明,中华原钩虾对盐度有较好的适应能力,温度对中华原钩虾种群发展的影响要大于盐度的影响。     

三疣梭子蟹(Portunus trituberculatus)几丁质酶PtCht3基因克隆鉴定及表达分析

为初步研究三疣梭子蟹(Portunus trituberculatus)几丁质酶PtCht3的生物学功能,利用特异性引物扩增和SMARTTM RACE技术克隆获得三疣梭子蟹PtCht3基因全长cDNA序列,并对该序列进行分析.结果显示,三疣梭子蟹PtCht3基因全长为1409 bp,对PtCht3基因序列推导出的氨基酸序列进行分析可知,该基因编码由394个氨基酸组成的蛋白质,预测分子量为43.67 kDa,理论等电点为4.80.PtCht3蛋白亲水性总平均数为-0.097,属于稳定蛋白.同源性和系统进化分析发现,PtCht3与日本仿长额虾(Pandalopsis japonica)和中华绒螯蟹(Eriocheir sinensis)几丁质酶3的同源性分别为54％和53％,与其他甲壳动物几丁质酶3聚为一支.RT-PCR显示,PtCht3基因具有较强的组织表达特异性,在肝胰腺中的相对表达量最高,在三疣梭子蟹蜕皮前期表达上调,低盐胁迫后在鳃和肝胰腺中表达量出现了波动,总体呈先上升后下降的表达趋势.推测PtCht3可能在三疣梭子蟹消化和蜕皮过程中发挥重要作用,参与三疣梭子蟹渗透压调节进程.本研究为三疣梭子蟹几丁质酶的功能研究提供了重要信息.     

所罗门群岛海域长鳍金枪鱼的垂直分布与环境因子的关系

根据2010年8-11月在中西太平洋所罗门群岛海域金枪鱼延绳钓作业,研究了长鳍金枪鱼的垂直分布与环境因子的关系。结果表明,在所罗门群岛海域,长鳍金枪鱼的最适水层为130．00～160．00m,最适水温范围为22．00～24．00℃．最适盐度范围为35．70～35．80;长鳍金枪鱼活动较频繁的水层范围为130．00-190．00m,水温范围为20．00-26．00℃,盐度段为35．60～35．90。     

八棱海棠耐盐碱性评价

为探明八棱海棠的耐盐碱性种质资源价值,以实生苗为试材,采用水培的方法评价了八棱海棠耐盐性和耐碱性.结果表明:1)0.4％ NaCI处理30 d时,八棱海棠的盐害指数为51.1,根据耐盐性评价标准判定为中等耐盐型树种;其实生个体间存在广泛的抗性分离现象,极强、强、中、弱和极弱耐盐型植株分别占群体总数的20.6％、23.9％、37.0％、12.0％和6.5％.2)pH9.5碱处理(Na2CO3)30 d时,八棱海棠的碱害指数为16.3,根据耐碱性评价标准判定为极强耐碱型树种;其实生个体间存在广泛的抗性分离现象,极强、强、中、弱和极弱耐碱型植株分别占群体总数的79.1％、15.3％、4.2％、1.4％和0％.八棱海棠中存在极强耐盐型和极强耐碱型植株,是优异的耐盐/碱型种质资源树种.