In vitro evaluation of some high yield potato (Solanum tuberosum L.) cultivars under imposition of salinity at the cellular and organ levels

Salinity and drought stress, which combines a lack of water and sodium toxicity, are more of the problems faced by plants and agricultural crops in newly reclaimed lands. Therefore, the direction of our research is to produce salinity-tolerant plants to increase the productivity of crops under conditions of salt stress. Potato callus was studied using different concentrations of NaCl (0.0, 50, 75, 100, 125, 150 and 200 mM). Shoot induction was obtained from callus treated with MS medium containing 4.0 and 5.0 mg l^?1 TDZ + 0.5 mg l^?1 GA3 with NaCl up to 125 mM and 150 mM for Rosetta and Victoria, respectively. When plantlets were cultured on MS medium containing 3.0 mg l^?1 kinetin and 1.0 mg l^-1paclobutrazol (PBZ) with 80 or 90 g l^?1 sucrose after two months gave a good microtuber per explant of Rosetta and Victoria cultivar which gave number of microtuber/plantlet (1.85) and (2.40) when plantlets treated with 125 mM and 150 mM NaCl of Rosetta and Victoria cultivar, respectively. In general, the results were shown in each treatment of NaCl and that amounts of proline at 125 and 150 mMNaCl were significantly more than 0.0, 50, 75 and 100 mM NaCl. This result is related to the role of proline in the osmotic adjustment of a higher concentration of salinity. The results showed that the amounts of sodium increased with increasing the salt concentration, but the amount of potassium decreased and also increased the Na+/K+ ratio with increasing the salt concentration. This research is important for in vitro potato plant regeneration, which requires optimization before genetic transformation can be achieved.     

能源植物杂交狼尾草对NaCl胁迫的响应及其耐盐阈值

以能源植物杂交狼尾草(Pennisetum americanum × P. purpureum)为实验材料, 用沙培盆栽的方法, 分别用0、0.3%、0.5%、0.9%和1.2%的NaCl处理4周后, 测定植株鲜重、干重、含水量、株高、分蘖数和不同部位的离子含量, 以确定其耐盐阈值和耐盐方式。结果表明, 随着NaCl浓度的增加, 杂交狼尾草的鲜重、干重、株高和分蘖数都显著降低, 地上部分鲜重和干重分别在NaCl浓度为0.568%和0.570%时下降了50%, 1.2% NaCl处理的杂交狼尾草几乎全部死掉。表明杂交狼尾草的耐盐阈值为0.57%; 但植株含水量和功能叶的Na⁺含量变化不明显, 老叶Na⁺含量在NaCl浓度为0.9%时明显升高, 是对照的2倍; 随NaCl浓度的升高, 根中的Na⁺含量显著升高, 在NaCl浓度为0.9%时, 根中的Na⁺含量达到对照的3倍以上。Na⁺含量在功能叶, 老叶和根中含量依次升高; 随NaCl浓度的升高, 地上部分和根中的K⁺含量都无明显变化; 随NaCl浓度的升高, 根中的Na⁺/K⁺明显增加, 而地上部分Na⁺/K⁺只有当NaCl浓度为0.9%时明显增加。以上结果表明杂交狼尾草具有一定的耐盐性, 其耐盐方式为拒盐, 耐盐阈值为0.57% (约100 mmol·L^-1)。     

盐胁迫对长春花幼苗生长和生物碱含量的影响

以NaCl浓度分别为0、50、100、150、200和250 mmol·L^-1的1/2 Hoagland营养液处理长春花幼苗,7 d后测定其鲜质量、干质量、丙二醛(MDA)和叶绿素含量、色氨酸脱羧酶（TDC）和过氧化物酶（POD）活性等生理指标及文多灵、长春质碱、长春新碱和长春碱等生物碱含量.结果表明：NaCl显著地降低长春花幼苗的鲜质量和干质量,提高MDA含量;叶绿素含量在低盐浓度(50 mmol·L^-1)下与对照相比差异不显著,在高于50 mmol·L^-1时随NaCl浓度的增加而逐渐降低;在NaCl处理下,POD活性与对照相比显著上升;TDC活性在50 mmol·L^-1 NaCl处理下活性最高,而后随盐浓度的增加逐渐降低;文多灵、长春质碱、长春新碱和长春碱含量都是在50 mmol·L^-1NaCl处理下最高,分别为4.61、3.56、1.19和2.95 mg·g^-1,并显著高于对照及其他处理.盐胁迫虽然在一定程度上抑制了长春花幼苗生长,但促进了其生物碱的代谢,提高了生物碱含量;50 mmol·L^-1NaCl处理对长春花吲哚生物碱代谢的促进作用最大.     

盐胁迫对不同生境盐地碱蓬光合及离子积累的影响

为了探讨盐地碱蓬(Suaeda salsa)适应不同生境的生理机制, 研究了盐处理(1、200和600 mmol·L^-1 NaCl)对盐碱地和潮间带两种生境盐地碱蓬地上部分及根系有机干重、叶片叶绿素含量及光合放氧速率、叶片和根中离子积累的影响。结果表明: 200 mmol·L^-1 NaCl对两种生境盐地碱蓬地上部分及根系的有机干重无显著影响, 说明两种生境盐地碱蓬均具有较强的抗盐性; NaCl处理显著降低了两种生境盐地碱蓬叶片的光合放氧速率; 各浓度NaCl处理下, 盐碱地生境盐地碱蓬叶片的光合放氧速率均高于潮间带生境的, 潮间带生境盐地碱蓬叶片中叶绿素a与叶绿素b的比值均高于盐碱地生境的; 各浓度NaCl处理下, 潮间带生境盐地碱蓬叶片中的Cl^-含量均低于盐碱地生境的; 与叶片中情况相反, 高盐处理下, 潮间带生境盐地碱蓬根中的Cl^-含量均高于盐碱地生境的。说明与盐碱地生境盐地碱蓬相比, 潮间带生境盐地碱蓬的根系可能对Cl^-具有较强的积累或限制其向地上部分运输的能力, 这些特征可能是盐地碱蓬适应不同生境的结果。     

Response of greenhouse tomato to salt stress and K+ supplement

Abstract

The effect of NaCl salinity and potassium supplement on growth, tissue ion concentration, photosynthesis, yield and fruit quality characteristics of tomato plants was studied. Tomato plants, hyb. Belladonna, were grown in 8.5 l pots, filled with 1:3 sand:perlite mixture and irrigated with a half-strength Hoagland solution through a closed hydroponic system. Six irrigation treatments were applied, including combinations of 3 salinity (0, 35 and 70 mM NaCl) and two potassium levels (K1: 200 ppm and K2: 400 ppm) in the nutrient solution. Salinity reduced photosynthesis resulting in reduced plant height and dry weight. Yield was reduced by 25% and 69% at 35 and 70 mM, respectively, as compared to control plants (0 mM NaCl). Both total soluble solids and titratable acidity of the fruit increased with increasing salinity and K levels. The application of high potassium level (K2) reduced the concentration of Na and increased that of K in the leaves and roots of the plants, as compared to K1 treatment. Toxicity symptoms were mostly observed in the leaves of 70K1 plants, while no visual symptoms of toxicity were observed in 70K2 treatment. Despite the positive effects of potassium supplement in reducing Na concentration and the absence of toxicity symptoms in the leaves, plant growth was not improved, while leaf photosynthesis was reduced. Furthermore, no positive effects in the percentage of marketable fruit, mean fruit weight and yield were observed in the plants receiving extra K.     

Optimization of Exopolysaccharide Overproduction by Lactobacillus confusus in Solid State Fermentation under High Salinity Stress

It is believed that high concentrations of sodium chloride (NaCl) suppress the biosynthesis of exopolysaccharide (EPS) in lactic acid bacteria (LAB). Nevertheless, overproduction of EPSs due to high salinity stress in solid state fermentation performed on an agar surface was demonstrated in this study using a response surface methodology via a central composite design (CCD). Under optimized conditions with NaCl 4.97% and sucrose 136.5 g/L at 40.79 h of incubation, the EPS yield was 259% (86.36 g/L of EPS), higher than the maximum yield produced with the modified MRS medium containing only 120 g/L of sucrose without NaCl (33.4 g/L of EPS). Biosynthesis of EPS by Lactobacillus confusus TISTR 1498 was independent of biomass production. Our results indicated that high salinity stress can enhance EPS production in solid state fermentation.     

盐胁迫对二穗短柄草幼苗生长及不同器官中盐离子稳态的影响

采用4种浓度的NaCl溶液(50、100、150、200 mmol/L)处理二穗短柄草和拟南芥(对照)幼苗,测定不同浓度盐胁迫下2种植物幼苗的生长指标和离子分布,以探讨二穗短柄草在盐胁迫下主要阳离子平衡机制.结果表明:(1)盐胁迫显著抑制二穗短柄草根叶的生物量积累.(2)根冠比数据显示,在盐胁迫条件下二穗短柄草能够更好地维系地下部分的生物量积累.(3)在4种浓度盐胁迫下,二穗短柄草叶中Na+含量低于根系,而且K+、Cl-含量和K+/Na+比值始终高于根系,说明在二穗短柄草中Na+从地下到地上的转运受到抑制,但对Cl-的转运缺乏有效的调控.(4)回归分析发现,盐胁迫下二穗短柄草和拟南芥根部Na+与K+含量变化呈正相关关系,而在叶部则不相关,说明二穗短柄草和拟南芥Na+与K+在根部具有相同的离子通道,而在叶部却具有各自独立的转运途径.     

Melanin is crucial for growth of the black yeast Hortaea werneckii in its natural hypersaline environment

Melanin has an important role in the ability of fungi to survive extreme conditions, like the high NaCl concentrations that are typical of hypersaline environments. The black fungus Hortaea werneckii that has been isolated from such environments has 1,8-dihydroxynaphthalene-melanin incorporated into the cell wall, which minimises the loss of glycerol at low NaCl concentrations. To further explore the role of melanin in the extremely halotolerant character of H. werneckii, we studied the effects of several melanin biosynthesis inhibitors on its growth, pigmentation and cell morphology. The most potent inhibitors were a 2,3-dihydrobenzofuran derivative and tricyclazole, which restricted the growth of H. werneckii on high-salinity media, as shown by growth curves and plate-drop assays. These inhibitors promoted release of the pigments from the H. werneckii cell surface and changed the medium colour. Inhibitor-treated H. werneckii cells exposed to high salinity showed both decreased and increased cell lengths. We speculate that this absence of melanin perturbs the integrity of the cell wall in H. werneckii, which affects its cell division and exposes it to the harmful effects of high NaCl concentrations. Surprisingly, melanin had no effect on H. werneckii survival under H₂O₂ oxidative stress.     

Effect of Salinity on Zinc uptake by Brassica juncea

Salinity is a major worldwide problem that affects agricultural soils and limits the reclamation of contaminated sites. Despite the large number of research papers published about salt tolerance in Brassica juncea L., there are very few accounts concerning the influence of salinity on the uptake of trace metals. In this study, B. juncea plants divided through soil sets comprising 0, 900 and 1800 mg Zn kg^?1, were treated with solutions containing 0, 60 and 120 mmol L^?1 of NaCl, with the purpose of observing the effect of salt on Zn uptake, and some physiological responses throughout the 90 days experiment. Increasing concentrations of NaCl and Zn produced a decline in the ecophysiological and biochemical properties of the plants, with observable synergistic effects on parameters like shoot dry weight, leaf area, or photochemical efficiency. Nevertheless, plants treated with 60 mmol L^?1 of NaCl accumulated striking harvestable amounts of Zn per plant that largely exceed those reported for Thlaspi caerulescens. It was concluded that salinity could play an important role on the uptake of Zn by B. juncea. The potential mechanisms behind these results are discussed, as well as the implications for phytoremediation of Zn on saline and non-saline soils.