Volume regulation in glutathione-treated brook trout (Salvelinus fontinalis) erythrocytes

Brook trout erythrocytes that were washed with and suspended in Ringer's solution with reduced glutathione (1.0 mM) maintained steady state cell volume for up to 24h, while those without the thiol-protective agent steadily shrank. Changes in cell volume (measured as packed cell volume, PCV) were evoked by acidic media (Ringer's at pH 6.8), hypoosmotic solutions (or both) and intracellular K⁺ and Cl⁻ concentrations were monitored over 4h. Acid-swollen cells failed to volume regulate or release K⁺ but had significantly elevated intracellular Cl⁻ Osmotically-swollen cells at pH 7.8 but not at pH 6.8 underwent regulatory volume decrease (RVD) and returned to initial levels in 2h, accompanied by release of K⁺ and Cl⁻ In contrast, osmotically-shrunken cells did not show regulatory volume increase. The regulatory volume decrease and concomitant K⁺ release were dependent on Cl⁻ implying a direct or indirect coupling of K⁺ to Cl⁻ transport in volume regulation. RVD was partially blocked by 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS, 0.1 mM), an anion exchange blocker, but was unaffected by amiloride (1.0 mM) which blocks Na⁺/H⁺ exchange. Amiloride and DIDS prevented the swelling response to low pH but had no effect on control cells, suggesting involvement of Na⁺/H⁺ and Cl⁻/HCO₃ ⁻ exchanges in acid-induced cell swelling. Quinine (1.0 mM) a known blocker of K⁺ channels, exacerbated the osmotically-induced swelling but had little effect on the subsequent RVD and release of KCl. The results suggest that low extracellular pH inhibits neutral C⁻-dependent K⁺ release and the resultant regulatory volume decrease in osmotically-swollen cells.     

盐胁迫下胡杨和毛白杨叶细胞中的离子区隔化

该文以抗盐的胡杨和盐敏感的毛白杨组培再生苗为实验材料,利用X--射线微区分析技术研究盐胁迫下(为期20d的盐处理)叶片各种类型细胞内主要元素Na+、Cl-、K+的分布情况,测定的细胞类型包括:①叶脉细胞(叶脉维管束导管、叶脉维管束内部和外部的薄壁细胞);②叶肉细胞(栅栏组织、海绵组织);③表皮细胞(上、下表皮细胞).结果表明,胡杨和毛白杨叶细胞对盐离子的区隔化有明显差异:与毛白杨相比,盐处理后的胡杨叶细胞不但具有较高的拒Na+能力,即将Na+贮存在质外体中,而且液泡区隔Na+的能力也强于毛白杨.在Cl-的区隔化方面,对照处理胡杨各种类型的细胞(包括叶脉、叶肉和表皮细胞)Cl-浓度都高于毛白杨,但在盐胁迫下,胡杨叶片的细胞壁、液泡甚至叶绿体中Cl-的含量都低于毛白杨,这是胡杨根细胞限制Cl-离子根冠运输的结果.盐处理使胡杨叶片各种类型细胞中的K+浓度降低;与胡杨不同,毛白杨叶片细胞中质外体的K+浓度下降,而液泡中的K+水平却相应提高,这是毛白杨细胞内K+重新分配的结果:由于盐处理后毛白杨液泡内积累了过多的Cl-,K+从细胞壁进入液泡,用以平衡液泡内Cl-积累所带来的负电荷.     

大叶榉人工栽培技术研究

榉树是国家二级保护树种，人工大面积栽培在国内尚未见报道。实践证明，榉树人工造林后生长良好。１年生苗高平均可在１ｍ以上，最高达１。７５ｍ，１０年生树，年平均高生长０．７８ｍ，胸径０．７２ｃｍ，优于同等条件下的马尾松，次于杉树，是优良的速生硬阔叶树种。人工林５０年可达工艺成熟，每亩年平均利润约７０００元，宜种子繁殖。     

油茶叶稀提取液中钾离子稳定性的分析

用盐酸萃取法和湿灰化法处理油茶叶试样,将其配制成3种pH值、4种不同浓度水平的稀溶液测定钾离子的含量。并对其稳定性进行研究,结果表明,这些溶液增加5%浓度的最短时间为6小时,浓度的增大增量为1.099ppm;浓度较高并已酸化的溶液,其稳定性可保持30小时以上。     

多胺交联纤维素树脂的合成及吸附性能(Ⅺ)——天然高分子吸附剂研究

报道了多乙烯多胺交联的纤维素树脂的合成及其对若干重金属离子的静态吸附性能和吸附机理。研究结果表明，该树脂能有效地吸附Ｃｕ２＋、Ｎｉ２＋、Ｃｏ２＋、Ｚｎ２＋、Ｐｂ２＋，其吸附量可分别达１．２８，１．２４，０．５８，０．６６和０．９９ｍｍｏｌ／ｇ。在ＨＯＡｃ－ＮａＯＡｃ缓冲溶液中可选择吸附Ｃｕ２＋、Ｎｉ２＋等离子而不吸附Ｐｂ２＋。     

Turbiscan Lab分散稳定性分析仪研究异丙甲草胺水乳剂物理稳定性

为获得不同因素对异丙甲草胺水乳剂物理稳定性的影响规律,同时验证Turbiscan Lab分散稳定性分析仪预测和评价水乳剂物理稳定性的可行性,利用Turbiscan Lab分散稳定性分析仪,结合加速试验[(54±2)℃,14d]结果,研究了乳化剂用量、体系pH和电解质离子等对磷酸酯盐稳定的异丙甲草胺水乳剂物理稳定性的影响。结果表明:乳化剂三苯乙烯基苯酚聚氧乙烯醚磷酸酯三乙醇胺盐(SCP)用量为6.0%(质量分数)时,水乳剂稳定性最好;过酸或过碱均会破坏水乳剂的稳定性,pH=9时水乳剂可获得较好的稳定性;Mg2+压缩油水界面双电层,导致水乳剂稳定性下降,且Mg2+添加浓度越大,水乳剂越不稳定。Turbiscan Lab分散稳定性分析仪以多重光散射为技术核心,在不破坏样品的前提下,能够准确测定乳状液中浮油、沉淀和液滴粒径大小的变化情况,与加速试验结果吻合度高,不仅能够缩短试验周期,而且可以分析不稳定现象发生的机理。     

Responses of Some Newly Developed Salt-tolerant Genotypes of Spring Wheat to Salt Stress: 1. Yield Components and Ion Distribution

The degree of salt tolerance of two newly developed genotypes of spring wheat, S24 and S36 was assessed with respect to their parents, LU26S (from Pakistan) and Kharchia (from India). These four lines along with a salt-tolerant genotype SARC-1 and two salt-sensitive cvs Potohar and Yecora Rojo were subjected to salinized sand culture containing 0, 125 or 250 mol m^?3 NaCl in full strength Hoagland's nutrient solution. S24 produced significantly greater grain yield and had greater 1000 seed weight and number of tillers per plant than those of the other cultivars /lines. S36 was not significantly different from its parents in seed yield and yield components. SARC-1 was the second highest in grain yield of all cultivars/lines, but it did not differ significantly from LU26S and Kharchia in 1000 seed weight and number of tillers per plant. The greater degree of salt tolerance of S24 could be related to its lower accumulation of Na⁺ in the leaves and maintenance of higher leaf K/Na ratios and K versus Na selectivity as compared to its parents. S36, which was as good as its parents in growth, also had lower Na⁺ and higher K/Na ratios and K versus Na selectivity in the leaves at the highest salt level than those in its parents. SARC-1 did not differ from LU26S and Kharchia in ionic content or K/Na ratios and K versus Na selectivities of both leaves and roots. Both the salt-sensitive cultivars, Potohar and Yecora Rojo, had significantly greater leaf Na⁺ and Cl^? concentrations and lower leaf K/Na ratios and K versus Na selectivities than all the salt-tolerant lines examined in this study. From this study it is evident that improvement in salt tolerance of spring wheat is possible through selection and breeding, and pattern of ion accumulation is not consistent among the salt-tolerant genotypes in relation to their degree of salt tolerance.     

Influence of chloride and sulphate ions on soil enzymes

Ammonium chloride (AC) and ammonium sulphate (AS) are commonly used nitrogen fertilizers. But the effect of chloride and sulphate ions from these fertilizers on soil enzyme activity has received scant attention. Hence, we conducted a pot culture study to assess the influence of chloride (as AC) and sulphate (as AS) on the activities of urease, amidase, phosphatase and dehydrogenase in soil using rice as the test crop. Chloride and sulphate levels were fixed at 132, 264 and 396 kg ha⁻¹ respectively. Controls were also performed. The enzymes were assayed at three stages of the crop growth viz., active tillering, panicle initiation and harvest.
The enzyme activities decreased with increasing chloride and sulphate levels; however, the degree of inhibition varied among the enzymes assayed and the nature and amounts of salts added. The inhibition may be due to the specific effects of chloride and sulphate ions on microbial growth and subsequent enzyme synthesis, osmotic desiccation leading to microbial cell lysis, and a salting-out effect modifying the ionic conformation of the active site of the enzyme protein.     

辐射敏化剂对离子注入小麦生物学效应的影响

采用中国科学院兰州近代物理研究所 2 0 0kV离子注入机产生的不同剂量Fe1+ ,对春小麦新品系 81 52 9种子进行注入并用辐射敏化剂后处理 ,研究其注入效应。结果表明 :①离子注入随注入剂量的增加染色体畸变率呈上升趋势 ;②不同辐射敏化剂后处理对萌发力、染色体畸变率影响程度不同 ;③不同辐射敏化剂对同一剂量Fe1+ 离子注入小麦的染色体畸变率影响的总趋势 :EDTA >秋水仙素 >咖啡因。     

Ion Transport Dynamics in Acid Variable Charge Subsoils

This is a mini-review of the research work conducted by the authors with the objective of studying ion transport in variable charge subsoils collected from different areas around the world. An attempt is made in these studies to relate the unique behavior manifested during ionic transport in these subsoils with their mineralogical, physical and chemical properties, which are markedly different from those in soils from temperate regions. The variable charge subsoils have a relatively high salt sorption capacity and anion exchange capacity (AEC) that retards anions downward movement. The AEC correlates closely with the anion retardation coefficients. Ca²⁺ applied with gypsum in topsoil may be transported to the subsoil and may improve the subsoil chemical properties. These results may help in developing appropriate management strategies under a range of mineralogical, physical, and chemical conditions.