马齿苋组培与耐盐筛选

为了扩大耐盐植物资源,促进沿海滩涂植物资源利用,以马齿苋(Portulaca oleracea L .)的嫩叶和茎段为试验材料,研究了不同浓度激素和 NaCl 对愈伤组织生长与分化的影响.结果表明:MS +0.10 mg?L‐1 NAA 时,马齿苋茎段生根率较高,生长健壮;MS +2.00 mg?L‐16‐BA 是不定芽诱导的最适培养基;MS +2.00 mg?L‐16‐BA +1.00 mg?L‐1 NAA 是分化的最适培养基;在最适分化培养基中添加100 mmol?L‐1 NaCl ,诱导产生的愈伤组织为5%,大部分愈伤组织生长受抑制,同时也说明马齿苋具有一定的耐盐性.     

Progress in Plant Salinity Resistance Research: Need for an Integrative Paradigm

SUMMARY

Population pressure, shortage of good arable land and good quality waters are forcing crop production into more marginal environments facing abiotic stresses (drought and salinity) and thereby limiting the adaptation and productivity of staple food crops. The situation is assuming serious proportion, as almost half of the existing irrigation system of the world is under the influence of secondary salinity, sodicity or waterlogging. Therefore, to maintain productivity of existing arable land, the sustainability of the agricultural and irrigation systems that has been generated at a huge cost, is more important than immediate increases in yield. Much work done in the last century in several countries has increased our understanding of the genetics and physiology of salt tolerance of plants. Crop responses to salt stress are made up of a number of complex and interrelated, morphological, physiological, and biochemical processes. However, we still do not have a complete understanding of the underlying mechanisms of salt tolerance. The multigenic, quantitative nature of salt tolerance imposes several limitations on the efforts to improve salt tolerance of plants. The biological approach to tackle problems of salinity has its critics as well as advocates. Identification and development of crops and their cultivars with improved salt tolerance has been the key to improve productivity. Efforts in this direction using traditional methods of plant breeding and modern tools of biotechnology have led to the development and release of many cultivars with improved salt tolerance at the global level. Many of these superior cultivars have yet to prove their worth in actual stress situations. Integrative approaches in this direction, including the frontier areas of plant molecular biology have been discussed. In view of the enormity of the situation and immense challenges involved, efforts in this direction have to be more focused and multidisciplinary in approach. This should receive much higher priority and resources from scientists, administrators, and policy makers.     

Ammonium determination in soil extracts by the salicylate method

Abstract

An ammonium determination, based on formation of a substituted indophenol with sodiumsalicylate as phenolic reagent, has been reexamined. An increase of 70% in absorbancy compared with existing salicylate methods in soil science, and an increase in reproducibility compared with pre‐existing equivalent methods in other disciplines were obtained. The method can be applied satisfactorily for ammonium in 2M KCl soil extracts and soil and plant digests. The use of salicylate in place of phenol is advised for safety reasons.     

盐胁迫对苜蓿营养品质及附着微生物群落的影响

本试验旨在研究盐胁迫对苜蓿营养品质及附着微生物群落的影响。试验处理包括无盐胁迫(盐含量<1‰,作为对照)、轻度盐胁迫(盐含量1‰～2‰)、中度盐胁迫(盐含量2‰～3‰)和重度盐胁迫(盐含量3‰～4‰)。每个盐胁迫试验处理设置3个小区,每个小区面积为30 m²(5 m×6 m)。结果表明：中度盐胁迫下苜蓿酸性洗涤纤维和中性洗涤纤维含量显著低于其他处理(P<0.05)。中度盐胁迫下苜蓿谷氨酸、脯氨酸、可溶性蛋白质、粗蛋白质和可溶性碳水化合物含量与其他处理相比显著增加(P<0.05)。所有处理的Shannon指数和Chao1指数均无显著差异(P>0.05)。主坐标分析(PCoA)显示盐胁迫未完全改变苜蓿表面附着微生物群落的结构。所有处理下苜蓿门水平附着核心菌群为变形菌门(84.48%～92.91%)、放线菌门(4.30%～6.47%)、拟杆菌门(0.39%～10.59%)和厚壁菌门(0.61%～3.02%),属水平附着核心菌群为泛菌属(47.17%～56.11%)、假单胞菌属(10.58%～19.88%)、鞘脂单胞菌属(5.69%～9.32%)、...     

海水胁迫下冰草幼苗期耐盐性指标筛选

冰草植物为禾本科小麦族多年生牧草,具有耐干旱、抗寒冷、耐盐碱等优点,是盐碱地改良的优良作物。为给冰草种质耐盐性评价提供依据,本试验对2个冰草主栽品种,蒙农1号蒙古冰草和蒙农杂种冰草,通过温室花盆培育在幼苗期进行了5个海水浓度的梯度胁迫,经30 d胁迫后,对各浓度处理材料的株高(SH)、根长(RL)、超氧化物歧化酶(SOD)、丙二醛(MDA)和K⁺等共12项农艺性状和生理指标进行了测定。探究盐胁迫对冰草幼苗的生长特征、K⁺/Na⁺、抗氧化酶活性和渗透调节物质等的影响;通过公式计算各项指标在不同浓度海水处理下的耐盐系数,进一步对其采用主成分分析、模糊隶属函数分析和逐步回归方程等方法进行耐盐性系统评价。结果表明：供试材料在不同浓度盐胁迫处理下除苗相对含水量无显著差异外,各指标间均存在显著差异(P<0.05);利用主成分分析法筛选得到了10项可对冰草种质材料幼苗期进行耐盐性鉴定的指标;总结出3个盐胁迫因子,分别为渗透调节因子、株型因子、根系因子;利用逐步回归方程方法得出了可用于冰草种质材料耐盐性预测的回归模型,D=0.83...     

铜-季铵盐复配木材防腐剂的防腐性能

在实验室内采用常规的真空－加压法浸注试件，土壤木块法进行防腐试验，检验了铜－季铵盐类防腐剂（FFJ－1、FFJ－2和FFJ－3）对白腐采绒革盖菌[Coriolus versicolor(L.ex Fr.)Quel.]和褐腐绵腐卧孔菌[Poria placenta(Fr.)Cooke.]的防腐性能，结果表明：在较低的保持量下，都有较好的防腐效果。与百菌清（可湿性粉剂）、五氯酚钠、三唑酮相比较，它们对白腐菌的防腐性能与百菌清相近，批五氯酚钠和三唑酮好。     

盐胁迫对盐蒿种子萌发及保护酶活性的影响

为更好地开发盐蒿资源,对不同浓度的NaCl和Na2SO4胁迫下盐蒿种子萌发过程中发芽率、酶活性(SOD、POD)、MDA含量的变化进行了研究。结果表明:3种盐处理均抑制种子萌发,NaCl、Na2SO4提高了SOD酶活性,降低了POD的酶活性。     

Water,salt and nutrient fluxes of tropical tidal salt flats

The water budget of a tropical tidal salt flat in dry tropical Australia has been studied with particular emphasis on estimating the groundwater fluxes. Salt was used as a passive tracer to determine some of these fluxes. Groundwater salt accumulation (or loss) was less than 1 kg/m³/month. Surface water leaving the flat at a higher salt concentration than flood water causes a net outwelling of salt of between 0.4 and 1 kg/m²/month. Evaporation from the salt flat was estimated to be 70 mm/month. Using these measurements and a simple model of the groundwater flows, it is concluded that the groundwater loss is less than 40 mm/month. The accuracy of the salt budget was insufficient to rule out the possibility that the net groundwater motion was upwards. Measurements of Si and PO_{_4} fluxes indicated that the net outwelling due to surface water flows were respectively 3 mmole/m²/month and 0.014 mmole/m²/month. A net groundwater loss of 10 mm would produce a similar magnitude outwelling due to groundwater discharge. The mangrove-fringed tropical tidal salt flats are the source of large quantities of nutrients that are released to the near-shore zone.     

黄河三角洲不同造林模式下土壤盐分和养分的变化特征

研究黄河三角洲重盐碱地5年生白刺林和新淤地上18年生不同类型林分土壤盐分和养分的变化规律。结果表明：白刺造林后显著地促进了土壤脱盐，明显地提高了土壤肥力；新淤地上植树造林能有效抑制土壤返盐，培肥地力；不同类型林分防止土壤次生盐渍化的效果没有差异，杨树、刺槐行间混交林提高土壤肥力的效果最好。