虫白蜡还原法制备高级烷醇混合物研究

通过虫白蜡还原法制备高级烷醇混合物探索研究,得到虫白蜡制备高级烷醇混合物的工艺优化条件:10 g虫白蜡还原制备高级烷醇,氢化铝锂用量0.7 g,四氢呋喃溶剂用量70 mL,在65℃、常压和超声波作用条件下,进行还原反应5 h后,用水煮沸洗涤2~3次,过滤,滤饼烘干,虫白蜡转化率可达到95%~98%。用有机溶剂重结晶高级烷醇混合物后,用气相色谱测定组成为二十六烷醇56%、二十八烷醇32%、二十四烷醇5.2%、三十烷醇4.0%、二十五烷醇1.5%、二十七烷醇0.9%。     

Effects of Toxic Levels of Aluminium on Seedling Parameters of Rice under Hydroponic Culture

The presence of Al in the rhizosphere of rice in acid soil restricts root growth and significantly reduces crop productivity.In this study,the effects of Al(30,60 and 90μg/mL)on seedling root growth,number of primary roots per seedling,seedling shoot length,number of leaves per seedling,seedling fresh weight,and seedling dry weight were studied.Rice genotypes were classified into three different classes,namely,tolerant,moderately tolerant,and susceptible,based on root tolerance index.The method of hydroponic culture was modified,and elaborated in the text.Toxic levels of Al in nutrient solution significantly decreased seedling root growth,number of primary roots,seedling shoot length,number of leaves per seedling,seedling fresh weight,and seedling dry weight.Few genotypes showed longer root length at 30μg/mL Al in nutrient solutions compared with the control.High levels of Al in nutrient solutions were highly toxic for rice seedlings.Based on root tolerance index,Radhunipagal,Gobindobhog,Badshabhog,Kalobhog,UBKVR-11,UBKVR-16,UBKVR-18,Khasha and IVT4007-B were classified as tolerant genotypes,and these genotypes may be used as donors for breeding of Altoxicity tolerance.     

茶树根际土壤抗酸铝真菌ALF-1(Neurosporasp.)抗酸铝机理

利用膜分离技术和蛋白质电泳技术研究了ALF 1 真菌( Neurospora sp.) 的抗酸铝作用机理。结果表明, 铝对ALF 1 真菌的生长有促进作用。在含铝培养基中接种ALF 1 真菌后, 培养基pH 上升, 活性铝含量下降。ALF 1 真菌降低培养基酸度和活性铝含量的效果随培养基的营养成分含量增加而提高。ALF 1 真菌主要通过对培养基铝离子的吸附、吸收及其分泌物对铝离子的沉淀作用而起到降低酸度和活性铝作用的。蛋白质电泳结果表明, ALF 1 真菌的抗酸铝能力并非铝诱导而获得的, 而是遗传固有的。     

Effects of L-NAME, a non-specific nitric oxide synthase inhibitor, on AlCl3-induced toxicity in the rat forebrain cortex

The present experiments were done to determine the effectiveness of a non-specific nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on oxidative stress parameters induced by aluminium chloride (AlCl₃) intrahippocampal injections in Wistar rats. Animals were sacrificed 3 h and 30 d after treatments, heads were immediately frozen in liquid nitrogen and forebrain cortices were removed. Crude mitochondrial fraction preparations of forebrain cortices were used for the biochemical analyses: nitrite levels, superoxide production, malondialdehyde concentrations, superoxide dismutase (SOD) activities and reduced glutathione contents. AlCl₃ injection resulted in increased nitrite concentrations, superoxide anion production, malondialdehyde concentrations and reduced glutathione contents in the forebrain cortex, suggesting that AlCl₃ exposure promoted oxidative stress in this brain structure. The biochemical changes observed in neuronal tissues showed that aluminium acted as a pro-oxidant. However, the non-specific nitric oxide synthase (NOS) inhibitor, L-NAME, exerted anti-oxidant actions in AlCl₃-treated animals. These results revealed that NO-mediated neurotoxicity due to intrahippocampal AlCl₃ injection spread temporally and spatially to the forebrain cortex, and suggested a potentially neuroprotective effect for L-NAME.     

磷化铝熏蒸光肩星天牛虫害木的试验研究

用磷化铝对聚氯乙烯薄膜覆盖下的大官杨、箭杆杨光肩星天牛虫害木进行熏蒸试验表明,当磷化铝用量10～12 g/m3、密封时间为72 h时,杨树天牛幼虫死亡率均达100%,杀虫效果良好.该法使用方便,成本低廉便于推广应用.     

铝处理对苜蓿种子萌发及其幼苗生理生化特性的影响

在种子萌发试验中,低于０．１ｍｍｏｌ／Ｌ的Ａｌ＾３＋处理对苜蓿种子的萌发无明显的影响,高于０．１ｍｍｏｌ／Ｌ的Ａｌ＾３＋处理则明显降低种子的发芽数量,速度和质量,降低萌发种子的蛋白酶活性和自由氨基酸的含量,加速种子的电解质外渗。在幼苗生长的试验中,低于０．０５ｍｍｏｌ／Ｌ和Ａｌ＾３＋处理对苜蓿幼苗的生长略有促进作用,０．１ｍｍｏｌ／Ｌ的Ａｌ＾３＋处理对其无明显的影响,高于０．１ｍｍｏｌ／Ｌ的Ａｌ＾     

A mechanistic model for the inhibiting effects of aluminium on the uptake of cations

Reported laboratory observations mention inhibiting effects of Al on uptake of cations. However, the diverse conditions of these experiments do not allow conclusions to be drawn about the extent of this inhibiting effect. An uptake model for Ca and Mg was therefore developed to study the interactions of Al and these cations. The model is based on surface complexation of the root surface with both specific adsorption reactions and exchange reactions included. Application of this model to experiments using a nutrient flux growth technique showed that the observed effects are well simulated. The behaviour of the model agreed with reported inhibiting effects of Al. The model showed that Al effects might be reversed by increased nutrient solution concentrations of cations. However, there exists a strong competitive interaction between Ca and Mg. Therefore, high Ca concentrations have a negative effect on the uptake of Mg. Plants with a high growth rate and a high shoot to root ratio appear to be more sensitive to Al effects than more slowly growing plants.