肃南牦牛屠宰性能和肉品质研究

为研究肃南牦牛的屠宰性能及肉品质,揭示其遗传特性,选取12头(公母各半)4岁放牧肃南牦牛进行屠宰试验和肉品质分析,并与文献中已报道的甘南牦牛、天祝白牦牛、雪多牦牛、环湖牦牛等进行了对比分析.结果显示,肃南牦牛的活重和胴体重均高于环湖牦牛和天祝白牦牛,屠宰率高于查乌拉牦牛和环湖牦牛,净肉率高于甘南牦牛和环湖牦牛,熟肉率高...     

贡山县核桃增效配套技术

笔者在贡山县应用了核桃大树“开槽放水”杂劣品种嫁接改良技术、漾濞大泡核桃“2-3主枝自然开心形或2-3主枝开心圆头形”树形配置技术和“平衡施肥”技术,总结出了适合贡山县核桃增效的配套技术,供参考使用.     

乡土植物在青海省高等级公路绿化中的应用

乡土植物是在长期的系统演化过程中,经过严格自然选择的优胜者,它们与当地的气候、土壤相适应,具有适应性广、抗病虫害能力高、抗逆性强等特点。本文通过总结近年来乡土植物在青海公路绿化中的实践经验,就如何合理规划应用乡土植物进行了阐述。     

Characterization of two races of the stem and bulb nematode (Ditylenchus dipsaci) in Israel

Two distinct races ofDitylenchus dipsaci in Israel were identified: one, which infects and damages onion and garlic, reproduces on pea, but does not infect phalaris grass; and a second, which infects and damages phalaris—and, probably, also ‘Saia’ oats—but fails to infect onion and garlic. A new ‘garlic’ race of the nematode does not appear to have been introduced into Israel together with the ‘Lavinia’ garlic cultivar, as previously speculated, but rather the introduced Lavinia clone is highly susceptible to the existing ‘onion and garlic’ race ofD. dipsaci.     

成熟期短时渍水胁迫对烤烟碳氮代谢关键酶及主要碳、氮化合物含量的影响

以烤烟云烟97为材料,采用田间试验研究了成熟期短时渍水处理对烤烟碳氮代谢关键酶活性及主要碳、氮化合物含量的影响。结果表明,在烤烟成熟期渍水处理3 d,中部叶片硝酸还原酶活性低于对照,降幅为20.39%;转化酶和淀粉酶活性高于对照,增幅分别为33.14%,56.70%;烟叶淀粉、总氮和烟碱含量有降低趋势,分别下降了2.9,0.74,0.77个百分点,而总糖和还原糖含量有增加趋势,分别上升了1.33,0.46个百分点。说明渍水胁迫使叶片生理代谢紊乱,氮代谢减弱,碳水化合物积累减少。研究结果有助于从生理生化角度揭示成熟期渍水胁迫对烤烟生长和品质形成影响的机制。     

低氮胁迫下拟南芥低氮耐性突变体lnt1的氮代谢特征

A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen (N) metabolism of a low-N tolerant mutant (lnt1) of Arabidopsis thaliana under different N levels as compared with the wildtype (WT) Arabidopsis. On the agar medium, no apparent growth differences were observed between the lnt1 and WT plants under a normal N level of 9 mmol L^-1 NO₃^-. However, under a low N level of 0. 18 mmol L^-1 NO₃^-, the growth of the WT plants was greatly retarded, while the lnt1 plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lnt1 mutant had higher activities of glutamine synthetase (GS) and NADH-dependent glutamate synthase (NADH-GOGAT) in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium (NH₄⁺) but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.