低磷胁迫对小麦镉吸收的影响

为探究低磷胁迫下小麦根系生理和形态的变化及其对镉的吸收能力的影响,以Ca₃（PO₄）₂作为磷源,通过砂培试验研究了在低磷胁迫下小麦根系形态和分泌物变化特征,以及这些变化对难溶态镉（CdCO₃）的活化与吸收的影响。结果表明,在低磷处理中,小麦地下部生物量显著低于对照,降幅为27.3%（P<0.05）,根长度、根表面积和根体积均显著变小（P<0.05）。此外,低磷胁迫下小麦地上部和地下部磷含量均显著降低,降幅分别为35.4%和23.1%（P<0.05）,但是显著促进了难溶态磷的溶解（P<0.05）。同时还发现低磷胁迫显著提高了小麦植株Cd含量和Cd的总活化量,增幅分别为190.8%和82.8%（P<0.05）。低磷胁迫下培养基pH降低了0.3,同时根中草酸根和苹果酸根含量显著升高,增幅分别为1 588.1%和37.7%（P<0.05）,由此可见,低磷胁迫下小麦通过分泌质子和羧酸根促进了磷的活化,并促进了Cd的活化,进而导致小麦Cd吸收的增加。这些结果阐明了低磷胁迫影响小麦Cd吸收的机制。     

Lactobacilli counts in crop,ileum and caecum of growing broiler chickens fed on practical diets containing whole or dehulled sweet lupin (Lupinus angustifolius) seed meal

1. Four experiments with growing broiler chickens were carried out to study the effects of the inclusion in their diets of lupin (Lupinus angustifolius ) seed meal on E. coli and lactobacilli counts in crop, ileum and caeca at 3 or 4 weeks of age. 2. Diets were formulated to contain the same amounts of metabolisable energy (12.55 MJ/kg) and protein (210 g/kg). Raw whole (heat-untreated) or dehulled sweet (low in alkaloids) lupin seed meal (400 and 320 g/kg respectively) were used to prepare the lupin-based diets, whose protein content was completed with either defatted soyabean meal or casein. 3. Final body weight and food intake of chickens fed on whole lupin seed meal diets were lower than controls, but gain: food ratios were not different. However, birds given the diet with dehulled lupin seed meal had similar body weight, food intake and gain: food values as those of controls. 4. While E. coli counts were not affected, lactobacilli numbers were consistently increased compared to controls in all intestinal sections of chickens fed on the whole or dehulled lupin-based diets, irrespective of the age of the birds or the presence of soyabean meal or casein in the diet. The lactobacilli species isolated were: Lactobacillus fermentum, L. acidophilus, L. salivarius and L. brevis 5. The results suggest that the use of whole or dehulled sweet lupin seed meal in diets for growing broilers might enhance the growth of lactic acid-fermenting bacteria in the gut.     

青海省海南州高寒草地荒漠化治理技术与对策

总结了海南州高寒干旱草地荒漠化特征和成因,分析出气候变化、毁草开荒、超载过牧、鼠类危害、利用不当、执法不严等是草地荒漠化的主要原因,通过对荒漠化草地实行人工补播优良牧草、灭除毒草、消灭鼠害、禁牧封育、暖棚养畜、营造饲料护牧林等措施,提出了防止草地荒漠化的对策及治理技术.     

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。     

野生龙葵果中营养成分的研究

本研究对野生龙葵果营养成分进行了比较全面地分析测试,对矿物质及维生素含量进行分析的基础上,对野生龙葵果的其它营养成分进行了分析,并与一些常用果蔬进行了对比研究。结果表明,野生龙葵果含有丰富的营养成分。     

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。     

Effects of feeding practical diets containing different protein levels, with or without fish meal, on growth, survival, body composition and processing traits of male and female Australian red claw crayfish (Cherax quadricarinatus) grown in ponds

Four practical diets containing 2% of crude protein (CP) (180 and 280 g kg^?1), with or without menhaden fish meal (FM), were fed to Australian red claw Cherax quadricarinatus during a 97‐day feeding trial. Growth, survival, body composition and processing traits of pond‐cultured red claw were determined. Juvenile red claw (mean individual weight of 5.75 ± 3.3 g) were randomly stocked into twelve 0.04‐ha ponds at a rate of 1000 per pond (25 000 ha^?1), and each diet was fed to three ponds. At harvest, the final mean weight of red claw fed Diet 4 (0 g kg^?1 FM and 280 g kg^?1 CP) and Diet 3 (113 g kg^?1 FM and 280 g kg^?1 CP) was significantly (P < 0.05) higher (62.4 and 58.5 g, respectively) than red claw fed Diet 1 (73 g kg^?1 FM and 180 g kg^?1 CP; 51.7 g) and Diet 2 (0 g kg^?1 FM and 180 g kg^?1 CP; 53.0 g). Red claw fed diets containing 280 g kg^?1 CP, with or without FM, had significantly higher percent weight gain (894 and 959%, respectively) compared to red claw fed 180 g kg^?1 CP, with or without FM (778 and 799%, respectively). Feed conversion ratio, percent survival, and total yield among treatments, which averaged 3.55, 65.2%, and 724 kg ha^?1 overall, were not significantly different. Results from this study indicate that pond‐cultured red claw stocked at 25 000 ha^?1 can be fed a practical diet containing 280 g kg^?1 CP with 0 g kg^?1 FM if a combination of plant‐protein ingredients (soybean meal, distillers’ dried grains with solubles, and milo) is added; however, if the percentage of dietary protein level is 180 g kg^?1, growth is reduced even if FM is added at 73 g kg^?1 of the diet. Use of diets containing plant‐protein sources may help reduce diet costs to producers and thereby, increase profits.     

Comparison of media used for the primary isolation of Mycobacteriurm bovis by veterinary and medical diagnostic laboratories

Veterinary and medical laboratories engaged in the cultural diagnosis of bovine or human tuberculosis were requested to supply samples of the media that they routinely use for the primary isolation of M. bovis. Fourteen laboratories supplied 7 basic media types; these were Lowenstein-Jensen, Stonebrink's, modified Middlebrook 7H11 agar, tuberculosis bovine blood agar, egg yolk agar, Gerloff's egg and Herrold's egg yolk. Two strains of M. bovis were used to test the media, strain AN5, a glycerol-tolerant laboratory strain and M86/90 a glycerol-sensitive wildtype strain. AN5 grew well on all media with the exception of Herrold's and strain M86/90 did not grow on media containing glycerol and grew poorly on Herrold's medium. It is recommended that Lowenstein-Jensen with pyruvate (but without glycerol), Stonebrink's, modified Middlebrook 7H11 and tuberculosis bovine blood agar should be considered the media of choice for the primary isolation of M. bovis. Egg yolk agar also proved adequate for this purpose in the trial. This medium may be suitable for routine use but to date experience with its use is limited.