生物菌肥和钾肥配施对苹果钾素吸收及果实品质的影响

为了研究生物菌肥和钾肥对苹果果实品质及生长发育的协同作用,以7 a生'瓦里短枝'(Vallee spur Del)为研究对象,设置T1(K2O 420 kg·hm-2)、T2(生物菌肥2520 kg·hm-2)、T3(生物菌肥2520 kg·hm-2+K2O 294 kg·hm-2)、T4(生物菌肥2520 kg·hm...     

盐碱地公园绿化树种的选择

为更好地指导大庆市及采油七厂公园盐碱地的绿化,在规划地土壤表层化学性质测定的基础上,参照不同树木耐盐能力上限,分别对全盐量在0.1%～0.3%、0.3%～0.5%、0.5%～0.7%、＞0.7%的131个样点上绿化树种的生长状况进行了调查及分析,并进而给出了树种选择及绿化工作的建议.     

大庆市碱草草原土壤呼吸的日变化研究

采用碱液吸收法对大庆市碱草草原土壤呼吸速率进行了测定.测定结果表明:土壤呼吸的一天中变化比较明显,呈现双峰型曲线.自然状态下碱草草原土壤呼吸速率的年平均值为401.40 mg·m-2·h-1.     

广东优质稻品种的引进与利用Ⅰ.长沙地区引种表现及利用前景

为了充分利用广东优质稻的优良性状,改良和提高湖南优质稻的性状水平,在分析广东优质稻品种的遗传背景、品种类型、农艺性状、抗病性、稻米品质和产量水平的基础上,结合湖南优质稻品种（组合）的主要性状特点,对20个广东优质稻品种引入湖南长沙夏播时的主要性状表现及其在湖南水稻育种上的利用前景进行了初步研究.结果表明,广东优质稻品种引入湖南一般可以作一季晚稻种植,少数可以作双季晚稻种植;20个品种的理论产量为6 430.5～9 271.5 kg/hm^2,品种间差异很大,大多数品种属于矮秆大穗型;12个品种无垩白粒,8个品种有垩白粒,但垩白粒率很低;所配30个杂交稻组合有14个的结实率为75.07%～82.43%,与对照汕优63的75.1%～84.9%基本一致,有10个组合单株产量的超亲优势在20%以上,6个组合单株产量的竞争优势在10%以上,其中优IA/华新占的超亲优势与竞争优势最高,分别为61.7%和32.32%.     

稻田镉(Cd)污染的土壤修复技术研究进展

自从20世纪50年代中期日本”骨痛病”发生以来,镉污染尤其食物的镉污染等引起了全世界的普遍关注。近几年来,镉米在中国部分地区也相继发现,促使中国对镉污染的研究予以高度重视。主要回顾了中国关于稻田镉污染控制及其防治研究的现状,简要介绍了镉污染治理途径及其原理、优缺点和可行性,并对今后的研究方向提出了一些看法。     

Effects of supplemental phytic acid on the apparent digestibility and utilization of dietary amino acids and minerals in juvenile grass carp (Ctenopharyngodon idellus)

A feeding trial was conducted for 8 weeks to evaluate the effects of supplemental phytic acid (PA) on the apparent digestibility and utilization of dietary amino acids (AAs) and minerals in juvenile grass carp. Five experimental diets consisted of graded levels of PA (0.2, 4.7, 9.5, 19.1 and 38.3 g kg^?1, named as P0, P5, P10, P20 and P40). Triplicate groups of fish (initial weight, 22.37 ± 0.16 g) were fed twice daily (08:00 and 16:00 h). The crude protein content in whole body significantly (p < .05) decreased in fish fed with 19.1 and 38.3 g PA kg^?1 diet. Supplemental PA (>4.7 g kg^?1) significantly reduced the apparent digestibility coefficient (ADC) of AAs (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Phe, Lys, Pro, His and Arg) and the ADC of minerals (P, Ca, Mg, Zn, Cu, Fe and Mn) in grass carp. The contents of minerals (P, Ca, Mg and Zn) in whole body and bone were also found to be significantly reduced in dietary PA > 4.7 g kg^?1, while the bone ash, serum Alkp and Zn contents were found to be significantly decreased when the PA supplementation level was above 9.5 g kg^?1, and the contents of serum Ca and Mg were found to be markedly altered in higher PA‐supplemented groups. The results indicated that supplemental PA decreased the apparent digestibility and utilization of AAs and minerals, and thus reduced the feed utilization of grass carp, suggesting that the level of total PA should be below 4.7 g kg^?1 in grass carp diet.     

Dry whey meal as a protein source in practical diets for Nile tilapia,Oreochromis niloticus fingerlings

ABSTRACT

This study was conducted as a trial of using dry whey meal (DWM) as a substitute for fish meal (FM) in practical diets for Nile tilapia, Oreochromis niloticus. Triplicate fish groups were fed on five isonitrogenous (30.2%) and isolipidic (6.9%) diets. The control diet (D1) used FM as the sole protein source. In the other four diets (D2–D5), FM protein was substituted by 25, 50, 75, or 100% DWM. Fish (3.5 ± 0.1 g) were stocked at a rate of 20 fish per 100-L aquarium and fed one of the tested diets up to satiation twice daily for 12 weeks. Fish growth, feed utilization, protein efficiency ratio, apparent protein utilization, and energy utilization for fish fed DWM diets up to 75% FM (D2–D4) tended to be higher but were not statistically different than the control diet. No significant effect of diet was found in whole-body moisture, crude protein, and total ash contents. Whole-body lipid content in fish fed the 100% DWM (D5) diet was significantly higher than that for fish fed the control diet. The optimal replacement level of FM by DWM was estimated by second-order polynomial regression to be 62.5%.     

聚维酮碘对海湾扇贝等贝类幼虫的毒性试验研究

测定了聚维酮碘(PVP—I)对虾夷扇贝、海湾扇贝、牡蛎的壳预期幼虫以及牡蛎的眼点期幼虫的24h半致死浓度分别为：32．5mg／L，31．7mg／L，44．4mg／L；安全浓度分别为：3．25mg／L，3．17mg／L，4．48mg／L，4．44mg／L。     

Protein and Energy Metabolism of European Seabass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>) Juveniles and Estimation of Maintenance Requirements

The present work aimed to study metabolic utilization of energy and protein by juvenile European seabass reared at 25 °C and to estimate maintenance requirements, based on indirect calorimetry and nitrogen excretion measurements. Duplicate groups of fish (IBW = 22 g) were fed a practical diet, for 28 days, at ration levels of 0, 0.25, 0.5, 1 and 1.5% of body weight. At the end of this period, oxygen consumption and ammonia nitrogen excretion were measured in fed and unfed fish. Weight gain linearly increased with ration level. Feed efficiency significantly increased with nitrogen intake up to 0.68 g N/kg/day. Nitrogen retention (% N intake) was positive at all feeding levels, being maximum at 0.5% BW and then decreased with increasing ration levels. There was negative energy balance at the lowest ration level and significantly increased at higher ration levels. Daily oxygen consumption (g/kg body mass) and ammonia excretion (mg N–NH₄/kg body mass) significantly increased with ration level. Heat production and heat increment of feeding (kJ/kg/day) remained low at low ration levels and significantly increased as ration level increased from 0.5 to 1.5% BW. Below maintenance, protein energy represented 34% of total energy expenditure and significantly increased to 49–56% above maintenance. Based on indirect calorimetry and ammonia excretion data, maintenance energy and protein requirements were estimated to be 56.8 kJ DE/kg/day and 1.15 g DP/kg/day, respectively. The efficiencies of energy and protein utilization were estimated to be 0.83 and 0.66, respectively.     

四种稻田农药对克氏原螯虾的急性毒性研究

采用半静态方式水生生物急性毒性实验法,研究了在实验室常温条件下敌百虫、稻瘟灵、毒死蜱、阿维菌素四种稻田杀虫剂对克氏原螯虾（ Procambarus clarkii）的急性毒性。结果显示,敌百虫、稻瘟灵、毒死蜱、阿维菌素对体重为（34.43±7.04）g克氏原螯虾的24 h半致死浓度（24 h LC50）分别为65.07、42.16、0.71、1.23 mg/L,48 h半致死浓度（48 h LC50）分别为35.75、33.49、0.59、0.84 mg/L;96 h半致死浓度（96h LC50）分别为12.54、18.83、0.45、0.37 mg/L。其安全浓度分别为3.24、6.34、0.122、0.117 mg/L。根据国家标准和本实验数据可以看出,敌百虫和稻瘟灵对克氏原螯虾中毒,毒死蜱和阿维菌素对其高毒。