真鲷窒息点与耗氧率的初步测定

真鲷(Pagrosomus major T and S)是广东及其他各省市沿海海水网箱养殖的主要鱼类之一。随着真鲷人工繁殖和苗种培育的成功,真鲷养殖业将会有一个更大的发展。夫于鱼类的窒息点与耗氧率的研究早有不少,但是对真鲷除个别学者提及其窒息点外,真正对其窒息点与耗氧率的系统研究尚未见到。为了绘其鲷的人工繁殖、苗种培育、运输和成鱼养殖提供呼吸生理方面的理论依据,笔者于1990年春对真鲷的窒息点和耗氧率进行了初步测定,就不同规格大小的苗种及备种外界条件与窒息点和耗氧率之间的关系进行了初步探讨。     

人工养殖西伯利亚鲟精子超低温冷冻保存研究

研究了人工养殖西伯利亚鲟精子的生物学特征及超低温冷冻保存方法。西伯利亚鲟的产精量为113.67±39.86 ml,精子密度为(6.49±3.10)×108/ml,精子活力为(85.4±9.5)%,精子寿命为353±23 s。精子密度与精子快速运动时间、精子寿命之间均存在线性相关,用方程分别表示为:y=1.0384x+1.5089(R2=0.7325);y=2.9069x+74.289(R2=0.6967)。结果表明精子密度可作为一项精子质量评价的标准。通过比较西伯利亚鲟精子在不同稀释液、不同抗冻剂和抗冻剂浓度、降温速率、解冻温度下的保存效果,结果表明:配方2作为稀释液,18%甲醇作为抗冻剂,二步法超低温(-196℃)冷冻保存精子,40℃水浴解冻取得最好的冻后活力,解冻后活力为(51.8±5.8)%。西伯利亚鲟授精的最佳精卵比为106∶1。在此精卵比下用冻精授精分别得到了(72.3±3)%的受精率和(52.9±4.1)%的孵化率,其中受精率与鲜精没有显著性差异,孵化率与鲜精有显著差异(P<0.05)。     

Effect of cryoprotectants, extenders and freezing rates on the fertilization rate of frozen striped catfish, Pangasius hypophthalmus (Sauvage), sperm

The effects of four cryoprotectants (methanol, MeOH; dimethyl sulphoxide, DMSO; dimethyl acetamide, DMA; and ethylene glycol, EG), three extenders (calcium‐free Hanks' balanced salt solution, C‐F HBSS, Hanks' balanced salt solution, HBSS and sodium chloride, NaCl) and two different freezing procedures (one‐ and two‐step) on the cryopreservation of striped catfish (Pangasius hypophthalmus (Sauvage)) sperm were investigated. Sperm were frozen using a controlled‐rate freezer in 250 μL straws and stored for 2 weeks in a liquid nitrogen (LN₂) container. They were then airthawed at room temperature, and fertilization, motility and viability were assessed. The highest fertilization rate of 41% (81% of control) was achieved with the combination of 12% DMSO and 0.9% NaCl using a one‐step freezing procedure (10°C min^?1). Also, DMA resulted in a higher fertilization rate (30% or 51% of the control) than MeOH (18% or 38% of the control) or EG (8% or 12% of the control). In addition, the three extenders used did not affect fertilization rates after cryopreservation with each cryoprotectant. There were no significant differences among the three cryoprotectant concentrations and between the one‐ and two‐step freezing procedures. However, fertilization rates of cryopreserved sperm were significantly lower than the controls (P<0.05). The results of this study indicate that high fertilization rates of striped catfish eggs can be achieved using cryopreserved sperm when frozen at 10°C min^?1 in DMSO or DMA with either 0.9% NaCl or C‐F HBSS.     

湖南省生猪定点屠宰管理情况调研

为了解生猪定点屠宰管理的现状和存在问题,湖南省农业部门对长沙市、郴州市、衡阳市等地的屠宰管理情况进行了实地调查研究,并在此基础上提出了相应的对策和建议,为规范生猪定点屠宰管理提供了参考。     

半滑舌鳎耗氧率和窒息点的初步研究

对半滑舌鳎的耗氧率和窒息点进行了初步研究。结果表明,在各个盐度梯度下,半滑舌鳎的耗氧量和耗氧率与体重(W)之间的关系可用幂函数Q=aWb表示,其中,耗氧量与体重呈正相关,耗氧率与体重呈负相关,方差分析表明,盐度和体重对半滑舌鳎的耗氧量和耗氧率均有极显著的影响(P<0 01);不同规格半滑舌鳎耗氧率的最高值均出现在同一盐度组,最低值则因体重不同而出现在不同的盐度组。半滑舌鳎的耗氧率无较明显的昼夜变化,夜里的耗氧率略大于白天,昼夜两阶段耗氧率的差异不显著。窒息点随着温度和体重的增加而有所增加,在较低的温度下,半滑舌鳎有很强的耐低氧能力。     

Isolation of pituitary glycoprotein gonadotropins from the grass carp (Ctenopharyngodon idell)

Gonadotropins (GTH) were isolated from pituitary glands of grass carp and their properties investigated. Acetone-dried pituitaries were extracted with ammonium acetate-ethanol and were then passed through cation exchanger, anion exchanger, and gel filtration column. Two glycoprotein gonadotropins (DE I and DE II) were isolated of MW 56,000 and 53,000 daltons, respectively, as determined by gel filtration technique. Isoelectric points of the two GTHs also differed from each other. Sialic acid contents were 3.64% and 1.47% for DE I and DE II, respectively. Both GTH's stimulated, in a similar manner, testicular androgen and ovarian estradiol synthesisin vitro.     

茶园晚霜冻害及其防治

茶园晚霜冻害造成茶树芽叶焦灼甚至枝梢枯死亡,严重影响茶叶产量和品质。本文对晚霜冻害发生的原因及影响因素,就防御晚霜冻害发生的措施以及灾后补救等方面研究进行了综述,以期为有效降低晚霜冻害影响提供参考。     

旱冻双重胁迫下的冬小麦幼苗长势遥感监测研究

为了探讨"旱冻交加"的气候条件下遥感监测小麦苗情的可行性,以河南省冬小麦为例,利用多时相MODIS为遥感数据源,引入了广泛用于小麦苗情监测的距平植被指数(AVI),同时基于植被健康状态指数(VHI)和晚霜冻害综合指数(I),构建了旱冻双重胁迫条件下的小麦苗情综合指数(CI),以反映冬小麦拔节期的生长状况,并分别利用实测样点苗情分类和距平植被指数对结果进行验证。结果表明,CI的总体分类精度为85.00%,Kappa系数为0.74;冬小麦总茎数与CI呈线性正相关关系,拟合方程为y=8.732CI+1.256,决定系数为0.605 3;与实测样本对比,CI预测精度为73.30%,苗情分类分级更符合小麦生长实际情况。因此认为旱冻双重胁迫下可以利用CI对冬小麦苗情进行监测。     

华南芒果种植区寒冻害危险性区划与评估

利用华南（广东、广西、福建）芒果种植区115个气象站1961−2016年观测资料,结合芒果寒冻害指标,采用加权综合评价法,确定种植区各气象站点的寒冻害危险性指数,建立寒冻害危险性指数与地理因子之间的多元线性回归模型,并基于GIS技术对华南芒果种植区寒冻害危险性进行区划。结果表明：华南芒果种植区寒冻害危险性与地理因子之间关系密切,总体呈现由沿海到内陆,寒冻害危险性逐渐变大的趋势,此外,随着纬度和海拔的增高,从南到北芒果寒冻害危险性程度也逐渐增大。轻度危险区主要分布在华南芒果种植区南部沿海地带及部分内陆地市的低海拔地区,占种植区面积比例为56.85%,该区域适合大规模种植芒果;中度寒冻害危险性区域主要分布在华南芒果种植区内陆中低海拔地区以及北部高纬度沿海地区,占种植区面积比例为37.03%;重度以上的寒冻害危险性区域主要分布在华南芒果种植区内陆高海拔地区,占种植区面积比例为6.12%。通过历史灾情和各县区年产量资料验证,区划结果与实际较为吻合,研究结果可为华南地区芒果的优化布局和防灾减灾提供参考。