济南市近年酸雨特征及其影响因素

根据2008~2012年济南市酸雨观测资料、探空资料和大气监测资料,分析了济南市酸雨的年、季变化特征,同时研究了酸性降水与气象条件和大气污染物的关系。统计资料证明:近5年济南市的酸雨无论从频率还是从强度上都呈现减弱趋势。降水pH值秋季最低,夏季最高;酸雨频率秋季最高,冬季最低。分析得出,影响济南市酸雨的主要大气污染物是PM10和SO2;在偏东风影响下,酸雨污染严重;酸雨的发生也会受逆温影响,降水前1 d及当天均出现逆温时,酸雨出现频率最高;随着降水量的增加,pH值逐渐降低,中雨时酸雨频率最高;另外,雾和轻雾也容易导致酸雨的发生。     

不同绿肥对植烟土壤养分及微生物含量的影响

为了对湘西旱地烟区改良土壤和提高烟叶质量提供依据,研究了5种不同绿肥品种对植烟土壤pH值、有机质和土壤养分含量及土壤微生物的影响。结果表明:翻压绿肥能有效地提高土壤pH值,明显增加土壤细菌数量和硝化细菌数量,有效地改善土壤环境,提高土壤肥力,各绿肥品种中以箭筈豌豆表现较好。     

福寿螺和田螺的纤维素酶反应体系对不同pH和温度的响应

【目的】探讨福寿螺Pomacea canaliculata Lamarck和本地中国圆田螺Cipangopaludina chinensis Gray纤维素酶活性反应体系对不同pH和温度响应的差异.【方法】采用酶学分析法（羧甲基纤维素法）测定不同反应温度和pH对福寿螺和田螺肝脏与胃纤维素酶活性的影响.【结果和结论】福寿螺肝脏和胃纤维素酶的活性在不同pH和温度条件下均显著高于田螺,其中,不同pH(3.6～7.2)条件下福寿螺肝脏和胃纤维素酶活性分别是田螺的1.51～3.14和1.30～1.90倍;不同温度(30～60 ℃)条件下福寿螺肝脏和胃纤维素酶活性分别是田螺的1.16～1.56和1.32～1.77倍.在pH3.6～7.2、温度30～ 60 ℃的范围内,福寿螺和田螺肝脏、胃纤维素酶活性都呈先上升后降低的变化趋势,不同温度条件下福寿螺纤维素酶活性的变化幅度大于田螺,但2种螺纤维素酶活性随pH的变化差异不显著.福寿螺肝脏和胃纤维素酶适宜的pH范围分别为5.4～6.6和4.8～ 6.6,适宜的温度范围均为40～55 ℃;田螺肝脏和胃纤维素酶适宜的pH范围分别为5.4～6.0和4.8～6.6,适宜的温度范围均为40～50 ℃.福寿螺对外界环境的适应性更强.     

粤桂甘蔗产区不同类型土壤pH值及其酸性改良数学方程

采集粤桂甘蔗主要产区不同类型土壤,测其p H值,并测定调节土壤pH值至5.5、6.0、6.5需要的碳酸钙和白云石粉用量,并且以要调至土壤pH值减去原值数值为自变量(x)、需要碳酸钙量为因变量(y)进行数学模拟,得出不同类型土壤酸性改良数学方程,为不同土壤类型酸性土壤改良提供参考。结果表明,粤桂甘蔗产区土壤pH值为3.72～5.50,调节至土壤pH值5.5、6.0、6.5需要施用碳酸钙或白云石粉量因土壤类型而存在较大差异,以玄武岩类型需要量最少。不同类型土壤酸性土改良与碳酸钙用量数学方程及相关系数:第四纪红土为y=3 388.5x-1 599.75,相关系数R=1;浅海沉积物发育而成土壤为y=3 391.95x-720.105,相关系数R=0.999 6;玄武岩发育而成土壤为y=2 742.6x-1 041.96,相关系数R=0.990 5。     

绿色巴夫藻培养条件的研究

研究了温度、光照强度、光照时间、酸碱度和相对密度对绿色巴夫藻生长繁殖的影响,结果表明:绿色巴夫藻在水环境pH6 0～9 5、相对密度1 005～1 020的范围内都能生长,pH6 5、相对密度1 015条件下生长率最高;温度在5～35℃范围内都能生长,20～30℃为适宜温度;光照强度在1000～10000Lx范围内都能生长,4000Lx为最适光照强度。光照强度<1000Lx时,绿色巴夫藻的生长速率与光照时间成正比。     

解剖采集的珠母贝精子的激活条件

解剖成熟珠母贝（Pinctada margaritifera)并采集其精子，在不同pH、盐度和温度条件下进行激活实验。结果显示，水温25℃、盐度34、pH8.5以下时，珠母贝精子的激活率与活力均很低，pH9.0-10时激活率与活力均较高，pH9.5时的激活率最高；在水温20℃，盐度34时珠母贝精子只能在pH9.5-10激活，且激活率与活力均比25℃时低。在水温25℃，pH9.5时，精子在盐度10-45能激活，盐度25-35时激活率和活力很高；在水温20℃,pH9.5时，精子只能在盐度20-40时激活。当盐度相同，20℃时的激活率与活力比25℃时低，在pH9.5或10的氨海水中，珠母贝精子在水温5-45℃时能激活，在25-30℃时激活率较高。当温度相同，pH9.5时的激活率比pH10.0时高。解剖得到的珠母贝精子的适宜激活pH9.5、适宜盐度为25-35、适宜温度为25-30℃。     

大鹏澳网箱养殖区沉积物硫酸盐还原菌（SRB）及其与环境因子关系的初步研究

实验采用MPN法测定了大鹏澳网箱养殖区沉积物中硫酸盐还原菌(SRB)的含量,布设的5个站位SRB检出率达100%,SRB平面分布特征是鱼类网箱区>对照区>浮筏贝类区;垂直分布特征为1cm层>5cm层>10cm层,SRB数量是由上向下逐渐减少。探讨了SRB含量与相应沉积物样品中的硫化物含量、氧化还原电位、pH等环境因子的关系。结果表明,沉积物中SRB数量与硫化物含量呈显著性正相关(R=0.96,P<0.05),与氧化还原电位(OPR)呈极显著性负相关(R=-0.97,P<0.01),与pH之间不具有显著性关系。     

Characteristics of burnt meat in cultured yellowtail <Emphasis Type="Italic">Seriola quinqueradiata</Emphasis>

ABSTRACT:   In order to understand the characteristics of burnt meat in cultured yellowtail Seriola quinqueradiata , fish were kept at two different temperatures (13 and 30°C) and slaughtered by either spinal cord destruction (SCD) or suffocation in air (SA). Early postmortem changes during storage at 32°C were analyzed by rheological, biochemical, and histological methods. The burnt meat (with lightness parameter, L* ≥ 55) was observed at 1-h storage in the SA 30°C group, at 2 h in SCD 30°C, and at 4 h in SA 13°C; meat was normal for the SCD 13°C group until 6 h of storage. Breaking strength scores were higher for the normal meat (200 g/cm²) than burnt meat (70 g/cm²) at 4 h of storage. Expressible water content was higher for the burnt meat than for the normal meat. Adenosine triphosphate concentrations for the SCD groups were higher than for the SA counterparts. Moreover, pH decrease was much faster in the 30°C groups, showing pH 5.6 at 2 h of storage. A negative correlation between the pH and lactic acid contents in muscle ( P  < 0.001) was found. Histological analysis evidenced a larger pericellular area (40%) in the burnt samples than in the normal samples (16%). It was confirmed that a higher fish-keeping water temperature and a stressful slaughter method (faster glycolytic process) were determinative factors that influence the occurrence of burnt muscle in yellowtail, and that the effect of the former is larger than the latter.     

Carbon dioxide reversibly inhibits sperm motility and fertilizing ability in steelhead (Oncorhynchus mykiss)

The effects of different carbon dioxide (CO₂) levels on the short-term storage of semen samples from hatchery-produced steelhead (Oncorhynchus mykiss) were evaluated. Sperm motility and fertilizing ability were significantly reduced following 4 h incubation under a relatively modest (0.9 kPa = 1%) amount of CO₂. The dose-dependent reductions, however, were not the result of cell death as sperm viability was unaltered even at the highest (5.2 kPa = 5.6%) CO₂ exposures. Reductions in sperm motility and fertilizing ability were reversible. Although previous work has indicated a direct relationship between salmonid sperm motility and sperm ATP content, the inhibitory effects of CO₂ on sperm motility were not the result of reduced sperm ATP levels. Decreasing the pH of the seminal fluid (to below 7.5) significantly reduced sperm motility. However, this effect was only observed after prolonged (4 h) exposure; short-term (1 min) exposure to this lowered pH did not alter sperm motility. Moreover, acetazolamide, a carbonic anhydrase inhibitor, attenuated the inhibitory effects of CO₂ on sperm motility. These results suggest that CO₂ inhibits steelhead sperm motility and therefore fertility in a dose-dependent manner, by reversibly lowering intracellular pH.