Particle clearance and selection in three species of juvenile scallops

Juvenile scallops (<2 mm shell height) of three species (Placopecten magellanicus, Patinopecten yessoensis, Argopecten irradians) were fed mixed, unialgal cultures. Scallops were fed a total of six algal clones simultaneously and clearance rates were monitored using flow cytometric techniques. In another experiment, scallops were presented with natural assemblages of particulate matter as a food source. Data are presented on differences in clearance rates for the individual algal species as well as size-related differences of algal clones, and uptake of chlorophyll vs. non-chlorophyll cells, both within and between scallop species. Significant differences in clearance rates of individual algal species have been found within and between scallop species. Particle selection does not appear to be based upon size alone and is apparently based on other characteristics of the algae as well. The results demonstrate pre-ingestive sorting.     

Yields of cultured Pacific oysters Crassostrea gigas Thunberg improved after one generation of selection

Parental families (G₀) in three lines of Pacific oysters were selected based on live weight and meat yields at harvest. The average live weight yield of progeny (G₁) from crossing G₀-selected lines in seven trials was 9.5% greater than that of nonselected control families and live weight yields were significantly greater (ANOVA, P<0.001) in four out of seven trials. The response to selection was greater if G₁ families were tested at the same site as their parents' selection site rather than at a different site, although this effect was only significant for G₁ families of cohort 5 (P<0.01) but not cohort 7 (P>0.05). A significant genotype×environment interaction affected yields in both cohort 5 and cohort 7 (ANOVA; P<0.001). In addition, correlation between the yields of the same families planted at both intertidal and subtidal sites was positive but weak (cohort 5, r=0.30; cohort 7, r=0.35), indicating that selection for high yield in one environment would likely result in a low correlated response in a different environment. Nonetheless, it was possible to identify six families in cohort 5 and four families in cohort 7 that were among the top 10 families at both sites. Further evaluation of families across a wider range of environments is needed to determine if it is possible to substantially improve yields by selecting “generalist” families that perform well along the whole Pacific coast, or whether it will be necessary to select lines that are suited to particular sites.     

戈壁日光温室适栽口感型番茄品种筛选

口感型番茄具有皮薄、肉厚、多汁、酸甜适中等优点,越来越受到市场的青睐。为筛选出适宜河西地区戈壁日光温室有机生态型无土栽培的口感型番茄优良新品种,在酒泉市肃州区东洞戈壁农业生态产业园的戈壁日光温室对引进的9个口感型番茄新品种采用有机生态型无土栽培方式进行了品种筛选试验。结果表明,在酒泉市肃州区戈壁日光温室中,以戴安娜、原味1号为综合表现最优品种,其经济效益分别为1 075 200、 1 068 000元/hm2,可作为当地越冬茬日光温室采摘和高品质种植方向发展的主要品种。     

陇中旱作区马铃薯品种筛选试验初报

为筛选出适宜陇中旱作区种植的优质马铃薯品种,解决当地马铃薯生产中存在的品种老化、抗病性弱、产量低、品质差等问题。以当地主栽马铃薯品种陇薯6号为对照,对引进的7个马铃薯品种进行了品种筛选试验。结果表明,宁薯19号、 陇薯11号折合产量较高,分别为39 245、37 350 kg/hm2,分别较对照品种陇薯6号增产15.87%、10.27%。综合分析认为,宁薯19号、陇薯11号较对照品种陇薯6号增产幅度大,综合农艺性状好,可在陇中旱作区及类似生态区种植。     

红松天然林生长变异及早期选择的研究

[目的]探究红松早期选择的适宜年龄.[方法]对小兴安岭5个种源25株红松天然林个体进行了调查.[结果]红松天然林个体的生长变异随年龄增大而减小,40年是个体生长从激烈分化转为相对平稳的转折年龄.根据变异系数、相关系数和选择效率3个指标的分析,初步确定红松天然林早期选择的最佳年龄40年.可用40年的树高和胸径平方预估150年的材积.[结论]为红松选择优树、确定遗传改良试验鉴定年龄等育种手段提供了理论依据.     

产表面活性剂菌的筛选和验证实验研究

[目的]探究废弃钻井液中产表面活性剂菌株的性能.[方法]以废弃的钻井液为原材料,利用生物表面活性剂的性质进行产表面活性剂菌株的培养和筛选,并且将筛选出来的产表面活性剂菌进行排油活性和乳化性能的测定.[结果]筛选出的产表面活性剂菌排油圈的直径约为4 cm,乳化层初始较厚,1d后变薄.[结论]筛选出的产表面活性剂菌排油活性较好,但乳化性能不稳定.     

红松结实性状优良无性系与个体选择

以吉林省露水河林业局宏伟种子园收集的红松全分布区的优树无性系为材料,对其结实性状进行观测与综合分析,结果表明:在628个无性系中,选择出红松结实性状特别优良的无性系11个,优良无性系51个,共计62个。为今后建设红松种子园和果林基地提供了实践依据与基因储备。     

小麦慢条锈品种鉴定及筛选

对37份国内小麦品种（系）进行了成株期慢条锈鉴定,结果表明,兰天20号等6份材料具有高度慢条锈特性,陇原932等6份材料具有中度慢条锈特性,阜麦16等5份材料具有低度慢条锈特性,石麦11等5份材料具有中度快条锈特性,洮157等15份材料具有高度快条锈特性,同时对慢条锈品种田间判别方法及其研究利用进行了探讨。     

论网络道德与网络伦理

对网络道德与网络伦理不加分辨不利于伦理学、道德哲学的发展,也不利于网络具体问题的解决。本文从道德与伦理、个体网络行为与网络伦理关系、网络道德自由与网络伦理秩序三个层面,分别对网络道德与网络伦理的关系进行辨析,认为二者在理论和实践上均有各自侧重对象和范围,但就其形成与实现的现实性而又相互关联。     

亚热带常绿阔叶林11个树种的细根形态及碳氮含量研究

【目的】研究江西大岗山常绿阔叶次生林中11个树种的细根形态、组织化学元素含量与根序之间的关系。【方法】以大岗山次生林内6个受外生菌根侵染的树种(刨花润楠、小叶青冈、拟赤杨、丝栗栲、檵木和梓木)和5个受内生菌根侵染的树种(山乌桕、深山含笑、杉木、木荷和油桐)为研究对象,采用根序分级法对根系进行分级后,测量并比较各树种前5级根之间根长、比根长及C、N含量的差异。【结果】在细根形态方面,11个树种的根长均表现出随序级升高而增大的趋势,而比根长的表现则相反;在细根C、N含量方面,除3个树种(山乌桕、檵木和梓木)5级根C含量小于4级根、1个树种(油桐)2级根C含量小于1级根外,其余7个树种根组织的C含量均表现为随序级升高而增加;11个树种中除山乌桕外,其余10个树种根组织的N含量均表现为随序级升高而降低;在C/N上,有9个树种的C/N随序级升高而增加,其余2个树种(山乌桕和梓木)4级根的C/N略高于5级根。在不同树种间,同一序级的细根在细根形态和C、N含量上差异明显。6个受外生菌根侵染树种的根长和C、N含量均较5个内生菌根侵染树种大,而比根长以外生菌根侵染树种相对较小。【结论】11个树种前5级根根长、比根长、C含量、N含量和C/N随着序级增加而表现出相似的变化规律,生长在根系先端的1级根根长、C含量和C/N最小,比根长和N含量最大,随着序级的增加,根长、C含量和C/N增加,而比根长和N含量降低。受外生菌根侵染的树种,其根长、C含量和N含量均大于受内生菌根侵染的树种。11个树种之间细根形态和C、N含量存在明显差异,表明不同树种对地下环境的适应策略及对土壤养分的利用效率存在差异。