烟蚜茧蜂Aphidius gifuensis滞育诱导研究

研究了不同温度、光周期以及温光组合条件对烟蚜茧蜂滞育诱导的效果。结果表明,僵蚜形成前,各种温度、光周期及温光组合条件均著的作用。僵蚜形成后,低温可大量诱导产生滞育,０℃处理３０ｄ,６０％以上个体进入滞育,而光周期的诱导作用仍不明显。作者认为你温是引起烟蚜茧蜂滞育的主要因素,处理的敏感时期为老熟幼虫－预肾期。滞育虫态为肾。     

甘蔗光周期诱导开花和杂交利用研究

本文报道了１９９８年度云南省甘蔗研究所光周期诱导甘蔗开花及杂交利用结果。本研究以４月１日和６月１日两种起始处理时间,１２ｈ２５ｍｉｎ和１２ｈ１５ｍｉｎ两种固定日长处理,于１０月１日起日递减光３０ｓ至抽穗时止的光周期诱导技术分别对７个难花亲本和７个常用亲本进行了开花诱导。结果表明：在不同的光周期处理下,粤糖５７／４２３、Ｃｏ４１９、闽糖７０／６１１、罗汉蔗等４个难花亲本被诱导开花;７个常用亲本全部孕穗或开花,并提早花期３－４个月。利用诱导开花亲本分别与割手密（Ｓ．ｓｐｏｎｔａｎｅｕｍ）、斑茅（Ｓ．ａｒｕｎｄｉｎａｃｅｕｍ）、滇蔗茅（Ｅ．ｒｏｃｋｉ）、芒（Ｍ．ｓｉｎｅｎｓｉｓ）、河八王（Ｎ．ｐｏｒｐｈｙｒｏｃｏｍａ）等野生种成功地进行杂交或远缘杂交,获得大量实出苗,为野生资源的利用及优良品种的选育奠定了基础。     

Diel Rhythms of Serum Metabolites and Thyroid Hormones in Red Porgy Held in Different Photoperiod Regimes

Diel rhythms in serum glucose, lactate, cholesterol, triglycerides and thyroid hormones were studied in red porgy, Pagrus pagrus, held under different photoperiod regimes (constant darkness – DD, 8L:16D,12L:12D), at a constant temperature (17.1–18.7 °C) and fed with commercial pellets, by means of a self-feeder. A clear diurnal rhythm in feeding activity, regardless of the photoperiod regime was demonstrated. All serum components showed significant diel rhythms, although they were not necessarily consistent or circadian in periodicity. As well as this, differences in the average values among the varying treatments were observed. Fish held under the 12L:12D protocol displayed significantly higher average T₄, T₃ and lactate levels during the day rather than at night. Maximum glucose values occurred 8–12 h after dawn and maximum lactate concentrations at 06:00 or 14:00 h. Diel variations in cholesterol were evident only in the DD group with peak values inversely correlated with the rhythm of food intake. Triglycerides displayed a similar pattern of changes. Significant diel fluctuations in T₄ serum levels were observed only in fish exposed to the 12L:12D protocol, with peak values at dawn. A clear diurnal peak (10:00 h) in T₃ concentrations was observed in fish subjected to the 12L:12D regime, while fish exposed to the 8L:16D protocol showed two peaks: one in the photophase (10:00 h) and another in the scotophase (02:00 h). The light–dark alternation and the general activity rhythm of fish seem to be the main synchronizers of the diel rhythms observed in this study.     

水温和光照对牙鲆亲鱼性腺成熟和产卵的影响

报道了不同水温和光照时间对牙鲆亲鱼性腺成熟和产卵的影响。通过提高水温和延长光照时间,可促使亲鱼提前1～5个月成熟和产卵,并得出促熟培育与光照时间和水温的相关方程式     

饥饿和光照对鳙仔鱼耳石沉积和日轮形成的影响

用同１尾雌鱼催产孵出的鳙鱼仔鱼进行了饥饿、光照对耳石沉积和日轮形成影响的实验研究。结果表明,仔鱼全长生长饥饿组慢于对照组,差异极显,ＤＤ组、ＬＬ组与对照组相接近,无显差异。耳石直径各实验组与对照组无显差异。饥饿组仔鱼在体长生长停止的情况下耳石仍能继续沉积。仔鱼孵出后第２ｄ形成第１轮,之后每天１轮,对照组１６日龄仔鱼耳石上有１５个日轮。饥饿组约９０％的个体烽比对照组少２０％,约１０％的个体耳石     

光敏核不育水稻研究利用中存在的若干问题

概述了近年来我国在光敏核不育水稻的理论与应用方面存在的一些问题,对这些问题作了分析与探讨,认为光敏雄性不育现象是一种复杂的光温、生理、生态现象,其生表达虽然主要受光温的双重影响,但学与多种因素有关,其具体和机理仍不清楚。要达到更好地遗传工具来人人类服务,还需做大量工作。     

Filial Cannibalism in the Swordtail Xiphophorus Helleri (Poeciliidae)

To understand behaviour during filial cannibalism in swordtails (Xiphophorus helleri), the parturition behaviour of eight individually kept females was recorded on videotape. Three levels of female activity (low, medium and high) were quantified by measuring the duration of each. Four additional behavioural events (non-cannibalistic feeding, as well as the birth, attack and cannibalism of juveniles) were quantified by determining the frequency of each. Females gave birth most frequently at a low level of activity and at this level of activity they most often gave birth at the top of the tank. Of all the attacks by females on the young, 84.4% occurred in the light. Most attacks were recorded at the bottom of the tank and 84.0% of all cannibalism occurred at the bottom. Cannibalism was most successful at the bottom of the tank with a cannibalism:attack ratio of 1:2.2 and least successful in the middle where no cannibalism was recorded. In the light, females spent more time at the top of the tank, whereas in the dark they spent more time at the bottom. It was suggested that the rate of cannibalism might be reduced if parts of the tank were kept constantly dark and if females were restricted from reaching those areas in the tank where the frequency of cannibalism was highest, namely the top and the bottom of the tank. Experimental designs and working hypotheses for future studies are discussed.     

光周期与氮肥互作对华农1号青饲玉米碳氮代谢相关酶的影响

于2005年3-7月,采用盆栽试验,设置3个不同光照长度处理和氮素水平,研究了不同光照时数及氮素水平对远缘玉米杂交种华农1号青饲玉米碳氮代谢相关酶活性的影响.结果表明,在苗期,16 h光照处理下植株叶片磷酸烯醇式丙酮酸羧化酶、蔗糖磷酸合成酶、蔗糖合成酶、谷氨酰胺合成酶和硝酸还原酶等酶的活性显著低于13和10 h光照处理;至抽雄期和收获期,13和10 h处理下植株叶片各种酶的活性下降速率较快,而16 h处理下酶活性下降缓慢且显著高于13和10 h处理.在抽雄期或收获期,16 h处理下叶片各种酶的活性均随施氮量的增加而增加,但在13和10 h处理下均有几种酶的活性在高氮素水平下出现下降的趋势.总的看来,在16 h光照处理下,植株苗期碳氮代谢相对较弱,到中后期代谢能力明显提高,且耐高氮能力也较强,收获期植株叶片酶的活性显著高于13和10 h处理.     

The effect of timing of extended photoperiod on growth and maturity of brook trout (Salvelinus fontinalis)

The influence of timing of extended photoperiods on growth and maturity of brook trout was investigated in a 112‐day experiment. The fish with mean initial weight of ~192 g were reared under four light regimes: one control group with natural ambient photoperiod and three groups exposed to an 18L:6D regime initiated at days 1, 23 or 46 of the growth trial. Light‐emitting diodes, with intensity of 250–1000 lux, depending on the distance from the light source, were used for extending light periods. There was a positive effect of prolonged day length on fish growth (p < 0.05), and a delay in gonad development and sexual maturity. Significantly higher numbers of sexually mature fish were found among controls groups, regardless of sex. Survival rate was not affected by light regime. This study demonstrated that the short‐term expansion of the photo period delayed maturation and increased the growth rate of brook trout.