玉米-大豆间作对草地贪夜蛾生长发育及繁殖的影响

为绿色防控草地贪夜蛾Spodoptera frugiperda,通过生命表研究玉米和大豆对草地贪夜蛾生长发育和繁殖能力的影响,同时室内测定草地贪夜蛾幼虫和成虫对玉米及大豆的产卵选择性和取食趋向性,并通过室内和田间小区试验研究玉米-大豆间作对草地贪夜蛾种群发生的影响。结果显示,取食大豆后草地贪夜蛾可以完成生活史,但与取食玉米相比,取食大豆会导致草地贪夜蛾发育迟缓,存活率降低,成虫期缩短,繁殖力下降和产卵天数减少;取食玉米的草地贪夜蛾种群的内禀增长率、周限增长率和净增殖率均显著高于取食大豆的草地贪夜蛾种群,取食玉米的草地贪夜蛾种群的平均世代周期低于取食大豆的种群,但两者间差异不显著。与大豆相比,草地贪夜蛾幼虫和成虫均对玉米有明显的趋性。当玉米与大豆按照2∶2比例间作时,植株上的草地贪夜蛾着卵率为65.31%,显著低于玉米单作的着卵率。当大豆包围玉米和玉米与大豆按照2∶2比例间作时,玉米的被害率分别为86.67%和85.56%,均显著低于玉米单作的被害率。表明玉米与大豆按适度比例间作可以显著降低草地贪夜蛾的发生和为害。     

Reproductive behaviour of tetraploid alfalfa plants obtained by unilateral and bilateral sexual polyploidization

The objective of the present study was to evaluate the fertility of tetraploid plants obtained from diploid mutants that produced 2n gametes via bilateral (BSP) and unilateral sexual polyploidization (USP) schemes. Controlled matings between selected plants from BSP and USP were carried out according to a complete diallel. The level of male and female fertility of each plant was estimated within full-sib, half-sib and non-inbred crosses. Crosses with unrelated self-fertile and male-sterile testers were also performed. Pollen size and stainability were determined by acetocarmine staining. The number of ovules per ovary was counted and the callose deposition within ovules examined to evaluate embryo sac fecundity. Cross-fertility was generally much higher for USP than BSP plants (on average, 0.3 vs. 0.03 seeds per flower pollinated). Both male and female fertility were inversely related to the inbreeding level of cross combinations. The in vitro pollen germinability was positively correlated to male fertility of BSP plants. The level of in vivo embryo sac sterility was not correlated to female fertility in either BSP or USP plants. Female fertility was restored in both BSP and USP groups when plants were crossed with unrelated tetraploid testers. Male fertility also increased in USP plants but remained rather low in the BSP plants. Scaling up the ploidy level by means of 2n gamete union resulted in tetraploid plants with low fertility. In particular, the BSP process yielded virtually self-sterile and highly cross-sterile plants. The well documented positive effect of sexual tetraploidization on forage yield was accompanied by worsening of fertility traits. This revised version was published online in July 2006 with corrections to the Cover Date.     

嘉陵江下游短体副鳅个体生殖力的研究

[目的]为短体副鳅资源保护提供理论依据。[方法]以189尾雌性短体副鳅为试材,对其中161尾进行年龄鉴定;考察该鱼的绝对生殖力（F）（以第4期卵粒数量表示）和F与其体长（L）、净体重（W）、年龄的关系,体长相对生殖力（F/L）与L和年龄的关系,体重相对生殖力（F/W）与W的关系,并对该鱼的卵径分布进行研究。[结果]短体副鳅的F为102～574粒,F/L为1.887～9.111粒;F与L和W呈直线相关,线性方程分别为F=7.5462L-181.96和F=34.096W＋140.74;161尾雌鱼中,1龄鱼42尾,2龄鱼59尾,3龄鱼52尾,4龄鱼7尾,5龄鱼1尾;F与年龄无明显相关性;F/L随年龄增大而减小;F/L与L的方程为F/L=0.0484L＋1.5920,F/W与W的关系为F/W=-6.8869W＋98.647;卵径分布只出现1个高峰,且峰值卵径所占比例较大。[结论]短体副鳅为一次性产卵鱼类。     

营养强化和控光控温对大菱鲆亲鱼性腺发育及卵子质量的影响

【目的】总结出一套有效的大菱鲆亲鱼培育技术,为大菱鲆育苗育种工作提供参考。【方法】通过人工控光控温,并投喂冰鲜杂鱼和强化饵料,研究大菱鲆亲鱼培育期间的控光控温和营养强化效果及其对亲鱼性腺发育、卵子质量的影响。【结果】经控光控温和营养强化后,大菱鲆亲鱼性腺开始发育提前67d,性腺发育时间缩短9d,产卵持续时间缩短18d,亲鱼平均产卵量867mL,受精卵活率高达80.1%,受精率67.3%,孵化率61.9%。进一步比较分析,发现控光控温能够使性腺发育时间提前60d,且能在一定程度上缩短性腺发育时间和产卵期;经营养强化后亲鱼产卵量、上浮卵量、上浮率及受精卵活率、孵化率均有显著提高。亲鱼产卵量与体重呈正相关,受精卵活率与孵化率也呈正相关。【结论】大菱鲆亲鱼经营养强化和控光控温后,卵子质量显著提高,性腺发育时间显著提前,实现了反季节产卵。     

温度对玉米截形叶螨实验种群繁殖的影响

将截形叶螨Tetranychus truncatus Ehara分别置于15℃、20℃、25℃、30℃和35℃的恒温箱内,观察温度对其实验种群繁殖的影响.结果表明:不同温度对子代雌雄性比的影响差异不一致,15℃与其它各温度、20℃与35℃的子代雌雄性比均有极显著的差异;20℃与30℃下的子代雌雄性比有显著的差异;20℃与25℃、25℃与35℃、25℃与30℃、30℃与35℃下的子代雌雄性比无显著差异.截形叶螨寿命、产卵期均随着温度的升高而缩短;截形叶螨在25℃时产卵量最高,因此25℃是该螨产卵繁殖的最适温度;30℃～35℃是种群繁殖增长的最适温度.     

羊多胎性状候选基因的研究进展

从骨形态发生蛋白15(BMP15)基因、生长分化因子9(GDF9)基因、视黄醇结合蛋白4(RBP4)基因、视黄酸受体γ(RARG)基因、催乳素(PRL)基因、催乳素受体(PRLR)基因、褪黑激素受体基因、促性腺激素释放激素(GnRH)及其受体(GnRHR)基因方面综述了羊多胎性状候选基因的研究进展.     

Life‐history variation in a species complex of nonmigratory galaxiids

Life‐history theory predicts that the optimal strategy in the trade‐off between egg size and number varies in relation to resource availability and environmental disturbance. We assessed interspecific differences in egg size, fecundity and other life‐history traits in a species complex of stream‐resident galaxiid fish, which are distributed across a range of contrasting habitat types on the South Island, New Zealand. Oocyte size, fecundity and reproductive effort were measured from gravid females collected immediately before spawning. Proxy measures of stream productivity, flow variability and predation pressure were extracted from modelled data sets. A suite of different egg sizes were identified across species within the Galaxias vulgaris complex, with mean oocyte volume differing by up to 133% between species. The species with the smallest eggs showed mean size‐relative fecundities 246% higher than the species with the largest eggs. A significant negative relationship was found between species’ mean egg size and size‐relative fecundity, suggesting a trade‐off between these traits. Species with larger eggs had larger maternal body size, lower reproductive effort and delayed maturity compared to ‘small‐egg’ species. Consistent with the predictions of life‐history theory, species with larger eggs, lower size‐relative fecundity, lower reproductive effort and delayed maturity were associated with low productivity, stable streams, whereas species exhibiting the opposite set of traits occurred in relatively productive but disturbed systems.     

杭州湾北部海域凤鲚个体繁殖力初步研究

于2020年5—8月对杭州湾北部海域凤鲚的繁殖力和生物学指标进行了调查和研究。结果表明:5—8月杭州湾凤鲚产卵群体的平均体长(L)和体质量(W)分别为(163.13±24.02) mm和(11.34±5.40) g,体质量(W)与体长(L)呈幂函数正相关,W=0.000 002L3.087 5(R²=0.925);5—8月杭州湾凤鲚的个体绝对繁殖力平均为(11 683±5 480)粒,个体绝对繁殖力(F)、个体相对繁殖力(FL,FW)与体长(L)、体质量(W)、净体质量(W₂)均呈线性正相关;5—8月凤鲚的平均卵径为(0.707±0.085)mm,各月份之间存在极显著性差异(P＜0.01),其中6月份卵径最大,7月份卵径最小。