狭叶坡垒传粉生物学初探

狭叶坡垒(Hopea chinensis)为常绿乔木,是我国热带季雨林的代表树种之一。它树型优美,具一定的耐寒性,是我国珍稀濒危保护植物。为阐明其传粉生物学特征和迁地保护的繁殖潜力,该文在引种地桂林植物园对狭叶坡垒的开花物候、花尺寸和花气味进行了观察和测量,运用杂交指数(OCI)、花粉胚珠比(P/O)、花粉活力、柱头活性检测和人工自交等方法对其繁育系统进行了检测,观察了访花昆虫并检验了其传粉效率,通过人工异交检验了繁殖潜力和可能的传粉限制。结果表明:(1)桂林植物园内狭叶坡垒的花期为7月底到9月底,持续60 d左右,一个花序花期约12 d,单花期约3 d,花朵开放时间为17:00—18:45。(2)雌雄同熟,雌蕊空间位置高于雄蕊,高花粉活力和高柱头可授性出现时间基本一致。(3)OCI 等于4,P/O为10 788±984。(4)无自动自花授粉能力且自交不亲和,自然条件下和异交授粉能坐果且坐果率无显著差异。(5)蕈蚊是狭叶坡垒唯一的传粉者。(6)主要花香成分为β-榄香烯、(E)-7,11-二甲基-3-亚甲基-1,6,10-十二碳三烯和1-石竹烯。综上所述,狭叶坡垒繁育系统为异交,在迁地保护地需要蕈蚊作为传粉者,能坐果并得到成熟种子,不存在授粉限制。     

睾酮对鸟类繁殖影响研究进展

类固醇激素睾酮是影响鸟类繁殖最重要的性激素之一,与鸟类的繁殖行为的各个方面息息相关。睾酮通过影响鸟类的羽色、鸣声等来影响鸟类的配偶选择,同时睾酮可以调节配偶选择和繁殖投入之间的平衡。睾酮水平影响出雏数、出飞数、孵化率成功率等繁殖成效。睾酮还对个体的免疫活性和个体的存活率等产生影响。目前关于睾酮对鸟类繁殖影响的研究大多是通过外源性植入睾酮的方式来改变个体睾酮的浓度,其研究结果也常出现相互矛盾之处,对于自然状态下影响睾酮水平变化的因素尚缺乏了解,睾酮对雌雄鸟在繁殖过程中的影响也不尽相同,有必要继续深入研究。     

全球中华鲎资源保护现状及对策建议

鲎是古老的海洋节肢动物。中华鲎(Tachypleus tridentatus)是世界现存4种鲎中体型最大的一种, 是河口生态系统的标志物种, 同时其血液被用于生产医用检验试剂――鲎试剂。中华鲎的自然地理分布范围相当狭窄, 仅局限于日本濑户内海向南延伸至印度尼西亚爪哇岛北岸以北的太平洋西岸海域, 其中在中国东岸和日本南部海域的历史产量较高。自20世纪50年代以来中华鲎种群数量出现了显著减少, 2019年中华鲎在IUCN红色名录中的濒危等级正式更新为濒危(EN), 明确了中华鲎资源呈现全球性衰退的状态, 究其原因可归纳为鲎生境破坏和过度捕捞两个方面。在开展鲎资源保护的实践工作中, 作者深刻反思当前鲎资源保护在海洋保护区划定、增殖放流及科普和野生动物保护法宣传中存在的问题并提出相应建议, 包括加快完善种群基线数据, 制定标准化种群和生境基线监测指南, 构建科学放流体系等, 以期推进全球范围内的中华鲎资源保护与科学管理。     

Habitat fragmentation shapes natal dispersal and sociality in an Afrotropical cooperative breeder

It remains poorly understood how effects of anthropogenic activity, such as large-scale habitat fragmentation, impact sociality in animals. In cooperatively breeding species, groups are mostly formed through delayed offspring dispersal, and habitat fragmentation can affect this process in two opposite directions. Increased habitat isolation may increase dispersal costs, promoting delayed dispersal. Alternatively, reduced patch size and quality may decrease benefits of philopatry, promoting dispersal. Here, we test both predictions in a cooperatively breeding bird (placid greenbul, Phyllastrephus placidus) from an Afrotropical cloud forest archipelago. Males born in fragmented forest dispersed about 1 year earlier than those born in continuous forest. Contrary to females, males also started to reproduce earlier and mostly settled within their natal patch. Females only rarely delayed their dispersal for more than 1 year, both in fragmented and continuous forests. Our results suggest that early male dispersal and reproduction is jointly driven by a decrease in the value of the natal territory and an increase in local breeding opportunities in fragmented forest. While plasticity in dispersal strategies of cooperative breeders in response to anthropogenic change is believed to optimize reproduction-survival trade-offs, to what extent it shapes the ability of species to respond to rapid environmental change remains to be studied.     

Genomic and phenotypic effects of inbreeding across two different hatchery management regimes in Chinook salmon

Genomic approaches permit direct estimation of inbreeding and its effect on fitness. We used genomic‐based estimates of inbreeding to investigate their relationship with eight adult traits in a captive‐reared Pacific salmonid that is released into the wild. Estimates were also used to determine whether alternative broodstock management approaches reduced risks of inbreeding. Specifically, 1,100 unlinked restriction‐site associated (RAD) loci were used to compare pairwise relatedness, derived from a relationship matrix, and individual inbreeding, estimated by comparing observed and expected homozygosity, across four generations in two hatchery lines of Chinook salmon that were derived from the same source. The lines are managed as “integrated” with the founding wild stock, with ongoing gene flow, and as “segregated” with no gene flow. While relatedness and inbreeding increased in the first generation of both lines, possibly due to population subdivision caused by hatchery initiation, the integrated line had significantly lower levels in some subsequent generations (relatedness: F₂–F₄; inbreeding F₂). Generally, inbreeding was similar between the lines despite large differences in effective numbers of breeders. Inbreeding did not affect fecundity, reproductive effort, return timing, fork length, weight, condition factor, and daily growth coefficient. However, it delayed spawn timing by 1.75 days per one standard deviation increase in F (~0.16). The results indicate that integrated management may reduce inbreeding but also suggest that it is relatively low in a small, segregated hatchery population that maximized number of breeders. Our findings demonstrate the utility of genomics to monitor inbreeding under alternative management strategies in captive breeding programs.     

Female loggerhead sea turtles (Caretta caretta L.) rarely remate during nesting season

The goal of this study was to assess the consequences of single versus multiple paternity by identifying paternity of clutches per female to identify whether there were detectable costs or benefits. Multiple mating can occur when the benefits of mating outweigh the costs, but if costs and benefits are equal, no pattern is expected. Previous research on loggerhead sea turtle (Caretta caretta) populations found male‐biased breeding sex ratios and multiple mating by many females nesting in southwestern Florida. A sample of nesting loggerhead females who laid more than one nest over the course of the season and a subset of their hatchlings were examined from 36 clutches in 2016 on Sanibel Island, Florida. Males that fathered hatchlings in the first clutch sampled were identified in subsequent clutches. Interestingly, 75% of the females analyzed had mated singly. No male was represented in more than one female's clutches. The results suggest that females likely mate at the beginning of the season and use stored sperm for multiple clutches. Evidence for mating between laying events was limited. There was no consistent pattern across the subsequent multiple paternity clutches, suggesting benefits to loggerhead females likely equal their costs and subsequent mating is likely determined by female preference.     

Tool for genomic selection and breeding to evolutionary adaptation: Development of a 100K single nucleotide polymorphism array for the honey bee

High‐throughput high‐density genotyping arrays continue to be a fast, accurate, and cost‐effective method for genotyping thousands of polymorphisms in high numbers of individuals. Here, we have developed a new high‐density SNP genotyping array (103,270 SNPs) for honey bees, one of the most ecologically and economically important pollinators worldwide. SNPs were detected by conducting whole‐genome resequencing of 61 honey bee drones (haploid males) from throughout Europe. Selection of SNPs for the chip was done in multiple steps using several criteria. The majority of SNPs were selected based on their location within known candidate regions or genes underlying a range of honey bee traits, including hygienic behavior against pathogens, foraging, and subspecies. Additionally, markers from a GWAS of hygienic behavior against the major honey bee parasite Varroa destructor were brought over. The chip also includes SNPs associated with each of three major breeding objectives—honey yield, gentleness, and Varroa resistance. We validated the chip and make recommendations for its use by determining error rates in repeat genotypings, examining the genotyping performance of different tissues, and by testing how well different sample types represent the queen's genotype. The latter is a key test because it is highly beneficial to be able to determine the queen's genotype by nonlethal means. The array is now publicly available and we suggest it will be a useful tool in genomic selection and honey bee breeding, as well as for GWAS of different traits, and for population genomic, adaptation, and conservation questions.     

Doubled Haploid Production Using an Improved Anther Culture Protocol for Sorghum [<i>Sorghum bicolor</i> (L.) Moench]

Sorghum [Sorghum bicolor (L.) Moench] can benefit from accelerated breeding and release of improved varieties through doubled haploid technology. The technology has been used in speeding up the breeding of other major cereals such as wheat, maize and rice, for which generally widely applied optimised protocols exist. A reproducible protocol for the crop, that can overcome genotype dependency and other species-specific challenges such as phenolic exudation is however lacking. This study aimed at sorghum doubled haploids production thereby contributing to the development of an improved protocol. From the 28 hybrid genotypes, both F₁ registered- and experimental hybrids involved, this study successfully produced haploids from five genotypes and subsequently, four confirmed doubled-haploid lines on W14mf medium or its modification with 1.0 gl⁻¹ L-proline, 1.0 gl⁻¹ L-asparagine and 1.0 gl⁻¹ KH₂PO₄. Medium 190-2Cu was used for regeneration and rooting, which occurred successfully, if the calli were transferred on to it less than 7 days after induction, and temperature was maintained at 25˚C under light condition. Genotype dependency was not wholly overcome; however, sorghum’s high tillering ability and abiotic stress tolerance were observed to contribute to attainment of haploid plantlets. Spontaneous diploids producing seeds at rates of upto 80.5% were obtained, therefore eliminating the need for colchicine duplication.     

茜草科二型花柱植物滇丁香传粉精确性研究

异型花柱是一种受遗传因素控制的花型多态性现象,其适应意义在于提高不同花型间传粉精确性,从而促进异交。为检验二型花柱植物滇丁香（Luculia pinceana）是如何促进异交并确定有效传粉者的类型,实验统计自然种群中长、短柱型的植株数量,测量花部特征,统计自然种群植株柱头上的型间花粉落置的数量和比例,比较型内、型间花粉的萌发率以及花粉管长度,比较不同人工授粉处理结实情况,观察传粉昆虫类型并测量虫体特征。结果表明（1）滇丁香自然居群中长、短柱型植株的数量没有显著性差异。长柱型的筒深、筒直径、开口直径、雄蕊长和柱头长均显著小于短柱型,而长柱型的叶片长和宽、雌蕊长、花药体积、花粉粒体积、柱头厚均显著大于短柱型。（2）自然种群植株柱头上型间花粉所占比例显著低于型内花粉的比例。（3）型间授粉的花粉萌发率以及花粉管长度均大于型内授粉和混合授粉。（4）型间授粉的结实率显著高于型内授粉的结实率,型内授粉具有一定的结实。（5）夜行性长喙条背天蛾（Cechenena lineosa）是滇丁香的有效传粉者,其吻长和滇丁香的花筒深相适应。本研究表明二型花柱植物滇丁香主要是通过与其花部特征相匹配的长喙天蛾实现有效的传粉,通过促进型间花粉的萌发和花粉管的伸长而有利于型间授粉结实,提高传粉精确性。