Evolutionary and preservational constraints on origins of biologic groups: divergence times of eutherian mammals

Some molecular clock estimates of divergence times of taxonomic groups undergoing evolutionary radiation are much older than the groups' first observed fossil record. Mathematical models of branching evolution are used to estimate the maximal rate of fossil preservation consistent with a postulated missing history, given the sum of species durations implied by early origins under a range of species origination and extinction rates. The plausibility of postulated divergence times depends on origination, extinction, and preservation rates estimated from the fossil record. For eutherian mammals, this approach suggests that it is unlikely that many modern orders arose much earlier than their oldest fossil records.     

Species selection maintains self-incompatibility

Identifying traits that affect rates of speciation and extinction and, hence, explain differences in species diversity among clades is a major goal of evolutionary biology. Detecting such traits is especially difficult when they undergo frequent transitions between states. Self-incompatibility, the ability of hermaphrodites to enforce outcrossing, is frequently lost in flowering plants, enabling self-fertilization. We show, however, that in the nightshade plant family (Solanaceae), species with functional self-incompatibility diversify at a significantly higher rate than those without it. The apparent short-term advantages of potentially self-fertilizing individuals are therefore offset by strong species selection, which favors obligate outcrossing.     

Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia)

Viviparity is known in several clades of Mesozoic aquatic reptiles, but evidence for it is lacking in the Plesiosauria. Here, we report a Late Cretaceous plesiosaur fossil consisting of a fetus preserved within an adult of the same taxon. We interpret this occurrence as a gravid female and unborn young and hence as definitive evidence for plesiosaur viviparity. Quantitative analysis indicates that plesiosaurs gave birth to large, probably single progeny. The combination of viviparity, large offspring size, and small brood number differs markedly from the pattern seen in other marine reptiles but does resemble the K-selected strategy of all extant marine mammals and a few extant lizards. Plesiosaurs may have shared other life history traits with these clades, such as sociality and maternal care.     

竹醋铜制剂对烟株生长发育的影响

为筛选绿色药肥制剂应用于烟叶生产,采用随机区组试验研究竹醋铜制剂不同稀释浓度处理对烤烟农艺性状、干物质积累、叶绿素含量及净光合速率等指标的影响。结果表明:大田喷施竹醋铜制剂200~400倍液可明显改善烟株生长发育,低于100倍液则产生抑制效果。其中,400倍液能够显著提高烟叶的净光合速率,促进叶片干物质积累,较对照(清水)分别提高62.11%和18.33%;同时其株高和茎围分别比对照增加26.10%和19.01%,但是对叶片的叶绿素含量影响不明显。     

潮虫消耗木本植物凋落物的可选择性试验

近年来,越来越多的学者关注外来植物入侵对土壤生态功能的影响效应及其相应反馈机制的探索与研究,然而本地原生土壤生物群落对不同入侵程度下的外来植物种以及本地原生植物种之间是否存在消耗差异却尚不明了.通过等足目潮虫的选择性喂养试验来测试10个本地种、5个非入侵性外来种和5个强入侵性外来种之间的适口性差异,试图求证外来植物的入侵性是否与植物落叶被消耗率呈现必然联系.数据分析结果显示潮虫对本地种、非入侵性外来种和入侵性外来种的消耗并无显著差异;而潮虫对不同生活型下木本植物的取食却存在显著差异,即灌木消耗率显著高于乔木.其次,通过植物初始性状指标(包括木质素、纤维素、半纤维素、碳、氮含量)与相应消耗率的相关比较,消耗量总体上与植物凋落物的氮含量呈正相关关系(R2 =0.358).由此,研究结论强调植物落叶的降解速率并不一定与植物入侵性或入侵阶段呈绝对相互关连,但是氮含量,抑或各种形式的植物氮元素成分都可能在一定程度上参与并影响着外来植物的入侵进程.     

国外甘蔗育种生物技术研究进展

以细胞工程、基因转移、遗传工程为特征的生物技术作为生物学研究中的一种必备手段已经得到广泛运用。近年来,澳大利亚和美国等甘蔗种植大国已在基因文库构建,分子标记或基因定位,甘蔗病害分子诊断及转基因甘蔗方面取得了很大的进展。本文就四个方面加以简要介绍,以促进我国甘蔗抗病育种和病害诊断水平的提高。     

拮抗链霉菌No.24菌株发酵条件优化研究

对1株拮抗链霉菌No.24菌株的发酵条件进行了初步研究,确定了其最佳培养基组成及培养条件。单因素发酵试验和正交试验结果表明,碳源以30g/L葡萄糖和30g/L小米最佳,有机氮源以10g/L黄豆饼粉最好,无机氮源以2g/L(NH4)2SO4最好,最适发酵时间为96h,最适发酵培养温度为32℃,最适初始pH值为7.2～7.4,最佳振荡频率为210r/min,装液量为40mL/250mL。     

辽宁省杂交粳稻产量构成及光合生理生态特性研究

对辽宁省4个冠层形态具有一定差异但又具有较高产量水平的杂交粳稻组合与常规水稻品种辽粳294在籽粒灌浆期的光合生理生态特性进行了比较研究。结果表明:杂交粳稻各组合单株产量明显高于常规对照品种,每穴穗数比对照有所降低,每穗颖花数比对照高出很多,结实率和千粒重差别不大;各杂交组合的上功能叶叶面积和群体LAI都高于对照品种,各组合的叶绿素含量和光合速率平均值在灌浆初期与对照品种差别不明显,在水稻灌浆末期,各杂交组合的茎鞘干物质输出率差别较大。     

The ecological context of life history evolution

There is now a good theoretical understanding of life history evolution, and detailed explicit optimality models have been constructed. These present a challenge for empirical work examining some of the assumptions, such as the extent and mechanisms of the costs of growth and reproduction. In addition, there is an obvious need for comparative tests of the models. These tests, properly applied, may be particularly informative because they can deal with multiple independent variables, including ecological variables, and can reveal broad trends against a background of constraints on optima and the rate of evolutionary approach to them. Life histories are the probabilities of survival and the rates of reproduction at each age in the life-span. Reproduction is costly, so that fertility at all ages cannot simultaneously be maximized by natural selection. Allocation of reproductive effort has evolved in response to the demographic impact of different environments but is constrained by genetic variance and evolutionary history.     

两极光温敏感型小麦雄性不育系337S的选育

地理远缘的普通小麦CIM 89- 1- 11和“84 0 3”杂交后分离出不育株 ,以此为基础育成了既对短日低温敏感 ,又对长日高温敏感的两极光温敏感型雄性不育系 3 3 7S。该不育系不育株率 10 0 % ,在短日低温或长日高温条件下 ,不育度达到或接近 10 0 % ;异交结实率及杂种结实率均可达 85 %以上 ;杂种优势强 ,综合性状好 ,具有良好的应用前景     

极端高温天气条件对鲜食玉米/大豆带状复合种植模式下不同鲜食玉米品种生长的影响

为科学遴选适宜鲜食玉米/鲜食大豆带状复合种植的耐密、抗病、抗倒的鲜食玉米品种,为玉米大豆带状复合种植技术示范推广提供品种支撑。开展了11个鲜食玉米品种与鲜食大豆的带状复合种植试验。结果表明：在2022年夏季极端高温且持续时间较长的气候条件下,夏播不同鲜食玉米品种在双穗率、空秆率等植株性状及千粒鲜重、出籽率、结实率等产量性状上差异明显,其中晶白甜糯、虞珑糯1612、苏玉糯5号、苏科糯1801、苏科糯1901等5个品种结实率较高,表现出较强的耐高温能力;苏甜糯818、斯达糯41、扬甜糯104结实率较低,表现出较低的耐高温能力。     

植物与有益微生物互作的分子基础及其应用的研究进展

植物与微生物在长期的侵染和抗侵染过程中逐渐形成了复杂的互作关系,二者相互利用、协同进化。一些病原微生物致病能力的变化或增强迫使植物提高抗病性,同时改进了植物的农艺性状、产量性状和品质性状。植物与微生物互作关系的分子生物学研究促进了植物基因工程育种途径的创立和生产潜力的提高,尤其微生物介导的基因转移已成为改良植物的重要工具。本文概括性综述了植物与一些主要有益微生物互作的应答反应、信号传导和分子基础,以及利用有益微生物对改良植物性状和生产水平的研究进展。描述了植物对主要有益微生物的应答途径,以及植物和农杆菌、根瘤菌、真菌及植物病毒互作的分子信号系统,并介绍了它们在基因工程、遗传育种和生产实践中的应用。对于人们正确认识有益微生物的两面性,改变传统观念,进一步利用有益微生物的正向作用提高植物抗病性、抗逆性、品质和生产潜力,培育优良作物品种等,具有一定参考价值。     

Comparing Immature Development and Life History Traits in Two Coexisting Host-Feeding Parasitoids,Diglyphus isaea and Neochrysocharis formosa (Hymenoptera: Eulophidae)

Coexisting natural enemies that share a common host resource in the same guild usually exhibit variation in their life history traits, due to their need to share a similar ecological niche. In this study, we compared the immature development times and adult life history traits of two coexisting, host-feeding parasitoids, Diglyphus isaea Walker and Neochrysocharis formosa Westwood (Hymenoptera: Eulophidae), of which both attack larvae of the same agromyzid leafminers. These two species are both synovigenic, idiobiont parasitoids, whose adults consume host fluids (“host feeding”) and lay anhydropic eggs. Of the two, D. isaea has a larger body but little or no initial egg load, and engages in similar lifetime host-feeding events. However, it achieves higher fecundity, longer adult longevity, and higher host suppression ability than N. formosa, which has a smaller body and higher initial egg load. Although D. isaea engages in similar lifetime host-feeding events with N. formosa, all of its gains in life history traits per host-feeding event of D. isaea were larger than those of N. formosa. The age-specific fecundity and host mortality curves of N. formosa were more skewed in early life than those of D. isaea. In addition, the ovigeny index of N. formosa was negatively correlated to body size. Our results confirmed that two coexisting parasitoids, which share the same host resource, show different immature development patterns and life history traits, suggesting that different resource allocation mode could be a general rule of coexisting species sharing the same habitat or host.     

茶树在盆景艺术中的应用研究

茶树具有品种繁多、姿态多样、花期长、可花果同赏、易造型、易繁殖、抗性强、特异资源丰富等特点,是为制作盆景的优良素材,近年来,茶树的观赏价值逐渐被人们重视和利用。笔者从茶树的植物学特征和生物学特性入手,分析茶树应用于盆景艺术中的可行性,从历史性、自然美和功能美等方面对茶树盆景的审美价值进行研究,并阐释其开发价值。     

Constraint to adaptive evolution in response to global warming

We characterized the genetic architecture of three populations of a native North American prairie plant in field conditions that simulate the warmer and more arid climates predicted by global climate models. Despite genetic variance for traits under selection, among-trait genetic correlations that are antagonistic to the direction of selection limit adaptive evolution within these populations. Predicted rates of evolutionary response are much slower than the predicted rate of climate change.     

北京地区园林植物历史引种栽植

植物是进行农业生产、城乡环境建设等工作的重要物质元素,园林植物具有一定的观赏价值,能够美化环境并丰富人们的生活,植物引种驯化在丰富北京地区园林植物资源的同时,也促进了植物文化的交流和传播。在对北京植物资源情况进行分析的基础上,对引种栽植于北京地区的园林植物进行考证和分析,梳理出北京地区常见园林植物的引种栽植历史和园林应用情况,以期为今后植物文化的深入研究提供基础,同时为今后植物的引种驯化提供可借鉴的历史经验。     

Invasion biology of the cotton mealybug,Phenacoccus solenopsis Tinsley: Current knowledge and future directions

The cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), which is native to North America, emerged as a major invasive insect pest of multiple crops in Asia at the beginning of the 21st century. Considering the economic significance of this insect and its rapid worldwide spread, we examined the possible factors driving its invasions. In this paper, we summarize the life history traits of P. solenopsis conceivably related to population development in invaded regions; these traits include its use of diverse host plants, reproductive capacity and mode, adaptation to temperature, response to food shortage, and insecticidal resistance. Then, focusing on the multiple trophic interactions that may promote or hinder invasion, we review the mutualistic relationship of this mealybug with ants and predation and parasitism by natural enemies. Finally, we suggest topics for future research and provide our perspective on the biological invasions of this mealybug. We speculate that specific biological factors associated with this mealybug, particularly its wide host range, high reproductive potential, evolved changes in life history traits, and mutualism with ants have played important roles in its invasions, allowing this pest to become established and rapidly increase its population upon its introduction into new regions.     

猕猴桃品种引种试验

在陕西关中地区对引进的21个猕猴桃品种建立试验园,经过连续6年观察、鉴定,结果表明,美味猕猴桃品种在当地长势较强,较中华猕猴桃品种的果个大、产量高、成熟晚、货架期长。美味猕猴桃品种中海沃德、米良1的综合性状较好,海沃德品种果个大而美观,风味酸甜,丰产,货架期长,但生长季前期抗风力较弱;米良1品种果个大而整齐,风味酸甜,抗逆性强,极丰产,货架期较长;蒙迪和徐香品种的果实风味均优,但果个偏小,货架期短。中华猕猴桃品种在高温干旱年份易出现早期落叶,果实风味较美味猕猴桃偏甜,金丰、金阳1、江园1的综合性状相对较好,果实风味酸甜或甜,产量水平丰产或中等,货架期中等或较短。     

Rates of evolution in ancient DNA from Adélie penguins

Well-preserved subfossil bones of Adélie penguins, Pygoscelis adeliae, underlie existing and abandoned nesting colonies in Antarctica. These bones, dating back to more than 7000 years before the present, harbor some of the best-preserved ancient DNA yet discovered. From 96 radiocarbon-aged bones, we report large numbers of mitochondrial haplotypes, some of which appear to be extinct, given the 380 living birds sampled. We demonstrate DNA sequence evolution through time and estimate the rate of evolution of the hypervariable region I using a Markov chain Monte Carlo integration and a least-squares regression analysis. Our calculated rates of evolution are approximately two to seven times higher than previous indirect phylogenetic estimates.     

长果桑与桑树栽培品种远缘杂交F1代的植物学性状表现分析

[目的]分析长果桑与桑树栽培品种远缘杂交F_1代的植物学性状表现,为桑树远缘杂交的亲本选择提供参考。[方法]按照长果桑×桑树栽培品种和桑树栽培品种×长果桑2种远缘杂交类型配置杂交组合,每种杂交类型配置5个杂交组合,授粉、采种、育苗后栽植,调查叶片、枝条的主要植物学性状表现。[结果]在长果桑×桑树栽培品种和桑树栽培品种×长果桑2种远缘杂交类型中,各组合亲本均无椭圆形叶,F_1代均有椭圆形叶植株,平均比例分别为13.28%和10.48%;亲本无短尾叶尖的杂交组合,F_1代出现短尾叶尖植株的平均比例分别为29.88%和24.94%;亲本无钝头叶尖的杂交组合,F_1代出现钝头叶尖植株的平均比例分别为14.16%和11.86%。亲本无弯曲枝条的杂交组合,F_1代出现弯曲枝条植株的平均比例分别为26.83%和32.66%;亲本无折曲节间的杂交组合,F_1代出现折曲节间植株的平均比例分别为23.72%和18.28%。[结论]长果桑与桑树栽培品种远缘杂交F_1代的植物学性状表现丰富,出现了很多亲本中没有的性状,可以从中选择符合需要的植株开展材料创新和品种选育。