Effects of temperature and salinity on the asexual reproduction of Aurelia coerulea polyps

Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.

Photosynthesis-Dependent Extracellular Ca2+ Influx Triggers an Asexual Reproductive Cycle in the Marine Red Macroalga Porphyra yezoensis

Asexual propagation to increase the number of gametophytic clones via the growth of asexual haploid spores is a unique survival strategy found in marine multicellular algae. However, the mechanisms regulating the asexual life cycle are largely unknown. Here, factors involved in the regulation of production and discharge of asexual spores, so-called monospores, are identified in the marine red macroalga Porphyra yezoensis. First, enhanced discharge of monospores was found by incubation of gametophytes in ASPMT1, a modified version of the previously established synthetic medium ASP12. Comparison of the compositions of ASPMT1 and our standard medium, ESL, indicated that the Ca2+ concentration in ASPMT1 was three times lower than that in ESL medium. Thus, we modified ASPMT1 by increasing its Ca2+ concentration, resulting in reduction of monospore discharge. These findings demonstrate the role of reduced Ca2+ concentrations in enhancing monospore production and release. Moreover, it was also observed that initiation of asexual life cycle required illumination, was repressed by DCMU, and was induced by a Ca2+ ionophore in the dark. Taken together, these results indicate that photosynthesis-dependent Ca2+ influx triggers the asexual life cycle by promoting the production and discharge of monospores in P. yezoensis.

The putative elongator complex protein Elp3 is involved in asexual development and pathogenicity by regulating autophagy in the rice blast fungus

Autophagy is responsible for maintaining fundamental cellular homeostasis and is,therefore,essential for diverse development processes.This study reported that PoElp3,the putative catalytic subunit of Elongator complex,is involved in the maintenance of autophagy homeostasis to facilitate asexual development and pathogenicity in the rice blast fungus Pyricularia oryzae.It was found that the ΔPoelp3 strains were defective in vegetative growth,conidiation,stress response,and pathogenicity.The mutants exhibited hyper-activated autophagy in the vegetative hyphae under both nutrient-rich and nutrient-deficient conditions.The hyper-activation of autophagy possibly suppressed the production of vegetative hyphae in the ΔPoelp3 strains.Moreover,the ΔPoelp3 strains were found to be more sensitive to rapamycin during vegetative-and invasive-hyphal growth but have no effect on Target-of-Rapamycin(TOR)signaling inhibition.Taken together,these results demonstrated that PoElp3 is involved in asexual development and pathogenicity by regulating autophagy in the rice blast fungus.

Vegetative Compatibility and Asexual Recombination in Magnaporthe grisea from Jiangsu Province, China

Vegetative compatibility among isolates of different races in Magnaporthe grisea collected from Jiangsu Province and asexual recombination among compatible isolates by anastomosis were tested. Twenty isolates involving seven races from diseased rice plants were paired on polished rice rose bengal medium and incubated at 25℃ in darkness for 18 days. Among 173 pairings tested, solid hyphal fusion lines formed by anastomosis between 124 pairings, indicated that these isolates were vegetative compatible with each other. The result showed that most M. grisea isolates were vegetative compatible. Furthermore, 17 vegetative compatible pairings between monoconidial isolates with MBCsIPTr marker and isolates with MBCrIPTs marker were selected to detect the asexual recombination between the compatible isolates of different races. The asexual recombinants with MBCrIPTr marker were detected in single hyphal fragment progenies in thirteen of the seventeen pairings. The percentage of recombinants was about 0. 6 -11.3%. Results showed that vegetative compatibility was prevailing among isolates of M. grisea in Jiangsu Province in vitro. These results also suggested that asexual recombination may be an important mechanism for M. grisea to maintain genetic diversity in nature.

<i>In Vitro</i >Culture of <i>Plasmodium falciparum</i>: Obtention of Synchronous Asexual Erythrocytic Stages

Cultivation of the erythrocytic stages of Plasmodium parasites, specifically the most important and deadly for humans, Plasmodium falciparum, has required a lot of effort and time in order to develop a continuous in vitro culture. Moreover, the development of methods to synchronize P. falciparum parasites (which grow asynchronously in vitro) has become an essential tool in research to study different immulogical, biochemical or physiological aspects of the parasite. We have compared two different synchronization methods, one based on differential permeability of the membrane of parasitized erythrocytes, and the other on the sedimentation behavior in gelatin solution. An optimized method has been established which allows for maintaining a healthy, highly synchronous culture for longer periods of time. Asexual erythrocytic stages of a complete P. falciparum cycle have been obtained, which is the starting point of the stage-specific assays of the activity of new antimalarial drugs.

Variation in reproductive life-history traits of Chinese Bulbuls(Pycnonotus sinensis)along the urbanization gradient in Hangzhou,China

Urbanization brings new selection pressures to wildlife living in cities,and changes in the life-history traits of urban species can reflect their responses to such pressures.To date,most of the studies investigating the impacts of urbanization on avian life-history traits are conducted in Europe and North America,while such studies are often lacking in quickly developing countries in Asia(e.g.,China).In this study,we examined the variations in reproductive life-history traits of Chinese Bulbuls(Pycnonotus sinensis)along the urbanization gradient in Hangzhou,China.We detected 234 natural nests of Chinese Bulbuls and continuously monitored them in two continuous breeding seasons from 2012 to 2013.We collected data on seven life-history traits(laying date,incubation period,nestling period,clutch size,egg volume,hatching success rate,and fledging success rate).We used infrared cameras to record the number of feedings per hour as the measure of food resources for the nestlings.We measured nest predation pressure by monitoring 148 natural breeding nests during breeding seasons and 54 artificial nests immediately after breeding seasons.We then calculated the urbanization synthetic index(USI)as a measure of the level of urbanization and examined its relationship with the seven life-history traits.We found that Chinese Bulbuls laid eggs significantly earlier with increasing USI.However,the other six life-history traits did not vary significantly with the USI.Moreover,the feeding frequency of chicks increased significantly with the USI,but the nest predation pressure of Chinese Bulbuls decreased significantly with the USI.Increased food resources and reduced nest predation pressure in cities may lead to earlier laying date of Chinese Bulbuls.Further study should test whether the earlier laying date of Chinese Bulbuls is the result of phenotypic plasticity or genetic change.

Effect of Tree Species and Dosage of Rhizomorph Wood on Asexual Propagation of Wild Gastrodia elata. Bl. f. glauca S. Chow in Ganzi

The effects of the tree species and the dosages of Armillariella mellea rhizomoph wood on asexual propagation of wild Gastrodia elata Bl. f. glauca S. Chow were studied in Ganzi prefecture. The results showed that tree species had a very significant effect on asexual reproduction yield of wild Gastrodia elata Bl. f. glauca S. Chow. The drying rate and yield of Gastrodia elata Bl. f. glauca S. Chow cultured by close grained woods such as Quercus spinosa David ex Fr. was extremely significant higher than that cultured by coarse grained wood such as Betula platyphylla Suk. The dosage had a very significant effect on the yield of wild Gastrodia elata Bl. f. glauca S. Chow whereas it had no influence on the drying rate.

Influences of Different Habitats on Asexual Propagation of Wild Gastrodia elata f. glauca being Domesticated in Ganzi

[Objective] The influences of different habitats on asexual propagation of wild Geg(abbreviation for Gastrodia elata Bl. f. glauca S. Chow) being domesticated in Ganzi prefecture was studied. [Method] The research trial was carried out in the following three kinds of habitats at the same time: the plastic greenhouses, the birch forest of shady slope and the shrubbery of sunny slope, and the results were analyzed with group data average hypothesis test method. [Result] The overall tuber(the juvenile tuber, the immature tuber and the mature tuber) yield and the mature tuber yield were both very significantly higher in the plastic greenhouses than in the other two types of habitats, and respectively reached 9.52 and 6.70 kg/m2; the mature tuber drying rate was dramatically or very dramatically lower in the plastic greenhouses than in the other two types of habitats, and was 23.84%; the stabilities of the overall tuber yield, the mature tuber yield and the drying rate were all reduced in the order of greenhouses, birch forest and shrubbery; and the dry mature tuber yield of the plastic greenhouses was the highest in the three kinds of habitats, and was 1.60 kg/m2. [Conclusion] A good habitat had to be created or chosen in the domesticating cultivation of the wild Geg in Ganzi prefecture. The preferred choice was the plastic greenhouse, the alternative one was the deciduous broadleaved forest of shady slope. The imitating wild planting of the wild Geg should be done in the warm moist deciduous broad-leaved forest of shady slope.

药食两用植物黑老虎组培快繁体系研究

为改变药食同源植物黑老虎野生资源日趋减少、难以满足市场需求的现状,对组培快繁体系中的培养基配制及组培瓶苗培育条件进行了研究,以期建立黑老虎组培快繁体系,为规模化种苗繁殖奠定基础。结果表明,以MS+2.0 mg/L 6-BA+0.2 mg/L NAA为初代培养基,以B5+2.0 mg/L 6-BA+0.2 mg/L NAA为增殖培养基,以1/2 MS+0.1 mg/L 6-BA+1.5 mg/L NAA+0.3%活性炭为生根培养基,先暗培养,再光照培养,生根率可达100%,且小苗主根粗,长势强。组培苗最佳炼苗时间为15 d,最佳移栽基质为塘泥∶蔗渣∶鸡粪∶过磷酸钙=3.9∶4∶2∶0.1,最佳遮阳模式为半遮阳,最佳培育期为60 d。

莓叶委陵菜叶插繁殖技术研究

莓叶委陵菜(Potentilla fragarioidis)作为我国北方地区极具开发潜力的乡土地被植物,存在着有性繁殖材料不易获得且繁殖系数较低的问题。而扦插繁殖作为一种无性繁殖手段,能为莓叶委陵菜的快速繁殖提供新的途径。本研究以莓叶委陵菜生长健壮、无病虫害的叶为试验材料,通过正交试验针对不同扦插基质、激素种类及其浓度对莓叶委陵菜叶插生根效果的影响进行探究。结果表明,莓叶委陵菜插穗在扦插45 d后能够形成根系,不同处理水平的扦插基质、激素种类及其浓度间的交互效应对插穗生根效果的影响具有显著差异(P<0.05)。扦插基质是影响莓叶委陵菜叶插生根率的主导因子,而激素种类是影响平均单株生根数、平均单株总根长、最长根长和根系效果指数的主要因素。以草炭+珍珠岩+蛭石(1:1:1)为基质,扦插前使用300 mg·L^(-1)的IBA对插穗进行处理生根效果最佳,该处理方式下扦插生根率达63.33%,平均单株生根数为6.90条,平均单株总根长为27.98 cm,最长根长13.83 cm,根系效果指数达20.50。本研究结果可为莓叶委陵菜无性系繁殖体系的快速建立提供理论依据。

牛樟树水提物中促进樟芝无性产孢的效应物鉴定及其添加量优化

为明确牛樟树水提物(aqueous extract of Cinnamomum kanehirae Hay,CWE)中促进樟芝(Antrodia cinnamomea)深层发酵无性产孢的效应物。首先,采用醇沉法及不同有机溶剂分级萃取法对CWE进行分离,并以产孢量为检测指标,考察不同组分对樟芝无性产孢的影响。结果表明,30μg/mL的CWE醇沉上清氯仿萃取物LFE和50μg/mL的醇沉上清乙酸乙酯萃取物YZE对樟芝无性产孢有明显的促进效果,且LFE的促进效果明显优于YZE,表明效应物主要存在于LFE和YZE中。随后,采用液相色谱-质谱联用仪对CWE不同萃取组分进行成分分析,并结合不同组分对樟芝产孢的影响效果,确定主要效应物为赤藓糖醇。最后,考察赤藓糖醇(纯度98%)对樟芝深层发酵性能的影响,结果表明,赤藓糖醇对樟芝无性产孢有显著促进效果,且在最佳添加量(1.0μg/mL)下,产孢量较对照组提高55.17%;同时,1.0μg/mL赤藓糖醇显著促进樟芝深层发酵菌丝体生长及胞内多糖的合成,生物量和胞内多糖产量较对照组分别提高18.65%和260.13%,但对三萜的合成无显著影响。

闭鞘姜组培快繁技术研究

为了解决闭鞘姜种苗繁殖效率低的问题,研究组培快繁无性繁殖技术。以闭鞘姜茎段为外植体,经初代培养、继代培养和生根培养发育成无菌试管苗。结果表明:1/2MS+0.5~1.0 mg/L 6-BA培养基诱导出芽效果较好,出芽率达到81.11%;MS+0.5 mg/L NAA+2.0~3.0 mg/L 6-BA培养基增殖效果较好,增殖率达到3.67倍;MS+0.2 mg/L 6-BA和2~4mg/L NAA培养基壮苗生根效果较好,苗长达到8.07 cm,根数达到6.35条。该技术体系为闭鞘姜种苗快繁提供了新的技术途径。

A preliminary study on life history of marine red alga Stylonema alsidii(Zandardini)Drew f.ramosum Zheng et Li

Stylonema alsidii(Zandardini)Drew f.ramosum Zheng et Li is a common species in the genus Stylonema,but there are limited reports on morphological taxonomy and a lack of studies on life history and the regulation of early development.The early development,discoid formation,and erect thallus growth of Stylonema alsidii f.ramosum were observed under laboratory conditions.In addition,the influence of main environmental factors such as temperature and light intensity on its development was briefly studied,and various stages of its life history were observed.The result shows:(1)there are two reproductive modes:asexual reproduction and sexual reproduction;(2)the morphology of this species varies in different degrees under laboratory culture conditions;(3)sexual reproduction and asexual reproduction can coexist under suitable conditions.Five pathways of life history were inferred from experimental phenomena.Mature sporophytes form mature gametophytes by producing initially isolated or initially attached monospore,and mature gametophytes form mature sporophytes by fertilization of eggs and sperms.The sexual and asexual reproduction processes of Stylonema alsidii f.ramosum were reported for the first time,and this is also the first report on sexual reproduction in the genus Stylonema.

国家二级保护植物降香黄檀繁育技术研究进展

降香黄檀(Dalbergia odorifera T.Chen)为豆科黄檀属常绿半落叶乔木,仅天然分布于海南岛,现为国家二级保护植物。它既是中国重要的战略资源,又是特有的名贵药材和香料树种。由于人类不合理的采伐以及大量的盗伐,降香黄檀的野生资源几近枯竭。同时,全球范围内降香黄檀的销售一直以来出现供不应求的现象,这也导致降香黄檀的市场价格持续攀升,已经达到“以斤计价”、“稀缺难寻”的地步。此外,降香黄檀心材在野外自然条件下的形成时间也比较漫长,一般7年左右才开始形成心材,而成熟需要30年以上的漫长时间。因此,开展降香黄檀繁育技术研究,不仅可以满足不断增长的市场需求,还可以减轻对其残留天然资源的盗伐压力。近年来,国内外学者对降香黄檀的繁育技术进行了大量研究,并取得了丰硕成果。基于此,文章从有性繁殖(种子萌发、幼苗生长)、无性繁殖(扦插、嫁接、组织培养)以及人工林定向培育(注射生长调节剂、接种微生物、种植管理措施)等方面,综述了降香黄檀繁育技术的研究进展;同时分析了降香黄檀产业发展中存在的主要问题,如优良种质资源不足、高效栽培技术和定向培育技术缺乏、新品种物质基础研究不足、活性成分挖掘不系统等,提出了加大新品种选育工作力度、创新栽培技术体系以及突破产业链结构升级等研究展望,以期为降香黄檀的优质种苗繁育技术研究提供参考。

基于自主品种提升农业产值的“植物的生殖”教学设计

在“植物的生殖”教学中,以月季花新品种的开发和大规模推广为主线,学习植物有性生殖和无性生殖的方式,了解不同繁殖方式在农业生产中的应用及价值,培养学生的态度责任和探究实践能力。

红锥扦插生根剂优化试验

以红锥超级苗作为采穗母株,分析了红锥扦插生根过程中插穗中内源激素吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GAs)、玉米素苷(ZR)水平及16种生长调节剂处理下扦插育苗效果的变化。研究结果表明:在0~60 d扦插生根过程中,随着扦插时间延长,IAA水平呈先上升后下降,GAs水平呈先下降后上升的趋势,ABA水平在扦插15 d增加,而后在扦插30~60 d减少并保持在一个较为稳定的水平,ZR无明显变化。在以外源性类生长素物质0~400 mg·L^(-1)IAA、萘乙酸(NAA)、吲哚丁酸(IBA)及0~200 mg·L^(-1)GAs合成抑制剂多效唑(PBZ)、缩节胺(DPC)组成的16种不同配比生根剂处理下,生根率差异显著(0%~94.8%,P<0.05)。通过极差值(R)分析发现,DPC(32.3)>NAA(28.5)>IBA(25.6)>PBZ(23.5)>IAA(10.9)。扦插成活率与生根率无明显相关性(R 2=0.51,P>0.05),但与根条数呈显著的正相关线性关系(R 2=0.91,P<0.05)。穗条木质化程度影响扦插育苗效果,相较初木质化和木质化穗条,半质化穗条生根率、根条数、成活率变幅较小,并以200 mg·L^(-1)NAA+200 mg·L^(-1)IBA+100 mg·L^(-1)PBZ+100 mg·L^(-1)DPC处理下扦插育苗效率最高(95.4%)。研究认为,以半木质化穗条为插穗,200 mg·L^(-1)NAA+200 mg·L^(-1)IBA+100 mg·L^(-1)PBZ+100 mg·L^(-1)DPC为生根剂,可获得较好的扦插效果。

Effects of life-history components on population dynamics of the rare endangered plant <i>Davidia involucrata</i>

In order to estimate the most effect stage and process on population growth and effective conserve the rare endangered plant Davidia involucrata, we analyzed the dynamics and the contributions of life-history components on population dynamics based on Lefkovitch matrix model and sensitivity analysis. The life cycle of Davidia involucrata was divided into six stages (seed, seedling, juvenile, immature, early adult and late adult) based on the species characteristics and published literature data, the survival rates in each life-history stage were simulated using a static life table, and the fecundity of each stage was determined according to sample information. The results showed that the structure of the observed population was not ideal, and the numbers of seedlings and coppice shoots was similar. The population growth rate was influenced largely by individual growth process, and asexual reproduction made a larger contribution to population growth than sexual reproduction. However, sexual reproduction was more important than asexual reproduction, because most asexual reproducing individuals (the coppice shoots) were derived mainly from human destruction (e.g. felling trees). The most important stage was stage V (late adult), associated with seed production and germination. Therefore, conservation of Davidia involucrata populations should focus on stage V and sexual reproduction, in order to improve the seed production and germination rate, and to promote population stability and development.

重庆乡土核桃无性系坚果品质分析

对6个重庆乡土核桃无性系的坚果品质进行分析与评价,为重庆优良核桃品种的选育提供一定的理论依据.采用方差分析、多重比较、主成分分析等方法对参试核桃无性系坚果的单果质量、三径均值、出仁率、脂肪、蛋白质以及脂肪酸组分等16项指标进行了测量、分析和综合评价.结果表明:核桃坚果的三径均值(28.45~35.16 mm)、单果质量(6.85~15.18 g)、壳厚(0.96~1.32 mm)、出仁率(50.00%~60.25%)、蛋白质(17.07%~24.23%)、脂肪(54.40%~67.63%)、可溶性糖(4.47%~7.95%)、单宁(10.50~25.40 mg/g)以及检测出的8种脂肪酸组分的质量分数在参试无性系间存在差异,所有参试无性系的出仁率、蛋白质质量分数、脂肪质量分数均达到国家良种标准.6个无性系的主成分综合得分由高到低依次为YC-8,YC-3,YC-10,YC-6,YC-12,YC-2.基于重庆乡土核桃无性系坚果品质特点,探讨了重庆乡土核桃无性系选育利用方向,初步明确了YC-8可作为综合性状优的干食核桃无性系,YC-3可作为高出仁率的干鲜两用核桃无性系,YC-10可作为高蛋白核桃无性系.

Covariation in Insular Life-history Traits of the Rice Frog(Fejervarya limnocharis)in Eastern China

Although shifts in life-history traits of insular vertebrates, as compared with mainland populations, have been observed in many taxa, few studies have examined the relationships among individual life-history traits on islands. Lifehistory theory also predicts that there is a trade-off between body size and reproductive effort, and between egg size and clutch size. We surveyed the rice frog, Fejervarya limnocharis, on 20 islands within the Zhoushan Archipelago and two nearby sites on the mainland of China to compare differences in life-history traits and to explore relationships among those traits. Rice frog females reached a greater body size on half of the smaller islands among the total 20 surveyed islands, and larger egg size, decreased clutch size and reduced reproductive effort on most of the islands when compared to the two mainland sites. Insular body size was negatively correlated with reproductive effort. There was a negative correlation between egg size and clutch size. Results suggest that life-history theory provides a good explanation for co-variation between body size and reproductive effort, and between egg size and clutch size in rice frogs on the islands.

小麦条锈菌ZS有性与无性菌系毒性差异初步分析

小麦条锈病是小麦生产上最主要的病害,条锈菌毒性不断变异是造成小麦条锈病频繁发生和小麦品种抗病性丧失的主要原因。对小麦条锈菌新菌系开展品种抗病性评价,并探明条锈菌有性菌系、无性菌系间的毒性差异,为科学、超前指导小麦抗病育种和抗病品种的合理布局应用提供技术支撑。2017—2021年从454个小麦条锈菌有性菌系和1728个无性菌系中,获得ZS有性菌系35个和无性菌系167个,占比分别为7.71%和9.66%;其中已归类ZS-1、ZS-18、ZS-52类型中有有性菌系14个、无性菌系72个,占比分别为3.08%和4.17%。2022年选择ZS有性与无性菌系重要类型混合菌,对76个甘肃省内小麦生产品种进行苗期、成株期接种鉴定,结果发现,有性ZS菌系与无性ZS菌系对供试小麦品种苗期致病力分别为97.37%、92.11%,相对寄生适合度分别为0.3530、0.2487;成株期致病力分别为72.37%、71.05%,相对寄生适合度分别为0.3627、0.1840。表明有性菌系致病性和寄生适合度均高于无性菌系。建议在陇南越夏区,及早调整小麦抗病育种目标,以持续控制条锈病的发生流行,保障粮食安全。