Asexual Reproduction of Aurelia coerulea Polyps in situ on Settling Plates in Jiaozhou Bay,China

Jellyfish blooms are increasingly prevalent coastal phenomena,with Aurelia coerulea being a significant contributor.The complex life history of jellyfish,featuring a sessile polyp stage,is a key factor in bloom formation,yet it is challenging to study in the field.This study aimed to describe the asexual reproduction of A.coerulea polyps in Jiaozhou Bay,China,and to assess their ability to form sedentary colonies and their relationship with environmental factors.Using settling plates,we observed polyps in situ and documented three asexual reproduction modes:budding,strobilation,and podocyst formation.Environmental parameters including temperature,salinity,dissolved oxygen(DO),chlorophyll a(Chl a),and the biomass of phytoplankton and zooplankton were monitored.Budding was the predominant reproductive method,featuring stolon budding in autumn and direct budding during the winter and spring seasons.Strobilation took place in the colder months,releasing ephyrae between April and May.Polyp abundance was positively correlated with seawater temperature and negatively correlated with DO concentration.Polyps at 1.0 m depth showed higher survivorship and proliferation over 8 months,whereas those at 2.0 m depth experienced a steady decline and died within 4 months.The study enhances our understanding of the life cycle and asexual reproduction strategies of A.coerulea polyps in the field,with implications for predicting and managing jellyfish blooms.The findings underscore the importance of temperature and DO in polyp survival and suggest that initial polyp population proliferation is crucial for long-term survival.

Different Responses of Sexual and Asexual Reproduction of Arundinella hirta to Flooding

The sexual and asexual reproductive features of the graminoid species Arundinella hirta growing at riversides of the Jialing River were analyzed.It was found that the total seed mass,seed number per plant,and sexual reproductive allocation of A.hirta decreased with decreasing bank elevation,and plants growing at the lowest elevations of banks subjected to intense flooding did not show sexual reproduction.The total plant biomass and the number of ramifications per plant increased with flooding intensity,which implies that,contrary to sexual reproduction,asexual reproduction of A.hirta was enhanced by flooding.

Scale Breeding and Reproduction Technique of Ficus tikoua Bur.Container Seedlings

Based on the principle of asexual reproduction,a kind of scale breeding and reproduction technique of Ficus tikoua Bur.container seedlings was explored by using the characteristics of strong adaptability to the environment and fast growth and reproduction.Using non-woven bag as a breeding container for seedlings,the scale breeding and reproduction technique of F.tikoua container seedlings was summarized through the important links of seedling bed construction,seedling collection,soil configuration,container selection,cutting cultivation,field management,and disease and pest control.This technique can achieve differential,massive and sustainable efficient breeding and reproduction of F.tikoua seedlings in a short time.

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.

Transcriptome profiling of indole-3-butyric acid-induced adventitious root formation in softwood cuttings of walnut

Inducing adventitious root(AR)formation in mature walnut species(Juglans L.)is challenging.However,the AR formation of mature trees can be improved by rejuvenation.In rejuvenated cuttings,exogenous indole-3-butyric acid(IBA)is essential for AR formation,and the underlying mechanism is still not well understood.Therefore,we utilized transcriptome sequencing to investigate the mechanism of IBA-induced AR formation.Our results revealed that,in comparison to the control group,IBA treatment(9 mmol·L^(-1))significantly increased the endogenous indole-3-acetic acid(IAA)content,leading to an enhanced rooting rate.We performed RNA sequencing to identify differentially expressed genes(DEGs)between the IBA-treated and control(CK)groups at 1,2,3,and 5 days after cutting(DAC).The results showed that,compared to the control cuttings,there were 1539,889,785,and 984 up-regulated genes and 2791,2936,3017,and 1752 down-regulated genes,at 1,2,3,and 5 DAC,respectively.Analysis of RNA-seq data revealed that G-type ATP-binding cassette 36/37(ABCG36/37)and ATP-binding cassette subfamily D 1(ABCD1),associated with IBA transport,were down-regulated in the rejuvenation cuttings.In contrast,PIN-FORMED(PIN)and PINOID(PID),associated with auxin efflux,were up-regulated.We identified 49 auxin/indole-3-acetic acid(AUX/IAA)-encoding genes,including IAA1,IAA3,IAA5,IAA6,IAA8,IAA11,IAA12,IAA19,and IAA20,which were up-regulated at 1-5 DAC in the rejuvenated cuttings.This study highlights that the overexpression of JrWOX5/11 in poplar significantly enhance AR growth,as evidenced by increased root length,surface area,volume,and quantity.Moreover,the co-expression network analysis involving JrWOX11 and JrWOX5 in walnut cuttings elucidates complex genetic interactions,underscoring their pivotal role in the formation of AR.Our data supported the following molecular mechanism of IBA-induced adventitious root formation.Firstly,IBA is converted to free IAA in peroxisomes.Then,the highly concentrated IAA in the procambium and parenchyma cells induces WUSCHEL-related homeobox 11(WOX11)expression at two days.Finally,WOX11 acts redundantly to up-regulate WOX5,initiating the development of root primordia cells.

Biomass Allocation of Scirpus mariqueter Along an Elevational Gradient in a Salt Marsh of the Yangtse River Estuary

Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stress, the biomass allocations to different plant components and some related morphological parameters were examined along an elevational gradient within a salt marsh. Authors found that S. mariqueter performed best at medium elevation within the marsh, with relatively high density of shoot and individual ramet dry mass. Biomass allocation to corm was the highest at low elevations, and the least at high elevations, suggesting that a conservative strategy was adopted by the species to cope with the harsh physical conditions at the low elevation. The investment in rhizome decreased from low to high elevations, while the proportion of inflorescence mass increased, indicating that during the life history, the species shifts from predominant asexual reproduction to predominant sexual reproduction. This may be favourable for the species to colonize larger area, and to spread and persist at a meta_population level. Correlation analyses showed that sexual reproduction was inversely related to growth and asexual reproduction. However, it is difficult to determine the relationship between asexual reproduction and growth possibly because of the varied function of the corms of the species in different life history stages.

Molecular identification and culture observation on Acrochaete leptochaete (Chaetophoraceae, Chlorophyta) from China

Acrochaete leptochaete （Huber） Nielsen （Chaetophoraceae, Chlorophyta） was isolated from the macroalgae Chaetomorpha collected from intertidal pools in Rongcheng, Shandong, China. 18S rDNA combined with ITS regions were used to ascertain the morphological identification of the isolated material. Based on the unialgal culture, asexual reproduction and growth characteristics of A. leptochaete were investigated over wide ranges of temperature and irradiance. Results revealed that asexual reproduction of A. leptochaete could be realized by biflagellate zoospores. The zoospores germinated directly to give self- replicating generations. Zoospore germination was bipolar. A temperature range from 13-21 ℃ and a lower irradiance of 36 μmol/（m2.s） were most favorable for the growth ofA. leptochaete. Thallus organization, an important taxonomic criterion for the genus Acrochaete, was affected markedly by temperature and irradiance. Our results extend the knowledge about the species＇ general biology and its morphological plasticity. For classification and identification of a simple microphytic algae like A. leptochaete, which are traditionally placed in the class Chaetophoraceae, we propose that molecular tools associated with culture observations are applied.

Advances in Research of Cutting Breeding Technology of Xanthoceras sorbifolium Bunge

Cutting breeding is an important method of asexual reproduction of Xanthoceras sorbifolium Bunge.At present,it has been found that the factors influencing the cuttings of X.sorbifolium mainly include cutting material type,substrate type,cutting season,cutting material length and thickness,mother tree age,cutting material pretreatment method,hormone species concentration and soaking time.Besides,different regions,control conditions,and germplasm types have different cutting rooting rates.This paper introduced some of the problems in the cuttings of X.sorbifolium,and came up with some recommendations to provide a reference for the future research and technical promotion of X.sorbifolium cuttings.

ASF1 regulates asexual and sexual reproduction in Stemphylium eturmiunum by DJ-1 stimulation of the PI3K/AKT signaling pathway

Most fungi display a mixed mating system with both asexual and sexual reproduction.The timing of the two modes of reproduction must be carefully coordinated through signal perception and coordination in the cell along with chromatin modification.Here,we investigated coordination of reproductive output by investigating the function of the histone chaper-one anti-silencing factor 1(ASF1)in a fungal species amenable to characterization of both asexual and sexual reproduction.We used knockout approach to show that SeASF1 influenced asexual and sexual reproduction in Stemphylium eturmiunum.SeASF1-deleted strains failed to produce pseudothecia,but produce abnormal conidia and showed an irregular distribution of nuclei in mycelium.Transcriptome sequencing was then used to identify genes with altered expression in the SeASF1-deleted strains.The transcriptional expression of the identified SeDJ-1 was strongly regulated by SeASF1.The interaction of SeDJ-1 and SeASF1 was confirmed using Y2H,Co-IP,and pull-down.Due to some components of phosphatidylinositol 3-kinase/protein kinase B(PI3K/AKT)signaling pathway were known to interact with DJ-1 in mammals,we verified SePI3K,an element of PI3K/AKT signaling pathway in S.eturmiunum,was directly linked to SeDJ-1 and then these two proteins were defined as a coordinator of reproduction.However,knockout of SeDJ-1 or SePI3K altered the asexual and sexual repro-duction,but SePI3K recovered the asexual and sexual development of∆Sedj-1.The SeDJ-1-M6 segment of SeDJ-1 was essential for its interaction with SePI3K and played a critical role in restoring sexual reproduction in the∆Sepi3k,providing a deep understanding of the regulatory mechanism of SeDJ-1 in S.eturmiunum development.Summarily,SeASF1 is able to trigger SeDJ-1 and SeDJ-1can also activate SePI3K,which is orchestrally involved in asexual and sexual reproduction in S.eturmiunum.All these results reveal that SeASF1 manipulates asexual and sexual reproduction in S.eturmiunum by SeDJ-1 perception of PI3K/AKT signaling pathway.These data highlight the deep similarities in coordinating asexual and sexual processes in both fungi and eukaryotes in general.

Stable Adult Growth but Reduced Asexual Fecundity in Marginopora vertebralis,under Global Climate Change Scenarios

Large benthic foraminifera are an integral component of shallow-water tropical habitats and like many marine calcifiers,are susceptible to ocean acidification(OA)and ocean warming(OW).In particular,the prolific Symbiodiniaceae-bearing and high-magnesium calcite Marginopora vertebralis has a low threshold compared to several diatom-bearing and low-magnesium calcite species.In this multi-year mesocosm experiment,we tested three RPC 8.5 climate change scenarios(i)present day,(ii)the year 2050,and(iii)2100.To enable a realistic epiphytic association,these experiments were uniquely conducted using natural carbonate substrate,living calcifying alga,and seagrass.In contrast to previous studies,we detected no reduction in surface-area growth under future climate conditions compared with present day conditions.In terms of calcification,M.vertebralis’epiphytic association to primary producers(i.e.,calcifying algae and seagrasses)potentially ameliorates the effects of OA by buffering against declines in boundary layer pH during periods of photosynthesis(i.e.,CO_(2)removal).Importantly for population maintenance,we observed a strong reduction in asexual fecundity under the 2100 scenario.We propose the additional energy needed to maintain growth might be one reason for drastically reduced asexual reproduction.An alternative explanation could be that the 2℃temperature increase interfered with the environmental synchronization that triggered asexual multiple fission.We conclude that the low levels of reproduction will reduce populations in a high CO_(2)environment and reduce a valuable source of CaCO_(3) sediment production.