Regulation of Flowering Time by MicroRNAs

The shoot apical meristem (SAM) continuously produces lateral organs in plants.Based on the identity of the lateral organs,the life cycle of a plant can be divided into two phases:vegetative and reproductive.The SAM produces leaves during the vegetative phase,whereas it gives rise to flowers in the reproductive phase (reviewed in Poethig,2003).The floral transition,namely the switch from vegetative to reproductive growth,is controlled by diverse endogenous and exogenous cues such as age,hormones,photoperiod,and temperature (reviewed in B(a)urle and Dean,2006;Srikanth and Schmid,2011;Andres and Coupland,2012). The model annual Arabidopsis thaliana has been extensively used for the dissection of the molecular mechanism underlying the floral transition during the last two decades.The molecular and genetic analyses have revealed five flowering time pathways,including age,autonomous,gibberellins (GAs),photoperiod and vernalization (reviewed in Amasino and Michaels,2010).Growing lines of evidence indicate that there are extensive crosstalks,feedback or feed-forward loops between the components within these pathways,and that these multiple floral inductive cues are integrated into a set of floral promoting MADS-box genes including APETALA 1 (AP1),SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1),FRUITFULL (FUL) and LEAFY (LFY) (Amasino and Michaels,2010;Lee and Lee,2010;Srikanth and Schmid,2011).     

Control of flowering and inflorescence architecture in tomato by synergistic interactions between ALOG transcription factors

正Inflorescences are flower-bearing shoots that originate from pools of stem cells in shoot apical meristems (SAM).Inflorescence architecture is determined by a process of meristem maturation,during which stem cell fate switches from a vegetative to a reproductive growth program.A major factor in plant reproductive success in nature and yield in agriculture is the number of branches and flowers on inflorescences (Kobayashi and Weigel,2007;     

The identity of Dinochloa species and enumeration of Melocalamus(Poaceae:Bambusoideae) in ChinaOA

Three woody bamboo species collected in Hainan,China in 1940 have been described as Dinochloa based on vegetative specimens.However,the identity of these species has long been in doubt,largely because the vegetative phase in species of Dinochloa is morphologically similar to that in species of Melocalamus,a climbing or scrambling bamboo genus of the paleotropical woody bamboos(Poaceae:Bambusoideae)that consists of about 15 species and one variety.To determine the phylogenetic affinity of the thr...     

Existence of homologous sequences corresponding to cDNA of the ver gene in diverse higher plant species

INTRODUCT1ONIn the vast majority of higher plalls, a transitionfrom vegetative growth to reproductive developmentis strongly influenced by a set of environmental fac-tors, such as photoperiod, temperatu-re etc. Bothwinter trait and biennia1 plants require a period of1ow temperature fOr switching from vegetative to re-productive growth, and this process is known as ver-na1ization. Several physiological and genetic inves-tigations showed that the vrngenes control the ver-nalization traits of…     

Mating patterns and pollen dispersal in a Japanese larch(Larix kaempferi) clonal seed orchard: a case study

Pollination dynamics highly determines the genetic quality of seed orchard crops. However, there is less research about the effect of mating patterns on seed productivity of orchard crops. So far, clonal seed orchards have been producing genetically improved seedlings used for most Japanese larch(Larix kaempferi(Lamb.) Carr.) plantations in China. In the present study, a total of 17 highly variable simple sequence repeat(SSR) markers were used for genotyping a progeny trial population consisting of 647 open-pollinated progenies germinated from seeds which were collected from 63 maternal clones with 140 potential paternal clones in a Japanese larch clonal seed orchard in China. Paternity analysis was used in the present case study in order to evaluate the level of paternal gametic contribution, estimate pollen contamination and selfing rates, and investigate pollination patterns,pollen dispersal patterns and the impact of mating patterns on seed productivity of orchard crops. We observed 93.7% of the success rate of the parental assignment, unequal paternal gametic contribution(0–12.4%) with 6.3% of the progenies derived from pollen contamination or unsampled pollen donors, and absence of evidence for selfing. We also found that pollination rate highly depended on the distance between pollen donors and maternal parents, the majority of the identified crossing(65.7%)occurred between clones within a 150-m radius, and large variations in growth performance existed among the paternal halfsiblings. Progeny growth performance(diameter at breast(DBH) and height(HGT)) was measured at Age-20 in order to investigate the impact of mating patterns on timber production of orchard crops. As either the paternal or maternal, two clones(i.e., clones Z38 and Z62) were identified to have produced progenies with higher average stem volume breeding values than that of all of the progenies. Specifically, the genetic gains for volume were 3.53% for the two clones as paternal parents, and 8.26% as the maternal parents at Age-20. Thus, both elite clones were ideal candidates for the construction of next-generation clonal seed orchards due to their synchronous reproductive phenology with greater crossing rate and higher genetic gain. These results improved the pedigree information to provide solid evidence of mating patterns for future design and effective management of seed orchards and for the development of viable long-term breeding strategies for other coniferous species.     

Does pollinator dependence decrease along elevational gradients?OA

Plants have long been thought to be less dependent on pollinators for seed production at higher elevations due to adverse pollination environments.However,recent research has yet to consistently support the generality of this expectation.In this study,we asked whether pollinator dependence decreases along an elevational gradient and how it varies with various reproductive traits.To answer these questions,we quantified pollinator-plant associations and various reproductive traits for 112 flowerin...     

Genome size and sequence composition of moso bamboo: A comparative study

Moso bamboo (Phyllostachys pubescens) is one of the world's most important bamboo species. It has the largest area of all planted bamboo―over two-thirds of the total bamboo forest area―and the highest economic value in China. Moso bamboo is a tetraploid (4x=48) and a special member of the grasses family. Although several genomes have been sequenced or are being sequenced in the grasses family, we know little about the genome of the bambusoids (bamboos). In this study, the moso bamboo genome size was estimated to be about 2034 Mb by flow cytometry (FCM), using maize (cv. B73) and rice (cv. Nipponbare) as internal references. The rice genome has been sequenced and the maize genome is being sequenced. We found that the size of the moso bamboo genome was similar to that of maize but significantly larger than that of rice. To determine whether the bamboo genome had a high proportion of repeat elements, similar to that of the maize genome, approximately 1000 genome survey sequences (GSS) were generated. Sequence analysis showed that the proportion of repeat elements was 23.3% for the bamboo genome, which is significantly lower than that of the maize ge-nome (65.7%). The bamboo repeat elements were mainly Gypsy/DIRS1 and Ty1/Copia LTR retrotrans-posons (14.7%), with a few DNA transposons. However, more genomic sequences are needed to con-firm the above results due to several factors, such as the limitation of our GSS data. This study is the first to investigate sequence composition of the bamboo genome. Our results are valuable for future genome research of moso and other bamboos.     

New insights into gibberellin signaling in regulating flowering in Arabidopsis

In angiosperms,floral transition is a key developmental transition from the vegetative to reproductive growth,and requires precise regulation to maximize the reproductive success.A complex regulatory network governs this transition through integrating flowering pathways in response to multiple exogenous and endogenous cues.Phytohormones are essential for proper plant developmental regulation and have been extensively studied for their involvement in the floral transition.Among various phytohormones,gibberellin(GA)plays a major role in affecting flowering in the model plant Arabidopsis thaliana.The GA pathway interact with other flowering genetic pathways and phytohormone signaling pathways through either DELLA proteins or mediating GA homeostasis.In this review,we summarize the recent advances in understanding the mechanisms of DELLA-mediated GA pathway in flowering time control in Arabidopsis,and discuss its possible link with other phytohormone pathways during the floral transition.     

Are allometric model parameters of aboveground biomass for trees phylogenetically constrained?OA

Knowledge of which biological and functional traits have,or lack,phylogenetic signal in a particular group of organisms is important to understanding the formation and functioning of biological communities.Allometric biomass models reflecting tree growth characteristics are commonly used to predict forest biomass.However,few studies have examined whether model parameters are constrained by phylogeny.Here,we use a comprehensive database(including 276 tree species) compiled from 894 allometric bio...     

Characterization of a novel developmentally retarded mutant (drm1) associated with the autonomous flowering pathway in Arabidopsis

INTRODUCTIONThe transition from vegetative growth to reproductionis one of the most important developmental events in flow-ering plants since it is related to the competence and sur-vivability of a particular species living in a particularenvironment. The…     

Analyses of Sexual Reproductive Success in Transgenic and/or Mutant Plants

The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.     

Influence of visual targets and landmarks on honey bee foraging and waggle dancing

Animals use diverse sensory stimuli to navigate their environment and to recognize rewarding food sources.Honey bees use visual atributes of the targeted food source,such as its color,shape,size,direction and distance from the hive,and the landmarks around it to navigate during foraging.They transmit the location information of the food source to other bees if it is highly rewarding.To investigate the relative importance of these attributes,we trained bees to feeders in two different experiments.In the first experiment,we asked whether bees prefer to land on(a)a similar feeder at a different distance on the same heading or on(b)a visually distinct feeder located at the exact same location.We found that,within a short foraging range,bees relied heavily on the color and the shape of the food source and to a lesser extent on its distance from the hive.In the second experiment,we asked if moving the main landmark or the feeder(visual target)influenced recruitment dancing for the feeder.We found that foragers took longer to land and danced fewer circuits when the location of the food source,or a major landmark associated with it,changed.These results demonstrate that prominent visual atributes of food sources and landmarks are evidently more reliable than distance information and that foraging bees heavily utilize these visual cues at the later stages of their journey.     

CFD Validation of the Optimal Arrangement of the Propulsive Dorsal Fin of Gymnarchus niloticus

Gymnarchus niloticus, a typical freshwater fish, swims by undulations of a long-based dorsal fin aided by the two pectoral fins, while commonly it holds its body rigid and straight. The long flexible dorsal fin is the main propulsor of G niloticus; it has also considerable influence on the streamline profile. This paper proposes a CFD approach to validate that the natural arrangement of the propulsive dorsal fin is optimal. Using morphological data and a smoothness-keeping algorithm, the dorsal fin is ‘virtually＇ moved forward and backward with several displacements from the natural location. For each case, we reconstruct geometry, generate CFD grids, and calculate the pressure, viscous and total drag coefficients respectively. The results show that the pressure and total drag coefficients increase whether the dorsal fin is displaced forward or backward, and that greater displacement from its original position leads to greater pressure and total drag coefficients. This suggests that the natural position of the dorsal fin is significant for maintaining the fish＇s streamline profile and reducing drag.     

The onset in spring and the end in autumn of the thermal and vegetative growing season affect calving time and reproductive success in reindeer

A developing trophic mismatch between the peak of energy demands by reproducing animals and the peak of forage availability has caused many species'reproductive success to decrease.The match-mismatch hypothesis(MMH)is an appealing concept that can be used to assess such fitness consequences.However,concerns have been raised on applying the MMH on capital breeders such as reindeer because the reliance on maternal capita rather than dietary income may mitigate negative effects of changing phenologies.Using a long-term dataset of reindeer calving dates recorded since 1970 in a semidomesticated reindeer population in Finnish Lapland and proxies of plant phenology;we tested the main hypothesis that the time lag between calving date and the plant phenology in autumn when females store nutrient reserves to finance reproduction would lead to consequences on reproductive success,as the time lag with spring conditions would.As predicted,the reproductive success of females of the Kutuharju reindeer population was affected by both the onset of spring green-up and vegetative senescence in autumn as calves were born heavier and with a higher first-summer survival when the onset of the vegetation growth was earlier and the end of the thermal growing season the previous year was earlier as well.Our results demonstrated that longer plant growing seasons might be detrimental to reindeer's reproductive success if a later end is accompanied by a reduced abundance of mushrooms.     

Vegetative Proliferation and Secondary Proliferated Inflorescences Development in Grass Ischaemum barbatum Retz

We report the vegetative proliferation and new phenomenon of ＂secondary proliferated inflorescences＂ In the grass Ischaemum barbatum Retz, as determined by anatomical analysis of prepared sections of inflorescences. Leaves and shoots could be developed from the original splkelets of Inflorescences and plantlets developed when these shoots were transplanted to moist soil. ＂Secondary proliferated Inflorescences＂ is the first name here because some inflorescences that developed inadequacy are grown from the splkelet on the mother Inflorescence. Our investigation showed that this form of vegetative proliferation and secondary proliferated inflorescences development of L barbatum has arisen following late autumn fires of the previous year. It Is suggested that the sudden onset of a fire could lead to a hormone Imbalance or a chemical induction, which results in ephemeral vegetative proliferation even secondary proliferated inflorescences development in wild populations.     

Defective thymocyte apoptosis and accelerated autoimmune diseases in TRAIL-null mice

Immunological tolerance to self is essential for maintaining the integrity of the organ systems, and its breakdown may lead to the development of autoimmune diseases. Tolerance to self is maintained through several mechanisms, which include negative selection, functional inactivation (anergy) and suppression of autoreactive lymphocytes. However, only negative selection permanently removes autoreactive cells through apoptosis. While it has long been known that negative selection requires a T cell receptor (TCR) signal, it is unclear whether a death ligand signal is also involved. TRAIL, the tumor necrosis factor (TNF)-related apoptosis-inducing ligand, is a newly described member of the TNF family. Unlike other death ligands of     

Sexual reproductive structures of Latest Proterozoic multicellular rhodophytes (red algae) from South China

Carposporangium- and spermatangium-like reproductive structures associated with differentiated vegetative tissues have been observed in the multicellular rhodophyte fossils, which were well preserved in the 650-Ma-old phosphate rocks of Doushantuo Formation in Guizhou Province, South China. The fossils show details of cellular structures that are comparable to the female and male reproductive organs of some extant rhodophytes. The first fossil-histological evidence for sexuality of Precambrian non-vascular plants is provided.