Mixed Breeding System Research Articles

Pollination Syndrome, Florivory, and Breeding System of Satyrium nepalense var. ciliatum (Orchidaceae) in Central Yunnan, China.

Research on Satyrium nepalense var. ciliatum (Lindl.) Hook. f. has primarily focused on populations in Northwestern Yunnan, with limited studies on pollination syndromes and insect behavior. In addition, it is geographically limited in its breeding system studies. Here, pollination syndromes, florivory, and breeding systems of S. nepalense var. ciliatum from Liangwang Mountain (Central Yunnan, China) were investigated through field work, microscope, scanning electron microscope (SEM), and parafin section. It was revealed that the pollination syndrome was possessing out-crossing, such as bright color, a developed rostellum, nectar glands in the spur, and food hairs at the lip base. The color and nectar attracted flower visitors, and florivory was observed. Some flower visitors pollinated their companion species. Ants were identified as floral visitors for the first time in Satyrium, although substantial pollination was not observed. Ants might be potential pollinators. S. nepalense var. ciliatum possessed a mixed breeding system, including selfing, out-crossing, and apomixis, with apomixis being predominant in nature. It is suggested that the pollination syndrome, florivory, and pollination competition would contribute to its mixed breeding systems, particularly leading to the occurrence of apomixis.

Foraging activity and breeding system of Avicennia officinalis L. (Avicenniaceae) in Kerala, India

Field studies were carried out to assess the foraging activity and the breeding system of Avicennia officinalis L. in Chettuwa, Thrissur, India during the two flowering seasons of 2018–2019. A. officinalis, also known as the Indian mangrove is a common mangrove occupying the river banks of the Kerala coast of southern India. The plant blooms massively during the onset of the first summer showers. The flowering to fruiting period lasted from April to July. Bagging experiments revealed that A. officinalis preferred a mixed breeding system though they had a low fruit set recorded in self-pollination experiments. A total of 15 species of foraging insects belonging to three orders, Hymenoptera, Diptera, and Lepidoptera, were observed. The three most abundant insect foragers were Apis florea Fabr., Campsomeriella collaris Fabr., and Chrysomya megacephala Fabr. Among these, A. florea showed a significantly high visitation rate followed by C. collaris and then C. megacephala. C. collaris, however, had the highest and most significant handling time for Avicennia officinalis than A. florea. The peak foraging activity was recorded from 1000h to 1100h and from 1500h to 1700h. These findings emphasize the importance of insect flower visitors in the breeding of A. officinalis, highlighting the need to maintain the plant-pollinator relationships for the protection of mangrove ecosystems.

Sexual morph specialisation in a trioecious nematode balances opposing selective forces

The coexistence of different mating strategies, whereby a species can reproduce both by selfing and outcrossing, is an evolutionary enigma. Theory predicts two predominant stable mating states: outcrossing with strong inbreeding depression or selfing with weak inbreeding depression. As these two mating strategies are subject to opposing selective forces, mixed breeding systems are thought to be a rare transitory state yet can persist even after multiple speciation events. We hypothesise that if each mating strategy plays a distinctive role during some part of the species life history, opposing selective pressures could be balanced, permitting the stable co-existence of selfing and outcrossing sexual morphs. In this scenario, we would expect each morph to be specialised in their respective roles. Here we show, using behavioural, physiological and gene expression studies, that the selfing (hermaphrodite) and outcrossing (female) sexual morphs of the trioecious nematode Auanema freiburgensis have distinct adaptations optimised for their different roles during the life cycle. A. freiburgensis hermaphrodites are known to be produced under stressful conditions and are specialised for dispersal to new habitat patches. Here we show that they exhibit metabolic and intestinal changes enabling them to meet the cost of dispersal and reproduction. In contrast, A. freiburgensis females are produced in favourable conditions and facilitate rapid population growth. We found that females compensate for the lack of reproductive assurance by reallocating resources from intestinal development to mate-finding behaviour. The specialisation of each mating system for its role in the life cycle could balance opposing selective forces allowing the stable maintenance of both mating systems in A. freiburgensis.

First report on generalized pollination systems in Melastomataceae for the Andean páramos

AbstractMelastomataceae is a megadiverse family with records of transitions from specialized to generalized pollination systems for several species. These transitions are associated with the colonization of new, unpredictable and/or impoverished pollinator habitats or habitats where specialized pollinators are scarce (e.g., in highland environments). The bee species diversity is low in highlands. Therefore, autonomous breeding systems such as apomixis and self‐pollination emerge in these environments. In this paper, we studied the floral traits associated with the generalization of pollination systems and registered the floral visitors of two species in the Colombian Andes: Miconia cataractae and M. elaeoides. We investigated the breeding system of M. elaeoides. Both species presented small flowers, short anthers of medium pore size, and nectar‐producing stomata on the base of the anthers. Miconia cataractae produced an average of 1.62 μl nectar/flower, a sugar concentration of 6.78%, whereas M. elaeoides produced 0.09 μl nectar/flower, a sugar concentration of 6.13%. We recorded a wide diversity of pollinators for both species, mainly insects from the orders Hymenoptera and Diptera. Miconia elaeoides presented a mixed breeding system and was also capable of setting fruits by apomixis. We conclude that flower and anther morphology, combined with nectar production, thus represent convergent traits resulting in a generalist pollination system shared by M. cataractae and M. elaeoides. Here, we presented the first generalist pollination system recorded for Miconia (and the Melastomataceae) in the Andes, the first report for a species from the small‐pored section Amblyarrhena, and the first report for a species from the large‐pored section Cremanium in Colombia.

Recent advances in faba bean genetic and genomic tools for crop improvement.

Faba bean ( Vicia faba L.), a member of the Fabaceae family, is one of the important food legumes cultivated in cool temperate regions. It holds great importance for human consumption and livestock feed because of its high protein content, dietary fibre, and nutritional value. Major faba bean breeding challenges include its mixed breeding system, unknown wild progenitor, and genome size of ~13 Gb, which is the largest among diploid field crops. The key breeding objectives in faba bean include improved resistance to biotic and abiotic stress and enhanced seed quality traits. Regarding quality traits, major progress on reduction of vicine‐convicine and seed coat tannins, the main anti‐nutritional factors limiting faba bean seed usage, have been recently achieved through gene discovery. Genomic resources are relatively less advanced compared with other grain legume species, but significant improvements are underway due to a recent increase in research activities. A number of bi‐parental populations have been constructed and mapped for targeted traits in the last decade. Faba bean now benefits from saturated synteny‐based genetic maps, along with next‐generation sequencing and high‐throughput genotyping technologies that are paving the way for marker‐assisted selection. Developing a reference genome, and ultimately a pan‐genome, will provide a foundational resource for molecular breeding. In this review, we cover the recent development and deployment of genomic tools for faba bean breeding.

Flower visitors of Streptocarpus teitensis: implications for conservation of a critically endangered African violet species in Kenya.

BackgroundThe African violets are endangered plant species restricted mainly to the Eastern Arc Mountains biodiversity hotspots in Kenya and Tanzania. These plants grow well in shaded environments with high humidity. Given their restricted geographical range and published evidence of dependance on insect vectors to facilitate sexual reproduction, understanding their pollination biology is vital for their survival.MethodsWe conducted an empirical study using flower visitor observations, pan trapping and bagging experiments to establish the role of flower visitors in the fruit set of a locally endemic and critically endangered species of African violet in Taita Hills, Kenya, Streptocarpus teitensis.ResultsThe study found that fruit set is increased by 47.8% in S. teitensis when flowers are visited by insects. However, it is important to note the presence of putative autogamy suggesting S. teitensis could have a mixed breeding system involving self-pollination and cross-pollination since bagged flowers produced 26.9% fruit set.ConclusionsInsects appear to be essential flower visitors necessary for increased fruit set in S. teitensis. However, there is evidence of a mixed breeding system involving putative self-pollination and cross-pollination suggesting that S. teitensis is somewhat shielded from the negative effects of pollinator losses. Consequently, S. teitensis appears to be protected to a degree from the risks such as reproduction failure associated with pollinator losses by the presence of a safety net in putative self-pollination.

Profiling native and introduced perennial garden plants in Puerto Rican urban residential yards

AbstractWorldwide the number of non-native species escaping from cultivation into native habitats is steadily increasing with no signs of saturation. Species that eventually become invasive may generate unwanted social and ecological conditions especially in areas of conservation concern. This study built upon prior biodiversity work from 432 residential yards in the San Juan Metropolitan Area of Puerto Rico to evaluate the natural history and functional traits of native and non-native plant species in these green spaces. We reviewed the literature for a total of 361 plant species to extract information on their taxonomy, native distribution range, invasive status (casual, naturalized or invasive), life-form and ecological and biological species attributes. We then evaluated the relationship between their attributes and their probability of escaping cultivation and become invasive. Our results show that non-native species growing in yards are more likely to succeed in becoming invasive if they have vegetative growth, a mixed breeding system, and an unspecialized dispersal mode. We also found that native and non-native species occurring in residential yards share similar adaptive strategy scores. Most plant species that have already become invasive originated from Asia and America a fact that is likely tied to the US nursery trade. We used the combined results of this and prior studies to understand the factors facilitating plant invasion and to generate recommendations for the development of management strategies that may limit the spread of non-native ornamentals with the potential to escape cultivation and become invasive on this island.

Vector preference and heterogeneity in host sex ratio can affect pathogen spread in natural plant populations.

Vector-borne diseases threaten human and agricultural health and are a critical component of the ecology of plants and animals. While previous studies have shown that pathogen spread can be affected by vector preferences for host infection status, less attention has been paid to vector preference for host sex, despite abundant evidence of sex-specific variation in disease burden. We investigated vector preference for host infection status and sex in the sterilizing "anther-smut" pathogen (Microbotryum) of the alpine carnation, Dianthus pavonius. The pathogen is transferred among hosts by pollinators that visit infected flowers and become contaminated with spores produced by infected anthers. The host plant has a mixed breeding system with hermaphrodites and females. In experimental floral arrays, pollinators strongly preferred healthy hermaphrodites over both females and diseased plants, consistently across different guilds of pollinators and over multiple years. Using an agent-based model, we showed that pollinator preferences for sex can affect pathogen spread in populations with variable sex ratios, even if there is no preference for infection status. Our results demonstrate that vector preferences for host traits other than infection status can play a critical role in pathogen transmission dynamics when there is heterogeneity for those traits in the host population.

Geographic Patterns In Pollen Production In The Plant Ring SpeciesEuphorbia tithymaloidesIn The Caribbean

Abstract—We examine investment in male function in the context of geography and floral morphology in the plant ring speciesEuphorbia tithymaloides, which colonized the Caribbean from Mexico/Guatemala along two fronts that roughly correspond to the Greater and the Lesser Antilles and that meet in the vicinity of the Anegada Passage. Our results on investment in pollen relative to ovule production are consistent withE. tithymaloidesrelying on pollinators for reproduction across its range in the Caribbean. We document a geographic pattern of reduction in anther number and pollen:ovule ratios in populations ofE. tithymaloidestowards the Anegada Passage, which is consistent with a possible geographic transition towards a mixed breeding system where selfing has increased importance in this area where its two expansion fronts meet. The reduction in pollen production is correlated with inflorescence morphology, which converges to relatively shorter cyathia towards the Anegada Passage along both fronts. We discuss alternative scenarios and potential drivers of the patterns we document.

The unique inflorescence structure of Dorema aucheri (Apiaceae): An adaptation to the arid environment

Arid environments demand specific adaptations from plants in vegetative and reproductive systems. Self–compatibility, high pollen production and few well developed fruits are adapted to increase sexual reproductive success. Dorema aucheri is an arid–adapted, perennial monocarpic species endemic to southern Iran. It has a unique inflorescence structure. In this study, significance of inflorescence architecture for reproductive success was investigated in a wild population. The huge yellow inflorescences were frequently visited by manifold insects. The species is andromonoecious and spatially subdivided in a distal part with perfect flowers and a proximal part with male flowers. Flowers are protandrous and synchrononized in a duodichogamous manner which starts with the male, then female phase of the perfect flowers, followed by the male phase of the remaining flowers (7–10 days). Bagging assays confirmed that the plant is self–fertile. Sexual phases partly overlap allowing geitonogamy at some days and demanding obligate outcrossing at other days. The mixed breeding system and high degree of andromonoecy (77 ± 31%) coupled with an immense surplus of pollen grains (P/O =261,991:1), the long male flowering stage, attraction of flying pollinators by massive flowering and sexual asynchrony between neighboring plants are interpreted as adaptations to the arid environment increasing the rate of outcrossing.

Parâmetros genéticos e teste de paternidade em progênies de Euterpe oleracea produto da hibridação espontânea com Euterpe edulis em clima subtropical

O objetivo deste estudo foi avaliar o sistema de fecundação e a distribuição da variabilidade molecular entre e dentro de três grupos de progênies de polinização aberta de Euterpe oleracea, além de realizar um teste depaternidade para identificação dos genitores masculinos e promover a certificação genética das plântulasbífolioladas. Para tal, foram utilizados seis loci microssatélites em 306 amostras. Os grupos de progênies sãoresultado de um sistema misto de fecundação, com ausência de cruzamentos entre aparentados, sendoalógamos (tm e ts = 1,0), com correlação de autofecundação (rt) igual a 0,110. Foram constatados diferentesgraus de parentescos (rp), entre 15,5 a 26,1% de irmãos completos. A paternidade foi atribuída para 51% e 24% das amostras, com 80 e 95% de confiança respectivamente. Foram identificados 22 doadores de pólen e uma autofecundação, verificou-se que o morfotipo bífoliolado não é garantia de cruzamento intraespecifico, já que quatro progênies foram identificadas como híbridos interespecíficos. Foram detectados em média 7 a 12,3 alelos por locus e uma heterozigosidade média observada entre 0,382 a 0,898 e a esperada entre 0,354 a 0,693. O índice de fixação foi entre -0,053 a -0,319. A variação entre os grupos foi de 5%, sendo 95% dentro deles. Os resultados indicam boas perspectivas para realização de trabalhos futuros relacionados à predição de ganhos genéticos a partir da seleção entre e dentro dos grupos de progênies.

Reproductive characteristics that favor invasiveness inLeonotis nepetifolia(L.) R. Br.

AbstractReproductive systems are life attributes important in defining the demography and genetic constitution of invasive alien species populations. We describe the phenology, floral behavior and floral visitors in Mexican populations ofLeonotis nepetifoliaconsidered invasive in America, Asia and Oceania. The mating system was determined through pollination experiments and, with a morphological analysis of flowers (outcrossing index, OCI) and pollen/ovule ratio, the breeding system was evaluated. Germination of 1 and 2‐year‐old seeds was tested to assess the potential characteristics of germination.Leonotis nepetifoliawas reproductive for 7 months (June to December) and tended towards a specific season during autumn. Anthesis lasted 36 hr with protogyny and no hercogamy, with floral visitors of Apodiformes, Hymenoptera, Lepidoptera and Thysanoptera. Pollination experiments indicated a mixed mating system, whereas the OCI and the pollen/ovule ratio pointed towards a facultative xenogamous breeding system. Seed production was high (1,445 ± 132 seeds/plant); the seeds had potential longevity and were neutral photoblastic. One‐year‐old seeds germinated slightly later (= 2.6 ± 0.11 days) than 2‐year‐old seeds (= 1.9 ± 0.02 days), both synchronously (IS1yr= 0.88 ± 0.03 and IS2yr= 0.82 ± 0.02). Germination percentage for 1‐year‐old seeds was lower (55.33 ± 4.40%) than that of 2‐year‐old seeds (94.18 ± 0.59%), suggesting a potential longevity of the seeds in an optimal environment. Reproductive characteristics, such as wide reproductive period, mixed breeding system, copious seed production, seeds with potential longevity, and quick and synchronic germination in different light conditions, favor the invasive capacity ofLeonotis nepetifolia.

Environmental impact on the temporal production of chasmogamous and cleistogamous flowers in the mixed breeding system of Viola pubescens.

Viola pubescens is a perennial, mixed breeding herb that produces both chasmogamous and cleistogamous flowers at different times of the season. Once bud type is specified, it does not convert from one form to the other. While temporal production of the two flowers is known to be influenced by environmental factors, the specific environmental cues that signal emergence of each flower type have not been empirically studied. To investigate the environmental parameters driving seasonal development of chasmogamous versus cleistogamous flowers, a native V. pubescens population was examined during the spring and summer of 2016 and 2017. Measurements of light quantity, canopy cover, photoperiod, temperature, soil moisture, soil pH, and the number of chasmogamous and cleistogamous buds were collected on either a weekly or biweekly basis. Independent zero-inflated negative binomial (ZINB) regressions were used to model the odds of bud production (0 versus 1 bud) and bud counts (≥ 1 bud) as a function of the environmental variables. Results of the ZINB models highlight key differences between the environmental variables that influence chasmogamous versus cleistogamous bud development and counts. In addition to the ZINB regressions, individual logistic regressions were fit to the bud data. The logistic models support results of the ZINB models and, more crucially, identify specific environmental thresholds at which each bud type is probable. Collectively, this work offers novel insight into how environmental variables shape temporal development of chasmogamous and cleistogamous flowers, suggests distinct threshold values that may aid in selectively inducing each flower type, and provides insight into how climatic change may impact mixed breeding species.

Analysis of Six Transcription Factor Families Explores Transcript Divergence of Cleistogamous and Chasmogamous Flowers in Cleistogenes songorica.

Cleistogenes songorica is a cultivated turfgrass species that employs a mixed breeding system. To determine the morphological differences and molecular mechanisms of the chasmogamous (CH) and cleistogamous (CL) flowers of this species, we evaluated seed traits and analyzed six transcription factor (TF) families related to floral development. The seed traits from the CH and CL flowers were significantly different. In total, 12 CsAP2, 13 CsSPL, 9 CsGRF, 21 CsMYB, 15 CsMADS, and 1 CsLFY differentially expressed genes were identified from the transcriptome of the C. songorica flowers, which was further supported by evolutionary relationships and conserved motifs. All collinear gene pairs had a Ka/Ks ratio <1. Analysis of the promoters and miRNAs of the TFs revealed that the members of the six TF families may coregulate the divergence of CH and CL flowers during evolution. Two CsAP2, 8 CsSPL, 6 CsGRF, 3 CsMYB (targeted by miR172s, miR156s, miR396a/b and miR159a/b, respectively), and 15 CsMADS genes as well as 1 CsLFY gene may be involved in the development of CH and CL flowers. This study is the first to analyze the differences between CH and CL flowers at the TF-family level, which will help in the understanding of dimorphic turfgrasses.

Adaptive response of extreme epiphyte Tillandsia species (Bromeliaceae) is demonstrated by different sexual reproduction strategies in the Brazilian Chaco

AbstractSome epiphytes are adapted to extreme environments with the ability to survive drought as a result of their morphological (xeromorphism), anatomical (foliar trichomes or scales) and physiological features. In contrast to vegetative features, they may have diverse sexual reproductive strategies. Here we compared the flowering morphology, floral biology, breeding system and pollinators of Tillandsia duratii, T. loliacea and T. recurvifolia (Bromeliaceae) adapted to an extreme environment, the Brazilian Chaco. Tillandsia duratii and T. recurvifolia flower for 5–6 months, whereas T. loliaceae flowers for 11 months, mainly in the dry season, with low to high flowering overlap between them. Although these species generally show similar flowering morphology, they differ in size, colour, odour and/or floral functionality, suggesting non-sharing of pollinators among them. Bimodal pollination occurs in T. duratii (bees, moths other than hawkmoths) and T. recurvifolia (butterflies, hummingbirds); in T. loliacea, we recorded no floral visitors. Tillandsia recurvifolia is self-incompatible, has flowers which approach herkogamy and protandry, and depends on pollen vectors for fruit set. The other two species show reverse herkogamy, autonomous self-pollination and self-compatibility (mixed breeding system); therefore, pollinators are not required. The disparity in reproductive strategies among the three species suggests the possibility of selection for diverse modes of reproduction.

Transcriptomics Identifies Modules of Differentially Expressed Genes and Novel Cyclotides in Viola pubescens.

Viola is a large genus with worldwide distribution and many traits not currently exemplified in model plants including unique breeding systems and the production of cyclotides. Here we report de novo genome assembly and transcriptomic analyses of the non-model species Viola pubescens using short-read DNA sequencing data and RNA-Seq from eight diverse tissues. First, V. pubescens genome size was estimated through flow cytometry, resulting in an approximate haploid genome of 455 Mbp. Next, the draft V. pubescens genome was sequenced and assembled resulting in 264,035,065 read pairs and 161,038 contigs with an N50 length of 3,455 base pairs (bp). RNA-Seq data were then assembled into tissue-specific transcripts. Together, the DNA and transcript data generated 38,081 ab initio gene models which were functionally annotated based on homology to Arabidopsis thaliana genes and Pfam domains. Gene expression was visualized for each tissue via principal component analysis and hierarchical clustering, and gene co-expression analysis identified 20 modules of tissue-specific transcriptional networks. Some of these modules highlight genetic differences between chasmogamous and cleistogamous flowers and may provide insight into V. pubescens’ mixed breeding system. Orthologous clustering with the proteomes of A. thaliana and Populus trichocarpa revealed 8,531 sequences unique to V. pubescens, including 81 novel cyclotide precursor sequences. Cyclotides are plant peptides characterized by a stable, cyclic cystine knot motif, making them strong candidates for drug scaffolding and protein engineering. Analysis of the RNA-Seq data for these cyclotide transcripts revealed diverse expression patterns both between transcripts and tissues. The diversity of these cyclotides was also highlighted in a maximum likelihood protein cladogram containing V. pubescens cyclotides and published cyclotide sequences from other Violaceae and Rubiaceae species. Collectively, this work provides the most comprehensive sequence resource for Viola, offers valuable transcriptomic insight into V. pubescens, and will facilitate future functional genomics research in Viola and other diverse plant groups.

The role of phenotypic plasticity and pollination environment in the cleistogamous, mixed mating breeding system of Triodanis perfoliata.

The role of variable pollination environments in maintaining mixed mating systems is an active area of research. Dimorphic cleistogamy, in which a plant reproduces by both open, facultative outcrossing chasmogamous (CH) flowers and closed, cleistogamous (CL) flowers presents an excellent opportunity to study mixed mating. For example, plastic responses in allocation to an optimal floral type could serve as an adaptive strategy that maintains mixed mating under variable pollination environments. We tested for pollen limitation and plastic responses in allocation to different floral types under manipulated pollination conditions in the dimorphic cleistogamous, mixed mating annual, Triodanis perfoliata. Using a field population, we quantified pollen limitation, auto-fertility and plastic responses in the breeding system by measuring allocation to flower number and seed set of floral types. We found no evidence for pollen limitation for CH flowers, and CH flowers had low efficacy of autonomous selfing. Importantly, we found that T. perfoliata alters floral number following changes in pollination conditions, with pollen-supplemented plants having lower relative CH flower number than non-supplemented plants. Breeding system plasticity may allow for benefits from outcrossing through CH flowers, but also increased overall fitness through relatively cheap CL reproduction. After CH flowers receive pollen, subsequent production of CH flowers was reduced, which may be due to resource limitation. Our findings did not support a theoretical model predicting increased CH flowers with high pollination levels. These results increase our understanding of the role of pollination services and resource allocation in the maintenance of mixed mating systems, which also warrants further investigation.

High genetic diversity and differentiation of an extremely narrowly distributed and critically endangered decaploid rose (Rosa praelucens): implications for its conservation

Rosa praelucens is a critically endangered decaploid alpine rose with an extremely narrow geographic distribution in Northwestern Yunnan, China. We sampled almost all the extant individuals (527 individuals in 31 natural locations and 56 individuals preserved in three local living collections) to assess the genetic variation and to probe the genetic connectivity among the individuals and populations based on three cpDNA intergenic spacers and six fluorescent amplified fragment length polymorphism (AFLP) markers. The morphological traits from seven populations were also measured. R. praelucens exhibited high levels of morphological variation, genetic diversity, and differentiation. The extant individuals were clustered into eight groups in neighbor-net networks, and subsequent Bayesian analysis assigned them into three larger gene pools, both in accordance with their morphological traits, especially flower color. The living collections embraced two private cpDNA haplotypes and included three out of the species’ total eight AFLP genotypes. Rhizome clonal growth, decaploid, and mixed breeding system may largely contribute to high genetic diversity and differentiation in R. praelucens. We concluded that the endangered status of R. praelucens may mainly be due to habitat fragmentation and loss and inherent reproductive difficulties, rather than low genetic diversity. The populations contributing higher cpDNA genetic diversity, representing more AFLP genotypes, and encompassing private cpDNA haplotypes should be given conservation priority by creating plant-micro reserves. The living collections should also be targeted for further ex situ conservation, population recovery, and reintroduction of R. praelucens plants.

Reproductive ecology of Aegialitis rotundifolia Roxb., A crypto-viviparous mangrove plant species in Krishna mangrove forest, Andra Pradesh

Abstract Aegialitis rotundifolia is a hermaphroditic, self-compatible species with mixed breeding system. The floral characters indicate melittophilous pollination syndrome. Field studies indicate this species is melittophilous but anemophily also occurs due to its seaward occurrence where high winds usually prevail. Autogamy and allogamy are functional, and these modes indicate a “fail-safe” strategy for reproductive assurance when con-specifics do not occur nearby. Natural fruit set rate is 55-61%. The seed produces seedling within the fruit pericarp while it is still attached to the parent plant. Seedling or seed dispersal and establishment occurs through self-planting and stranding strategies.

Agarista revoluta (Ericaceae): A generalist plant with self-compatible and self-incompatible individuals

In the Neotropics, Ericaceae species occur mainly at high altitudes being adapted to pollination by bees or hummingbirds. These species are mainly self-compatible, a breeding commonly found at high altitudes. Agarista revoluta is an Ericaceae species that occurs in sandy coastal plains (restinga), a hot and dry lowland environment unusual for Ericaceae. This species has similar floral traits as other Ericaceae pollinated by bees. However, we do not know what reproductive strategies this plant use to deal with the extreme environment. We studied the floral biology, the breeding system and floral visitors of A. revoluta in the restinga. We found that the species is a generalist being visited by diurnal and nocturnal insects, and that the studied population presents a rare mixed breeding system, with both self-compatible and self-incompatible individuals. These results suggest that A. revoluta differs from other Ericaceae species from the Neotropics by presenting reproductive strategies (generalist pollination and mixed breeding system) that warrant their reproductive success in an unpredictable environment for pollination.