Near extinct Argyreia versicolor and rare Argyreia mekongensis are dependent on carpenter bee pollinators.

Argyreia versicolor and Argyreia mekongensis are extremely rare plant species. The former had not been seen for nearly 100 years until two individuals were found in Thailand in 2018, and only a handful of populations are known for the latter. The aims of this study were to examine the breeding systems of A. versicolor and A. mekongensis using pollination experiments and to determine their potential pollinators via floral observations. Our controlled pollination experiments uncovered the self-incompatibility of both species. Pollinator censuses indicated that females of two carpenter bee species, Xylocopa aestuans and Xylocopa latipes, were the predominant floral visitors for both Argyreia species. Our observations confirmed a harmonious match between the floral shape of both Argyreia species and the body sizes of these pollinators, ensuring effective pollen transfer and validating their role as putative pollinators. In line with the high frequency of pollinator visits observed, our controlled pollination experiments found no evidence of pollen limitation under field conditions. The findings of this study hold significance for the conservation of these endangered species, yet the situation is dire for A. versicolor, with one of the two individuals under study recently lost. Hence, it is crucial to intensify monitoring efforts for the species, aiming to identify additional individuals for potential inclusion in an ex-situ conservation program. Simultaneously, safeguarding the habitat of these plant species and their pollinators will be critical.

Compatibility systems and pollinator dependency in morning glory species (Convolvulaceae).

BACKGROUND: The Convolvulaceae is a large family containing species exhibiting a range of breeding systems and pollinated by diverse animal taxa. We studied the pollination ecology of 15 Convolvulaceae species, representing seven genera (Argyreia Lour., Camonea Raf., Evolvulus L., Hewittia Wight & Arn., Ipomoea L., Merremia Dennst. ex Endl., and Operculina Silva Manso), in northeastern Thailand, a family that is highly diverse yet understudied in the paleotropics. Specifically, we studied their compatibility systems and degrees of pollinator dependency using pollination experiments, examined pollinator composition and visitation rates using video observation, and determined if there is an association between pollinator visitation rates and degree of pollinator dependence. RESULTS: Our results showed that most species are self-compatible, but the degree of pollinator dependence varies. Six species were found to be highly dependent on pollinators, as two are self-incompatible and four are self-compatible but had reduced seed set when pollinators were excluded, possibly due to herkogamy. Seven species showed low dependence on pollinators and seed set remained high when pollinators were excluded. Pollinator dependence was inconclusive for two species as seed set was low in all pollination treatments. We also found an association between pollinator visitation rates and degree of pollinator dependence. Specifically, species exhibiting high pollinator dependence received frequent visits from pollinators, while species exhibiting low pollinator dependence either received frequent visits from pollinators (and received high amounts of xenogamous pollen) or infrequent visits from pollinators (and received significantly lower amounts of xenogamous pollen). Most of our study species were primarily visited by bees (e.g., Lasioglossum, Amegilla, Apis, and meliponines), with the exception of one night-blooming species that was visited primarily by crepuscular butterflies and hawkmoths. CONCLUSIONS: The cumulative findings of this study demonstrate how pollinator dependence is influenced by breeding system, and suggest that pollinator visitation is consistently high for species exhibiting high pollinator dependence but varies across species exhibiting low pollinator dependence. Our findings are also important for assessing the conservation risks of paleotropical Convolvulaceae.

Evolution and Classification of Musaceae Based on Male Floral Morphology.

Classification of the banana family (Musaceae) into three genera, Musa, Ensete and Musella, and infrageneric ranking are still ambiguous. Within the genus Musa, five formerly separated sections were recently merged into sections Musa and Callimusa based on seed morphology, molecular data and chromosome numbers. Nevertheless, other key morphological characters of the genera, sections, and species have not been clearly defined. This research aims to investigate male floral morphology, classify members of the banana family based on overall similarity of morphological traits using 59 banana accessions of 21 taxa and make inferences of the evolutionary relationships of 57 taxa based on ITS, trnL-F, rps16 and atpB-rbcL sequences from 67 Genbank and 10 newly collected banana accessions. Fifteen quantitative characters were examined using principal component analysis and canonical discriminant analysis and 22 qualitative characters were analyzed by the Unweighted Pair Group Method with an Arithmetic Mean (UPGMA). The results showed that fused tepal morphology, median inner tepal shape and length of style supported the three clades of Musa, Ensete and Musella, while shapes of median inner tepal and stigma classified the two Musa sections. In conclusion, a combination of morphological characters of male flowers and molecular phylogenetics well support the taxonomic arrangement within the banana family and the Musa genus and assist in selection of characters to construct an identification key of Musaceae.

How and Where Periglandula Fungus Interacts with Different Parts of Ipomoea asarifolia.

Periglandula is a fungal genus that is associated with plants in the family Convolvulaceae. They produce medicinally important constituents called ergot alkaloids, which are stored in their host plants. Previously, the fungi were reported to mainly interact with young leaves and seeds of Convolvulaceae species. However, knowledge about how ergot alkaloid-producing fungi interact with their host plants is still lacking. Therefore, we investigated the interaction of Periglandula fungus with different plant parts of Ipomoea asarifolia, using molecular, histochemical, anatomical and micromorphological techniques. Our findings confirm the presence of Periglandula ipomoeae on six out of the eight plant parts examined (young folded leaves, mature leaves, flower buds, mature flowers, young seeds and mature seeds). The fungus was mostly distributed along external plant surfaces, and particularly on areas that were relatively unexposed. Our results suggest that the density of fungal mycelium varies depending on glandular trichome density and the growth stage of the host plant. Detection of the fungus in the flowers of its host plant, for the first time, fills a missing link in understanding how vertical transmission of Periglandula species occurs.

Functional Ecology of External Secretory Structures in Rivea ornata (Roxb.) Choisy (Convolvulaceae).

Plants have evolved numerous secretory structures that fulfill diverse roles and shape their interactions with other organisms. Rivea ornata (Roxb.) Choisy (Convolvulaceae) is one species that possesses various external secretory organs hypothesized to be ecologically important. This study, therefore, aimed to investigate five secretory structures (nectary disc, petiolar nectaries, calycinal glands, staminal hairs, and foliar glands) using micromorphology, anatomy, histochemistry, and field observations of plant-animal interactions in order to assess the functional contributions of these structures. Results show that the nectary disc and petiolar nectaries are complex working units consisting of at least epidermis and ground tissue, while the other structures are glandular trichomes. Various groups of metabolites (lipids, phenolic compounds, polysaccharides, terpenoids, flavonoids, and alkaloids) were detected in all structures, while starch grains were only found in the nectary disc, petiolar nectaries, and their adjacent tissues. Integrating preliminary observation of animal visitors with micromorphological, anatomical, and histochemical results, two hypotheses are proposed: (I) nectary disc and staminal hairs are important for pollination as they potentially attract and reward floral visitors, and (II) petiolar nectaries, calycinal glands, and foliar glands contribute to plant defense. Specifically, petiolar nectaries and calycinal glands provide protection from herbivores via guard ants, while calycinal and foliar glands may use plant metabolites to help prevent tissue damage from dehydration and insolation.

Pollination and Floral Biology of a Rare Morning Glory Species Endemic to Thailand, Argyreia siamensis.

Argyreia siamensis is extremely rare, and very little is known about its reproduction. The species has colorful flowers that seem likely to attract pollinators, but population sizes are typically small (<30 individuals). To determine whether poor reproduction contributes to its rarity, we investigated its mating system and potential pollinators in two populations. We also examined the staminal trichomes and floral nectary to investigate their role in pollinator attraction. The mating system was assessed with a bagging experiment and pollinator visits were recorded with action cameras. Additionally, we tested the staminal trichomes and floral nectary for terpenes and flavonoids and examined floral nectary micromorphology via scanning electron microscope and compound light microscope. Our results reveal that A. siamensis is self-incompatible and dependent on pollinators; the western population was pollinated by bees (Meliponini and Amegilla), while the eastern population was mainly pollinated by skipper butterflies (Hesperiidae). Both staminal trichomes and the floral nectary appear to contribute to pollinator attraction through the presence of terpenes and flavonoids (in both secretory structures) and nectariferous tissue and nectarostomata (in the nectary). Our results indicate that A. siamensis has reliable and effective pollinators and that insufficient pollination is likely not a primary cause of its rarity.

Effects of crude oil on plant growth and leaf anatomical structures in a common coastal plant.

Phenotypic plasticity is one mechanism that allows organisms to adapt to changing environmental conditions, and is especially important for plants since they are generally immobile. Recent anthropogenic disturbances such as oil spills have expanded the types of stressors that plants must cope with, and more work is needed to understand the extent to which plants can adapt. This study examined the physiological and anatomical responses of Ipomoea pes-caprae to crude oil, and determined its plasticity in response to crude oil. Four concentrations of crude oil (1%, 2%, 3%, and 4% v/w) were applied to experimental plants and then compared with control plants over the next 120 days. Crude oil meaningfully impacted 4 out of 5 physiological characters (survival time, leaf length, leaf width, and chlorophyll content) and 4 out of 19 anatomical characters (leaf blade thickness, leaf spongy layer height, leaf adaxial cutin thickness, and leaf abaxial cutin thickness). These results demonstrate that I. pes-caprae exhibits low anatomical plasticity in response to crude oil, resulting in reduced survival and physiological performance. Our findings highlight the importance of understanding how anthropogenic actions affect relatively immobile plants, which are not always able to cope with such stressors.

A new species of Argyreia (Convolvulaceae) from Thailand.

Argyreia pseudosolanum Traiperm & Suddee, sp. nov. from the NE region of Thailand is described and illustrated. The new species is remarkable in having a very distinctive corolla shape similar to Solanum, and staminal filament bases glabrous or nearly glabrous with a few multicellular, uniseriate hairs at the attachment point on the corolla tube. Detailed descriptions, illustrations, a summary of the ecology and an IUCN conservation status are provided.

Continued Adaptation of C4 Photosynthesis After an Initial Burst of Changes in the Andropogoneae Grasses.

C$_{4}$ photosynthesis is a complex trait that sustains fast growth and high productivity in tropical and subtropical conditions and evolved repeatedly in flowering plants. One of the major C$_{4}$ lineages is Andropogoneae, a group of $\sim $1200 grass species that includes some of the world's most important crops and species dominating tropical and some temperate grasslands. Previous efforts to understand C$_{4}$ evolution in the group have compared a few model C$_{4}$ plants to distantly related C$_{3}$ species so that changes directly responsible for the transition to C$_{4}$ could not be distinguished from those that preceded or followed it. In this study, we analyze the genomes of 66 grass species, capturing the earliest diversification within Andropogoneae as well as their C$_{3}$ relatives. Phylogenomics combined with molecular dating and analyses of protein evolution show that many changes linked to the evolution of C$_{4}$ photosynthesis in Andropogoneae happened in the Early Miocene, between 21 and 18 Ma, after the split from its C$_{3}$ sister lineage, and before the diversification of the group. This initial burst of changes was followed by an extended period of modifications to leaf anatomy and biochemistry during the diversification of Andropogoneae, so that a single C$_{4}$ origin gave birth to a diversity of C$_{4}$ phenotypes during 18 million years of speciation events and migration across geographic and ecological spaces. Our comprehensive approach and broad sampling of the diversity in the group reveals that one key transition can lead to a plethora of phenotypes following sustained adaptation of the ancestral state. [Adaptive evolution; complex traits; herbarium genomics; Jansenelleae; leaf anatomy; Poaceae; phylogenomics.].

Physiological and anatomical responses of a common beach grass to crude oil pollution.

Oil pollution is one potential consequence of industry development, and oil contamination occurs in countries around the world. However, few studies have examined the detrimental effects of oil on plant anatomy. Therefore, the objectives of this study were (1) to determine the impacts of crude oil on the physiological and anatomical parameters of Ischaemum muticum L. (Poaceae) and (2) to examine its potential as a bioindicator of oil pollution. Experimental plants were treated with one of four concentrations of crude oil (1%, 2%, 3%, and 4% volume/weight) and compared to control plants (no oil applied). Four physiological and 23 anatomical parameters were measured 7, 15, 30, 45, and 60 days after treatment. Crude oil negatively affected both physiological traits (leaf width and chlorophyll content) and anatomical traits (midrib vascular bundle height, leaf cutin thickness, leaf vascular bundle width and height, abaxial and adaxial margin cutin thickness, adaxial stomata density, adaxial short cell width, and abaxial long cell width). In general, the affected traits were modified by even the lowest oil concentration tested (1%). We discuss the potential of I. muticum as a bioindicator of oil pollution, given its prevalence in coastal areas of the paleotropics and its sensitivity to oil contamination.

Effects of an oil spill on the leaf anatomical characteristics of a beach plant (Terminalia catappa L.).

This study investigated the short-term impacts of an oil spill on the leaf anatomical structures of Terminalia catappa L. from crude oil leakage in Rayong province, Thailand, in 2013. Approximately 3 weeks after the oil spill, leaves of T. catappa were collected along the coastline of Rayong from one affected site, five adjacent sites, and a control site. Slides of the leaf epidermis were prepared by the peeling method, while leaf and petiole transverse sections were prepared by paraffin embedding. Cell walls of adaxial epidermal cell on leaves in the affected site were straight instead of the jigsaw shape found in leaves from the adjacent and control sites. In addition, the stomatal index of the abaxial leaf surface was significantly lower in the affected site. Leaf and petiole transverse sections collected from the affected site showed increased cuticle thickness, epidermal cell diameter on both sides, and palisade mesophyll thickness; in contrast, vessel diameter and spongy mesophyll thickness were reduced. These significant changes in the leaf anatomy of T. catappa correspond with previous research and demonstrate the negative effects of oil spill pollution on plants. The anatomical changes of T. catappa in response to crude oil pollution are discussed as a possible indicator of pollution and may be used in monitoring crude oil pollution.

Identification among morphologically similar Argyreia (Convolvulaceae) based on leaf anatomy and phenetic analyses.

BACKGROUND: The genus Argyreia Lour. is one of the species-rich Asian genera in the family Convolvulaceae. Several species complexes were recognized in which taxon delimitation was imprecise, especially when examining herbarium materials without fully developed open flowers. The main goal of this study is to investigate and describe leaf anatomy for some morphologically similar Argyreia using epidermal peeling, leaf and petiole transverse sections, and scanning electron microscopy. Phenetic analyses including cluster analysis and principal component analysis were used to investigate the similarity of these morpho-types. RESULTS: Anatomical differences observed between the morpho-types include epidermal cell walls and the trichome types on the leaf epidermis. Additional differences in the leaf and petiole transverse sections include the epidermal cell shape of the adaxial leaf blade, the leaf margins, and the petiole transverse sectional outline. The phenogram from cluster analysis using the UPGMA method represented four groups with an R value of 0.87. Moreover, the important quantitative and qualitative leaf anatomical traits of the four groups were confirmed by the principal component analysis of the first two components. The results from phenetic analyses confirmed the anatomical differentiation between the morpho-types. CONCLUSIONS: Leaf anatomical features regarded as particularly informative for morpho-type differentiation can be used to supplement macro morphological identification.

Micro-morphological study of Evolvulus spp. (Convolvulaceae): the old world medicinal plants.

BACKGROUND: Several medicinal properties have been reported for plants in the genus Evolvulus, such as a brain tonic and antifungal from Evolvulus alsinoides, and a sedative and an anthelmintic from Evolvulus nummularius. Therefore, the correct identification of the source plants is critically important. The aim of this research was to investigate the micromorphology of two Evolvulus taxa used for herbal medicines compared with one worldwide ornamental species by using peeling, paraffin embedding, acetolysis, and SEM methods in order to support species identification. RESULTS: Our findings indicate that all taxa share several common features, such as a single layer of epidermis on both sides of leaf surfaces, sinuous anticlinal epidermal cell walls, anomocytic, paracytic or laterocytic stomata, and capitate glandular trichomes. Y-shaped hairs were found in two species but not in E. nummularius. Similarly, isobilateral mesophyll occurs in both E. alsinoides and Evolvulus glomeratus, but a dorsiventral mesophyll is present in E. nummularius. Stems consist of a single layer of epidermis, one to four chlorenchyma layers, one to seven layers of cortical cells and a bicollateral bundle with pith in the center. The seed coat epidermal cell shapes were irregular or polygonal with raised and undulated anticlinal boundaries, and folded or flattened to concave periclinal walls. Pollens of all taxa are monads, spheroidally shaped with 28-47 µm diameter, and 15-pantocolpate apertures type with microechinate ornamentation. CONCLUSIONS: An identification key to species is constructed based on leaf anatomy and seed coat characters. This data can be used in other subjects such as pharmaceutical botany, organic chemistry, taxonomy and horticulture, in terms of species identification.

Amaranthus species around Bangkok, Thailand and the release of allergenic proteins from their pollens.

BACKGROUND: Pollen of Amaranthus L., commonly known as careless weed or Phak-khom in Thai, has become one of the major causes of airway allergy in many countries including Thailand. Despite its recognized importance, there is no available information about which Amaranthus species are producing allergenic pollen more likely to affect Thai patients. Furthermore, only allergenic proteins released from pollen can cause allergy. OBJECTIVE: This study aimed to survey species of Amaranthus found in Bangkok and to investigate the impact of water on pollen damage and protein release from Amaranthus pollens. METHODS: Amaranthus inflorescences were sampled and identified using the identification key provided in "Flora of Thailand". Shed pollens were collected on day 1, 3 and 7 after shedding. Ten mg of pollens in distilled water including damaged pollens were counted under a light microscope. In addition, supernatant was analyzed for concentration of proteins released from pollens using Bradford's assay. Profiles of released proteins and IgE binding proteins were analyzed by SDS-PAGE and Western blot. RESULTS: Three species of Amaranthus-A. hybridus, A. spinosus, and A. viridis were identified. SDS-PAGE analysis revealed at least twelve protein bands with MW ranging from 10 to 80 kDa. Water caused more damage to pollens and higher amount of proteins were recovered from pollens 1 day after shedding than from 3- and 7-days old pollens. The results of Western blot showed IgE-bound proteins with MW ranging from 30 to 50 kDa. CONCLUSIONS: Water could damage pollens and time after shedding and significantly affected the amount of allergenic proteins released from pollen.