Search Results (8)

This study investigated dynamic pollen–stigma coordination to optimize interspecific hybridization in Dendrobium using D. ‘Burana Jade’ as the maternal parent and eight wild species as pollen donors. Stigma receptivity was comprehensively evaluated using a multi-indicator approach, including morphological characterization (crystal secretion and bulging papillae), histochemical benzidine-H₂O₂ staining, and enzymatic activity profiling (esterase and superoxide dismutase). Concurrently, pollen viability was assessed through TTC testing coupled with ultrastructural observations. Results identified a critical synchronization window: pollen viability peaked at 1–3 days post anthesis (DPA) or during the mid-anthesis phase, while stigmas exhibited maximal receptivity when secretory activity and antioxidant enzyme levels significantly increased. Using stage-specific pollination criteria, 8.4% of crosses (8/95) produced viable fruits, outperforming empirical methods by 2.8-fold. D. ‘Burana Jade’ showed cross-compatibility with four Dendrobium species (D. aphyllum, D. chrysotoxum, D. hercoglossum, D. thyrsiflorum), with D. thyrsiflorum hybrids achieving 54.81% embryogenesis and 22.38% germination. Three compatible combinations germinated successfully in vitro within 45–55 days on 1/4 MS medium supplemented with 20 g/L sucrose, 1 g/L tryptone, 180 mL/L coconut water, and 2.2 g/L Phytagel. Our findings establish that synchronizing pollen viability windows with stigma receptivity phases significantly enhances fruit set and hybrid seed viability, providing a phenology-driven strategy to overcome reproductive barriers in orchid breeding programs. This study provides key physiological criteria for Dendrobium hybridization, though their applicability to other orchids needs validation. Future multi-omics studies should explore cross-species compatibility mechanisms. Full article

Specklinia digitale is an epiphytic orchid endemic to Mexico. The destruction of its habitat has resulted in it being regarded as an endangered species, and, to our knowledge, no effort has been made to establish ex situ conservation programs. Here, we describe an in situ assessment of flower and fruit phenology and subsequent in vitro germination. We also established a successful protocol for asymbiotic in vitro germination and acclimatization using Murashige–Skoog (MS) medium at full (full-MS) and half (1/2 MS) strength as well as activated charcoal (AC). All-year flower and fruit production was confirmed. Nevertheless, we observed a low pollination occurrence. No significant difference in germination rate was found for the four treatments tested; however, after protocorm evaluation, full-MS plus AC emerged as the best treatment for S. digitale in vitro propagation. Germination of up to 90.53% was achieved in full-MS. The acclimatization survival was 95%. These observations and our effective germination protocol can be used in a comprehensive approach for conservation efforts of this species. Full article

The pollination characteristics and flowering phenology of Calanthe sieboldii were evaluated to elucidate its reproductive characteristics and breeding systems. Field observations and artificial pollination experiments were conducted to study the pollination biology in Xuancheng City, Anhui Province. Meanwhile, gas chromatography–mass spectrometry (GC-MS) was employed to analyze the species’ volatile organic compounds (VOCs). Key findings include the following: (1) the flowering period extends from mid-April to mid-May, with a population-level flowering duration of 29 days in 2017, individual plant flowering averaging 20.22 days, and single flower longevity ranging from 12 to 23 days (mean = 19.30 days); (2) the species exhibits deceptive nectar guides devoid of nectar, indicating food-deceptive pollination, with Bombus sp. identified as its primary pollinator; (3) the pollinial–ovule ratio and hybridization index suggest a high level of self-compatibility without autonomous self-pollination, with no significant difference in pollination success between self- and outcross populations; (4) GC-MS analysis identified methyl benzoate and acacia-related compounds as the primary VOCs of C. sieboldii. These findings provide valuable insights into the conservation and sustainable management of orchids, particularly C. sieboldii. Full article

The technology for reproducing orchids in vitro has had to evolve due to the demand for these plants and the high cost of the biotechnology used due to the agar, the gelling agent. Consequently, research has tended to search for natural substitutes for agar. Our work describes the use of pectin and mucilage hydrocolloids extracted from the local waste matter of two species of Opuntia (O. ficus-indica and O. robusta) to study as a gelling agent in vitro culture media for Cattleya sp. These hydrocolloids were obtained by alkaline hydrolysis. Subsequently, these were used in proportions of 0.8%, 0.6%, 0.4%, and 0.2% in combination with agar to study the gelation time, texture profile analysis (TPA), seed germination under light and dark conditions, and a phenological study, including orchid analyses of leaves and roots, root and leaf length, seedling height, and width of the best-designed treatment were studied. Our results demonstrate that the treatment composed of 0.4% O. ficus-indica pectin and 0.4% agar improves the germination time, plant growth, and the number of leaves and roots, resulting in a biostimulant formula for optimal in vitro growth of Cattleya sp. Full article

Numerous orchid species around the world have already been affected by the ongoing climate change, displaying phenological alterations and considerable changes to their distributions. The fly orchid (Ophrys insectifera L.) is a well-known and distinctive Ophrys species in Europe, with a broad distribution across the continent. This study explores the effects of climate change on the range of O. insectifera, using a species distribution models (SDMs) framework that encompasses different climatic models and scenarios for the near- and long-term future. The species’ environmentally suitable area is projected to shift northwards (as expected) but downhill (contrary to usual expectations) in the future. In addition, an overall range contraction is predicted under all investigated combinations of climatic models and scenarios. While this is moderate overall, it includes some regions of severe loss and other areas with major gains. Specifically, O. insectifera is projected to experience major area loss in its southern reaches (the Balkans, Italy and Spain), while it will expand its northern limits to North Europe, with the UK, Scandinavia, and the Baltic countries exhibiting the largest gains. Full article

The Pululahua Geobotanical Reserve is a protected natural area in the cloud mountain forest of Ecuador, so rich in orchid species despite being a volcanic area still under threat of volcanic activity. A comparative biodiversity study of orchids was carried out in two different sectors, Chaupisacha (CH) and La Reventazón (LR). Data were collected in 1 ha plots in each sector, in which all the orchids found were counted and two individuals of each species were retained. Immature individuals were conserved in a plant nursery until flowering. In CH, there were 922 individuals grouped into 24 genera and 55 species, while LR had 9196 individuals grouped into 26 genera and 46 species; only 14 species were found in both sectors. Different density and diversity indexes were calculated. The density (ind./100 m²) of CH was 0.96, while that of LR was 185.92. Simpson’s diversity (1 − λ) attained CH 0.903 ± 0.01 and LR 0.85 ± 0.01. The orchid diversity measured by the Shannon-Wiener diversity index (H′) was 1.29 for CH, differing significantly from that of LR (H′ 1.02). The medium equity (Jaccard’s J′) found was 0.61 in CH and 90.78 in LR. Limitations as regards the natural dispersion of orchids seemed to favor endemism. Some species, such as Dracula felix and Restrepia guttulate, are threatened with disappearance from the wild or are vulnerable, as is the case for Epidendrum polyanthogastrium. A lack of information on the phenology and anthropic impacts in the area limit the conservation of species, signifying that new protected figures and seed banks are necessary, especially in CH, owing to its high diversity of orchids. Full article

Mycorrhizae are an important energy source for orchids that may replace or supplement photosynthesis. Most mature orchids rely on mycorrhizae throughout their life cycles. However, little is known about temporal variation in root endophytic fungal diversity and their trophic functions throughout whole growth periods of the orchids. In this study, the community composition of root endophytic fungi and trophic relationships between root endophytic fungi and orchids were investigated in Bletilla striata and B. ochracea at different phenological stages using stable isotope natural abundance analysis combined with molecular identification analysis. We identified 467 OTUs assigned to root-associated fungal endophytes, which belonged to 25 orders in 10 phyla. Most of these OTUs were assigned to saprotroph (143 OTUs), pathotroph-saprotroph (63 OTUs) and pathotroph-saprotroph-symbiotroph (18 OTUs) using FunGuild database. Among these OTUs, about 54 OTUs could be considered as putative species of orchid mycorrhizal fungi (OMF). For both Bletilla species, significant temporal variation was observed in the diversity of root endophytic fungi. The florescence and emergence periods had higher fungal community richness of total species and endemic species than did other periods. Both Bletilla species were dominated by Agaricomycetes and Basidiomycota fungi throughout the whole year; however, their abundances varied between two Bletilla species and among phenological stages. Meanwhile, the ranges of ¹³C and ¹⁵N natural abundance were also highly dynamic across all growth stages of Bletilla species. Compared with the surrounding autotrophic plants, significant ¹³C enrichments (ε¹³C) were found across all phenological stages, while significant ¹⁵N enrichment in the florescence period and strong ¹⁵N depletion during the fruiting period were found for both Bletilla species. We can deduce that both Bletilla species obtained carbon from root endophytic fungi during the whole year. Additionally, the temporal varying tendency of root endophytic fungal diversity was consistent with ¹³C enrichments, which was also accord with the nutritional requirement of plant. Full article

The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0–95% of flowers, floral displays from 90–3300 mm² and capsules from 15–1300 mm³ per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59—95%), followed by sexually deceptive autumn or winter-flowering (18–39%), visual deception (0–48%) and sexually deceptive spring-flowering (13–16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4× greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate. Full article