Heterostyly is a breeding system that promotes outbreeding through a combination of morphological and physiological floral traits. In Turnera these traits are governed by a single, hemizygous S-locus containing just three genes. We report that the S-locus gene, BAHD, is mutated and encodes a severely truncated protein in a self-compatible long homostyle species. Further, a self-compatible long homostyle mutant possesses a T. krapovickasii BAHD allele with a point mutation in a highly conserved domain of BAHD acyl transferases. Wild type and mutant TkBAHD alleles were expressed in Arabidopsis to assay for brassinosteroid (BR) inactivating activity. The wild type but not mutant allele caused dwarfism, consistent with the wild type possessing, but the mutant allele having lost, BR inactivating activity. To investigate whether BRs act directly in self-incompatibility, BRs were added to in vitro pollen cultures of the two mating types. A small morph specific stimulatory effect on pollen tube growth was found with 5 µM brassinolide, but no genotype specific inhibition was observed. These results suggest that BAHD acts pleiotropically to mediate pistil length and physiological mating type through BR inactivation, and that in regard to self-incompatibility, BR acts by differentially regulating gene expression in pistils, rather than directly on pollen.
Pseudochirita trifoliata, a new Gesneriaceae species from Pu Luong-Cuc Phuong limestone mountain range in northern Vietnam is described and illustrated here. This new taxon is the second species of the narrowly endemic genus Pseudochirita which is known from limestone areas in southern China and northern Vietnam. It is easily distinguished from P. guangxiensis by a set of differences on the leaves, bracts, calyx, external corolla indumentum, staminode number, pistil length, ovary indumentum, style indumentum, and capsule length. A detailed description, illustration, information on distribution, ecology, phenology, provisional conservation assessment using IUCN categories and criteria of the proposed new species, and comparison with its similar species, are also provided.
Heterostyly employs distinct hermaphroditic floral morphs to enforce outbreeding. Morphs differ structurally in stigma/anther positioning, promoting cross-pollination, and physiologically blocking self-fertilization. Heterostyly is controlled by a self-incompatibility (S)-locus of a small number of linked S-genes specific to short-styled morph genomes. Turnera possesses three S-genes, namely TsBAHD (controlling pistil characters), TsYUC6, and TsSPH1 (controlling stamen characters). Here, we compare pistil and stamen transcriptomes of floral morphs of T. subulata to investigate hypothesized S-gene function(s) and whether hormonal differences might contribute to physiological incompatibility. We then use network analyses to identify genetic networks underpinning heterostyly. We found a depletion of brassinosteroid-regulated genes in short styled (S)-morph pistils, consistent with hypothesized brassinosteroid-inactivating activity of TsBAHD. In S-morph anthers, auxin-regulated genes were enriched, consistent with hypothesized auxin biosynthesis activity of TsYUC6. Evidence was found for auxin elevation and brassinosteroid reduction in both pistils and stamens of S- relative to long styled (L)-morph flowers, consistent with reciprocal hormonal differences contributing to physiological incompatibility. Additional hormone pathways were also affected, however, suggesting S-gene activities intersect with a signaling hub. Interestingly, distinct S-genes controlling pistil length, from three species with independently evolved heterostyly, potentially intersect with phytochrome interacting factor (PIF) network hubs which mediate red/far-red light signaling. We propose that modification of the activities of PIF hubs by the S-locus could be a common theme in the evolution of heterostyly.
Despite relatively intensive work on the development of inflorescence primordia during grapevine growth in season one, some informational gaps are present in the flower and floral organ development in the season two. In addition, concurrents events of phenology and formation of flowers and floral parts has not been dealt with. With the aid of digital imaging, this research had three objectives; a) describe the developmental events that take place during and after bud break in the buds and in the individual flowers in terms of differentiation, b) match these events with phenological stages, and c) determine size-related growth of the floral organs. After careful dissecting and examination of the samples under microscopy, taken ever 5-10 days between March 20 and May 10 in 2016, the results indicated that highly esteemed works regarding the reproductive anatomy of grapevines needed some additional stages to fully describe events in the stamen and pistil primordia after the appearance of petal primordia. Five intermediate stages were added to the stages of “formation of flowers”. Differentiation of inflorescence and individual flowers occurred in the second season as the buds swelled in the spring. Stamens and pistil could be seen about 3 weeks later and completed their initial growth in another 3 weeks. Flower primordia was visible on April 1 and showed a more than 9-fold increase over the course of 5 to 6 weeks. flowers increased their width and their length more than 9- and 15-fold, respectively, between stage 8.1 (April 1) and 10.3 (May 10). At first, they were wider than they were longer, but at later stages they grew longitudinally. Reproductive organ primordia were visualized around the time of 2-4 leaves separated on the shoots. Signs of generative parts become apparent in late April. Anthers were the smallest in the flower. Filaments, on the other hand, elongated almost 7-fold in a period of 20 days. Gynoecium growth was the most impressive and total pistil length increased from 52.8 to 162 μm, ovary width from 40.4 to 99.8 μm, and stigma diameter from 9.96 to 44.9 μm in twenty days. By the time the pistil took its final shape, 6-8 leaves grew on the shoot during which inflorescence could also be seen.
Clausena smyrelliana Forster (2000: 716) was described from several gatherings collected from a few plants growing in littoral microphyll vineforests of South-East Queensland, Australia. Because of its rarity and of severe threats on its natural habitat, it has been listed as ‘Endangered’ under Queensland’s Nature Conservation Act 1992 (Atlas of Living Australia 2015). However, the combination of a long style (> 1/2 pistil length), lack of gynophore, straight staminal filaments, subcylindrical buds, and corymbiform inflorescence, excludes this species from Clausena Burman (1768: 87) and places it into Murraya J.Koenig (in Linné 1771: 554) (Molino 1994: 107)
The plum traditional fruit species in Hungary, several local cultivars was born in the different grower's districts. The author that investigated, that are morphological differences between an odds find self-fertile, self sterile (with functional stamens) and male sterile plum cultivars. For it thought about main questions of a scientific debate sown up and the study this way gave reactions totalize. There were in three fertile groups 8-8 type of feature plum cultivars in periods of 1992-2001, respectively 1993-1999. It was founded by author big odds found the troops on the basis of 9 traits between. Pistil length of self sterile cultivars very typical, such as sesquipedalian flower peduncle of the self-fertile plums and the hypoandry of male sterile cultivars. The relative stamen number and the pollen viability as well significant odds gave.
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Pistil Mating Type and Morphology Are Mediated by the Brassinosteroid Inactivating Activity of the S-Locus Gene BAHD in Heterostylous Turnera Species