Sepal Morphology Research Articles

Expression of cell-wall related genes is highly variable and correlates with sepal morphology

Expression of cell-wall related genes is highly variable and correlates with sepal morphology

Comparative Transcriptomic Analysis of the Development of Sepal Morphology in Tomato (Solanum Lycopersicum L.).

Sepal is an important component of the tomato flower and fruit that typically protects the flower in bud and functions as a support for petals and fruits. Moreover, sepal appearance influences the commercial property of tomato nowadays. However, the phenotype information and development mechanism of the natural variation of sepal morphology in the tomato is still largely unexplored. To study the developmental mechanism and to determine key genes related to downward sepal in the tomato, we compared the transcriptomes of sepals between downward sepal (dsp) mutation and the wild-type by RNA sequencing and found that the differentially expressed genes were dominantly related to cell expansion, auxin, gibberellins and cytokinin. dsp mutation affected cell size and auxin, and gibberellins and cytokinin contents in sepals. The results showed that cell enlargement or abnormal cell expansion in the adaxial part of sepals in dsp. As reported, auxin, gibberellins and cytokinin were important factors for cell expansion. Hence, dsp mutation regulated cell expansion to control sepal morphology, and auxin, gibberellins and cytokinin may mediate this process. One ARF gene and nine SAUR genes were dramatically upregulated in the sepal of the dsp mutant, whereas seven AUX/IAA genes were significantly downregulated in the sepal of dsp mutant. Further bioinformatic analyses implied that seven AUX/IAA genes might function as negative regulators, while one ARF gene and nine SAUR genes might serve as positive regulators of auxin signal transduction, thereby contributing to cell expansion in dsp sepal. Thus, our data suggest that 17 auxin-responsive genes are involved in downward sepal formation in the tomato. This study provides valuable information for dissecting the molecular mechanism of sepal morphology control in the tomato.

Sedum tarokoense (Crassulaceae), a new species from a limestone area in Taiwan.

BackgroundAn unknown Sedum was found from the limestone region in Taiwan. After a detailed comparison with other congeners in Taiwan and neighboring countries, we identified this plant as a new species.ResultsThis new taxon resembles S. nokoense Yamamoto, S. alfredii Hance, and S. uniflorum Hook. & Arn. subsp. oryzifolium (Makino) H. Ohba, but differs in leaf shape, sepal morphology, and seed testa micro-morphology. Ecologically, this new taxon occurs exclusively on limestone, while S. nokoense and S. alfredii grow in non-limestone areas and S. uniflorum subsp. oryzifolium is only found on sandy seashores.ConclusionsSedum tarokoense H.W. Lin & J.C. Wang is described as a new species. We provide a description, line drawing, and distribution map, as well as photograph, a key and a table to distinguish S. tarokoense from its related species.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-57) contains supplementary material, which is available to authorized users.

<p><strong><em>Dracula agnosia </em>(Orchidaceae: Pleurothallidinae), a long confused undescribed species</strong></p>

Dracula agnosia , long confused with D. olmosii , is formally described. The two species may be easily distinguished by their sepal morphology.

<p><strong>A new <em>Masdevallia </em>(Orchidaceae: Pleurothallidinae) from Colombia</strong></p>

Masdevallia unguentum is described and illustrated for the first time from material cultivated at Finca Dracula, Panama. The morphological similarities of the species are discussed, and the species is distinguished by fragrance and unique sepal morphology.

Taxonomy of Calyptridium parryi (Montiaceae)

Calyptridium parryi (Montiaceae, formerly Portulacaceae) putatively comprises four varieties: arizonicum, hesseae, nevadense, and parryi. We performed a detailed phenetic analysis of seed, fruit, and sepal morphology in order to assess the distinction and rank of these varieties. We treated the San Pedro Martir Mountains, Baja California populations of C. parryi as a separate taxonomic unit in these studies, given their great disjunct distribution. In addition, we included the very similar and largely sympatric C. monandrum in these analyses. Results from ANOVA and principal components analysis indicate that the six entities examined are, to various degrees, morphologically diagnosable. Calyptridium parryi varieties hesseae, nevadense, and parryi show some overlap in features, and we propose keeping these as varieties. Populations from the San Pedro Martir Mountains are distinct from other varieties of C. parryi, possibly warranting varietal status, but further studies with more samples are needed to confirm this. However, we conclude that C. parryi variety arizonicum is different enough in several features and geographic range to warrant species status, by a taxonomic/morphologic species concept. Calyptridium monandrum should be retained as a separate species.

Choices and Consequences of Oviposition by Hylemya (Delia) Sp. (Diptera: Anthomyiidae)

Hylema sp.5females oviposit on the undersides of sepals of developing buds of both Ipomopsis aggregata and Polemonium foliosissimum. Eggs deposited on the latter are significantly more likely to be fully protected by the sepal than are eggs deposited on the former. Unexposed eggs have a significantly greater likelihood of successfully developing to the larval stage than do exposed eggs. The difference in frequency of egg exposure on the two plant species can be attributed to differences in sepal morphology: I. aggregata sepals are significantly narrower than those of P. foliosissimum. The hypothesis that females preferentially oviposit on larger flowers was unconfirmed by a manipulative choice experiment. Plants differing in the size of their flowers were potted together and presented to Hylemya in arrays in the field. Flowers of the larger-flowered pair were no more likely to be oviposited on than flowers of the smaller-flowered pair. However, there were significant negative correlations between the corolla length and the percentage of flowers laid on per day at each of two sites. There was also a significant positive correlation between the corolla width and the percentage of flowers laid on at one site. Thus females appear to be using some measure of flower morphology, or a correlated trait, in making oviposition decisions. The degree to which Hylemya is making suboptimal choices between host plant species is discussed and requires further examination.

Stachys beckeana (Labiatae) in Albanien und Jugoslawien

Morphological and cytological investigations were carried out inStachys beckeanaDorfler & Hayek andS. recta L. subsp.sarajevensis sensuHayek. These two taxa have the same morphological characteristics (shape and indumentum of leaves; morphology of sepals, petals and fruits) and both have 2n = 2x = 34 chromosomes. They cannot be considered as different taxa;S. beckeanaDorfler & Hayek is the valid name (synonyms:S. recta L. subsp.sarajevensis sensuHayek,S. hayekiiMalý,S. recta L. subsp.hayekiiMalý).