scholarly journals Comparative Seed Morphology of Tropical and Temperate Orchid Species with Different Growth Habits

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 161 ◽  
Author(s):  
Surya Diantina ◽  
Craig McGill ◽  
James Millner ◽  
Jayanthi Nadarajan ◽  
Hugh W. Pritchard ◽  
...  

Seed morphology underpins many critical biological and ecological processes, such as seed dormancy and germination, dispersal, and persistence. It is also a valuable taxonomic trait that can provide information about plant evolution and adaptations to different ecological niches. This study characterised and compared various seed morphological traits, i.e., seed and pod shape, seed colour and size, embryo size, and air volume for six orchid species; and explored whether taxonomy, biogeographical origin, or growth habit are important determinants of seed morphology. We investigated this on two tropical epiphytic orchid species from Indonesia (Dendrobium strebloceras and D. lineale), and four temperate species from New Zealand, terrestrial Gastrodia cunnninghamii, Pterostylis banksii and Thelymitra nervosa, and epiphytic D. cunninghamii. Our results show some similarities among related species in their pod shape and colour, and seed colouration. All the species studied have scobiform or fusiform seeds and prolate-spheroid embryos. Specifically, D. strebloceras, G. cunninghamii, and P. banksii have an elongated seed shape, while T. nervosa has truncated seeds. Interestingly, we observed high variability in the micro-morphological seed characteristics of these orchid species, unrelated to their taxonomy, biogeographical origin, or growth habit, suggesting different ecological adaptations possibly reflecting their modes of dispersal.

Phytotaxa ◽  
2018 ◽  
Vol 336 (3) ◽  
pp. 263
Author(s):  
İLKER GENÇ ◽  
ŞÜKRAN KÜLTÜR

A comprehensive study based on seed morphology of perennial Euphorbia (Euphorbiaceae) sect. Pithyusa species occurring in Turkey is presented. A total of 14 species were studied. Seed characteristics were examined using scanning electron microscopy (SEM) as well as dissecting light microscopy. Significant features are: seed size, seed shape, shape of caruncle and seed surface ornamentation. Three different seed surface types (smooth, pitted, and wrinkled) were observed. Four main seed shapes (ovoid, oblong, quadrangular, and globose), as well as seven types of seed coat ornamentation (reticulate-areolate, areolate, alveolate, falsifoveate, pusticulate, colliculate and smooth) were found. The number of testa cells per 100 µm2 and also its range, from 8–12 to 57–63, are given.


2009 ◽  
Vol 16 (1) ◽  
pp. 1-106 ◽  
Author(s):  
Piotr Szkudlarz

Variation in seed morphology in the genusEricaL. (Ericaceae)Seed morphology was studied in 136 species ofErica, including 123 from South Africa (Cape Floristic Region), 5 from tropical Africa, and 8 from Europe. Seed anatomy was studied in 13 selected species by light and scanning electron microscopy. Seed morphology of each species was described and documented by SEM micrographs. Ten major diagnostic features were selected, concerning seed shape, primary sculpture, and fine relief. On the basis of these features, the species were divided into 14 groups. Within them, 40 morphologically homogeneous subgroups were distinguished, which could possibly be used in future revisions of the genus. A key to species identification has been developed on the basis of seed characteristics. A very close similarity was observed between seeds of someEricaspecies from distant parts of the distribution range of this genus.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 470e-470 ◽  
Author(s):  
Neil O. Anderson ◽  
Peter D. Ascher

Advanced, two-species CBC individuals were used to create the first-ever, three-species hybrids between P. acutifolius, P. coccineus and P. vulgaris. M6 (2 species) × H15 (3 species) is the only three-species hybrid to date that segregates for diagnostic traits. Three generations of M6 (F2, F3, F4,) were used to create the series. Hybrid breakdown was most severe with M6 F2 × H15, producing 100% cripples that died before anthesis. In M6 F3 × H15 hybrids, segregation for stigma position, flower color, germination type, growth habit, leaf length/width ratios, and seed morphology commenced in the F1 hybrid generation. F, phenotypes, with P. coccineus flowers & seeds and P. acutifolius leaves & growth habit, had severe hybrid breakdown with weak self compatibility; purple seed coats, with or without black circundatus markings, and new flower colors were also produced. F1's with P. vulgaris growth habits were self-fertile and ceased segregating after the F2.


Author(s):  
F. Khoury ◽  
L. H. Bolz

The lateral growth habits and non-planar conformations of polyethylene crystals grown from dilute solutions (<0.1% wt./vol.) are known to vary depending on the crystallization temperature.1-3 With the notable exception of a study by Keith2, most previous studies have been limited to crystals grown at <95°C. The trend in the change of the lateral growth habit of the crystals with increasing crystallization temperature (other factors remaining equal, i.e. polymer mol. wt. and concentration, solvent) is illustrated in Fig.l. The lateral growth faces in the lozenge shaped type of crystal (Fig.la) which is formed at lower temperatures are {110}. Crystals formed at higher temperatures exhibit 'truncated' profiles (Figs. lb,c) and are bound laterally by (110) and (200} growth faces. In addition, the shape of the latter crystals is all the more truncated (Fig.lc), and hence all the more elongated parallel to the b-axis, the higher the crystallization temperature.


Author(s):  
Anita Roth-Nebelsick ◽  
Tatiana Miranda ◽  
Martin Ebner ◽  
Wilfried Konrad ◽  
Christopher Traiser

AbstractTrees are the fundamental element of forest ecosystems, made possible by their mechanical qualities and their highly sophisticated conductive tissues. The evolution of trees, and thereby the evolution of forests, were ecologically transformative and affected climate and biogeochemical cycles fundamentally. Trees also offer a substantial amount of ecological niches for other organisms, such as epiphytes, creating a vast amount of habitats. During land plant evolution, a variety of different tree constructions evolved and their constructional principles are a subject of ongoing research. Understanding the “natural construction” of trees benefits strongly from methods and approaches from physics and engineering. Plant water transport is a good example for the ongoing demand for interdisciplinary efforts to unravel form-function relationships on vastly differing scales. Identification of the unique mechanism of water long-distance transport requires a solid basis of interfacial physics and thermodynamics. Studying tree functions by using theoretical approaches is, however, not a one-sided affair: The complex interrelationships between traits, functionality, trade-offs and phylogeny inspire engineers, physicists and architects until today.


2021 ◽  
Author(s):  
Shulin Wang ◽  
Fujiang Hou

Abstract Aims Viable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), seed characteristics (size and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear. Methods We collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture. Results Forty-three plant species (mainly perennials) germinated from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small to medium-sized spherical seeds (seed size < 10 mg, shape index < 0.5) had the greatest germination potential. Conclusions Yaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and size directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.


2021 ◽  
Author(s):  
Basalapura Rangegowda Chandana ◽  
Sampangi Ramesh ◽  
Gonal Basanagouda ◽  
Rotti Kirankumar ◽  
Kyasampalli Venkatesh Reddy Ashwini

Abstract Growth habit is a plant architectural trait in grain legumes with no exception of horse gram. Determinacy and indeterminacy are the two types of growth habits reported in horse gram. Relative advantages of the two types of growth habit depend on the production systems to which cultivars are targeted. Dependable information on genetics of growth habit provide clues for adopting the most appropriate selection strategy to breed high yielding horse gram varieties with desired growth habit. Taking cues from the past studies, we hypothesize that growth habit in horse gram is controlled by two genes displaying inhibitory epistasis and indeterminacy is dominant over determinacy. To test this hypothesis, we monitored the inheritance of growth habit in F1, F2 and F3 generations derived from two crosses involving parents differing for growth habit. Contrary to our hypothesis, determinate growth habit of F1s of both the crosses suggested dominance of determinacy over indeterminacy. A good fit of observed segregation of F2 plants to that of the hypothesized segregation in the ratio of 13 determinate: 3 indeterminate plants, besides confirming dominance of determinacy, suggested classical digenic inhibitory epistatic control of growth habit. These results were further confirmed in F3 generation based on goodness of fit between observed numbers of plants segregating for determinacy and indeterminacy and those expected in the ratio of 49 determinate: 15 indeterminate plants. To the best of our knowledge, this is the first report on the inheritance of growth habit in horse gram.


Paleobiology ◽  
1986 ◽  
Vol 12 (3) ◽  
pp. 302-310 ◽  
Author(s):  
Michael A. Cichan

Specific conductance was calculated for secondary xylem in seven Carboniferous stem taxa utilizing an equation derived from the Hagen-Poiseuille relation. Arborescent and lianoid representatives of major pteridophytic (Calamitaceae, Lepidodenraceae, Sphenophyllaceae) and gymnospermous (Cordaitaceae, Medullosaceae) groups were examined. In the calamite Arthropitys communis and the seed plant Cordaites (Cordaixylon sp. and Mesoxylon sp.), conductance corresponded approximately to the low end of the range for both extant conifers and angiosperms. A substantially higher conductance was determined for the wood of Arthropitys deltoides, conforming to the high end of the range for conifers and the low-middle part of the range for angiosperms. The highest conductance values were found in Sphenophyllum plurifoliatum, Medullosa noei, and Paralycopodites brevifolius and corresponded to the middle-high portion of the range for vessel-containing angiosperms. This outcome is particularly significant in light of the fact that tracheary elements in the fossils are imperforate. The results indicate that conductance in secondary xylem of some of the most ancient, woody groups was comparable to that in extant plants and that highly effective conducting tissue developed relatively early in plant evolution. Moreover, it is suggested that the general relationship between wood anatomy, growth habit, and ecology demonstrated for living plants can also be extended back in time to include fossil plants.


2017 ◽  
Vol 35 (0) ◽  
Author(s):  
E. ALÇITEPE ◽  
S. ERKEN ◽  
F. GÜLBAG ◽  
M.E. ÖZZAMBAK

ABSTRACT Seeds of eleven perennial Gentiana collected from Turkey were analyzed using the SEM method. Other species excluding G. septemfida, G. boissieri, G. gelida were studied for the first time. They were identified and compared in terms of seed characteristics and surface ornamentations. Major characteristics including the outer periclinal walls of testa, sculpting of inner periclinal walls, seed shape, seed and testa cell, wing cell size, thickness of testa wall and seed shape have been proposed for Turkey Gentiana. They are divided into different types, such as no wing, chalazal wing, incomplete discoid wing, complete discoid wing according to the outer periclinal walls of testa. Considering primary sculpting of seeds, irregularly striate and shallowly reticulate type is observed. Anticlinal walls of G. olivieri, G. boissieri and G. gelida are curved, while others are straight. G. lutea has the largest mean seed (4.20 x 4.40 mm), while G. cruciata (0.67 x 0.60 mm) and G. olivieri have the smallest mean seeds (0.67 x 0.67 mm). Seed micromorphology can be used together with morphological character to form classifications in studied specimens for Gentiana genus.


2019 ◽  
Vol 26 (2) ◽  
pp. 315-324
Author(s):  
Soghra Ramzi ◽  
Shahryar Saedi-Mehrvarz

Seed morphology of 12 Iranian endemic and subendemic species of Veronica was studied using scanning electron microscope (SEM). Seven qualitative and quantitative characters were measured using SEM micrographs and stereomicroscopy. The seed shape of most species is ovate and plano-convex. The size of seeds ranges from 1.25 x 0.75 mm in V. khorassanica to 2.5 x 1.75 mm in V. viscosa Boiss. The ornamentation of seed coat is reticulate-verrucate in V. khorassanica, V. czerniakowskiana, V. mazanderanae and V. rubrifolia, reticulate-rugate in V. acrotheca, V. aucheri, V. viscosa and V. intercedens, rugose in V. microcarpa, V. chionantha and V. rechingeri, and reticulate-porate in V. gaubae. The testa cells are polygonal in ten species and irregular in two species. Micromorphological characters of seeds are useful in specific and subspecific delimitations of Iranian Veronica.


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