Possible roles for ethylene and gibberellin in the phenotypic plasticity of an alpine population of Stellaria longipes

2006 ◽  
Vol 84 (7) ◽  
pp. 1101-1109 ◽  
Author(s):  
Leonid V. Kurepin ◽  
Lisa Mancell ◽  
David M. Reid ◽  
Richard P. Pharis ◽  
C.C. Chinnappa

Four phenotypically different genotypes from an alpine population of Stellaria longipes Goldie s.l. (Caryophyllaceae) were collected from neighbouring sites at the top of the Plateau Mountain in southeastern Alberta, Canada, to examine a possible hormonal basis for their differences in stem length, leaf size, and flowering characteristics. All four genotypes had a dwarf shoot phenotype, compared with the low-elevation ecotype. Among the four genotypes, PMI-D was the tallest and had the largest leaves and flowers as well as more flowers per plant. PMI-D also maintained the flowering state, upon repropagation, without low temperature, short-day vernalization. Under controlled long-day warm conditions, the PMI-D genotype had a higher rate of ethylene evolution, but contained levels of endogenous gibberellin A1 that were similar to the other three (smaller) alpine genotypes. PMI-D was more sensitive to exogenously applied ethylene and growth-active gibberellins than other alpine genotypes. In contrast, the other three genotypes were smaller, had fewer (and smaller) flowers, and exhibited low ethylene evolution and a reduced sensitivity to applied ethylene and growth-active gibberellins. Speculatively, this behaviour may indicate an adaptation within this unique population of “dwarf” phenotypes that involves enhanced sensitivity to endogenous ethylene and gibberellins.

2017 ◽  
Vol 51 ◽  
pp. 242-250
Author(s):  
M. V. Dulin

Tetralophozia setiformis is a widespread species occurring usually without organs of sexual and asexual reproduction. Gemmae of Tetralophozia setiformis were observed for the second time in Russia and Eurasia in the Northern Urals, Komi Republic. They form compact masses over upper leaves. The compact masses consist largely (70 %) of immature gemmae. Description of gemmae and gemmiparous shoots from the Northern Urals and their comparison with those from the other known localities, namely British Columbia (Canada) and the Murmansk Region (European Russia) were carried out. The gemmiparous plants of T. setiformis from the Northern Urals have approximately the same width as plants without gemmae but they are shorter. The leaves of gemmiparous plants from the Northern Urals are similar to leaves of gemmiparous plants from British Columbia. The leaf shape in upper part of the gemmiparous shoots varies from the typical to ± modified from gemmae production. These leaf shape transitions include reduction of leaf size and lobe number from 4 to 2–3, suppression of development and disappearance of characteristic teeth at the base of sinus. Gemmae size (17 × 22 μm) of plants from the Northern Urals is within variability recorded for plants from the Murmansk Region and British Columbia.


For identification of varieties, it is desirable to use genetically predetermined traits that are decisive for the varietal identification of the distinguishing characteristics of the varieties production and new genotypes for selection. The presence a complete evaluation of the selection samples a particular crop is the basis for the formation of informative databases characteristics the varieties of standards used in plant examination to determine the level of expression a characteristic particular genotype according to the code of their manifestation. For the 20 traits we used to identify, we identified 6 least volatile, highly trait-stable traits over the years of study to identify. These are: “coloring of the pubescence of the main stem”, “the size of the lateral leaf”, “the intensity of green leaf color”, “flower color”, “the intensity of brown bean color”, “basic color of the seed coat”. The other 14 traits are highly variable and unstable among varieties, but may be significant under certain conditions. According to the results of the research we have determined the conformity of the collection varieties by code graduation. In the study, we selected varieties with corresponding codes of attributes of the reference varieties the UPOV technique. On the basic of the color the pubescence of the main stem, 36% varieties are with grey stem pubescence. Among the standards: Apache, Alaric, Talon according to the grey color of the pubescence, we identified varieties Zolotysta, Ozzie, Diona. The 2947 564/84, Stepnaya-90, Knyazhna. The lateral leaf size is a sign that affects the increase in green mass of plants and subsequently on productivity. Graduation of the sign small size of leaf had varieties: Zuma, Ksenya; middle – Heinong 37, Yuh-30; large – 2947 564/84, Vinni, DSS 2504. The following is a sign of the intensity of leaf plate, which is divided by gradation into light, moderate and dark. Among our samples with a light degree of color, we can distinguish Diona, Sribna Ruta, and Zuma. For varieties with moderate gradation of color are selected: Perlyna, 93/99, Knyazhna. To the dark color of the leaf plate we attributed the varieties: Stepnaya-90, Ozzie. Among the varieties we studied of the basics of flower color 37% varieties are with a white flower, and 63% with a purple. According to the varieties of standards: Chandor, Cresir, Toreador to the white color of the flower we attributed varieties Knyazhna, Ozzie, Zolotysta. With the purple color of the flower we have selected varieties: 93/99, Zhemchuzhna, Heinong 37. On the basis of the intensity of brown color bean, which characterizes the generative organs of the plant, is divided into weak, moderate and strong, but the other identifiers there are gradations: sandy, gray, light brown, brown and dark brown, so we decided what would be better identify by color gradation. To the sandy color of the beans we attributed varieties Perlyna, Yuh-30; gray – Sribna Ruta; light brown – Kobza, Knyazhna; brown – Ksenya; dark brown – Zhemchuzhna, Vinni. Important features that identify the description of varieties include basic color of the seed coat, which affects the taste of the seeds. In particular, the seeds are divided by color into yellow – Kobza, Yuh-30; yellow-green – Vinni, Luch Nadezhdy; green – Heorhina; light brown – 2947 564/84, brown – DSS 2504; dark brown – 2974 YS-24 and black color – not detected. Following the results of the previous collection of soybean varieties from the morphological sings of vegetative, generative organs of plants, it was possible to identify varieties with stable manifestation of standard identifying sings of soybean. Collection varieties with one standard characteristics: Heinong 37, Luch Nadezhdy, DSS 2504, 2974 YS-24; two signs: Zolotysta, Diona, Stepnaya-90, Zuma, Ksenya, Heorhina, Sribna Ruta, Perlyna, 93/99, Zhemchuzhna; three signs: Ozzie, 2947 564/84, Yuh-30, Vinni, Knyazhna.


2002 ◽  
Vol 15 (2) ◽  
pp. 205 ◽  
Author(s):  
Christina Flann ◽  
Pauline Y. Ladiges ◽  
Neville G. Walsh

A study of morphological variation in Leptorhynchos squamatus (Labill.) Less. across its range in south-eastern Australia was undertaken to test the hypothesis that L. squamatus includes two taxa. Phenetic pattern analyses of both field-collected and herbarium specimens on the basis of morphology confirmed two major groups. Bract, cypsela, pappus bristle and leaf characters were particularly important in separating the two groups. The taxa are separated by altitude differences with one being a low-altitude plant found in many habitats and the other being a high-altitude taxon that is a major component of alpine meadows. Lowland plants have dark bract tips, fewer and wider pappus bristles than alpine plants, papillae on the cypselas and more linear leaves. A somewhat intermediate population from the Major Mitchell Plateau in the Grampians shows some alpine and some lowland characters but is included in the lowland taxon. Seeds from five populations (two alpine, two lowland and Major Mitchell) were germinated and plants grown for 18 weeks under four controlled sets of environmental conditions. The experiment showed that leaf size and some other characters are affected by environmental conditions, but that there are underlying genetic differences between the lowland and alpine forms. Leptorhynchos squamatus subsp. alpinus Flann is described here to accommodate the highland taxon.


1982 ◽  
Vol 62 (4) ◽  
pp. 969-977 ◽  
Author(s):  
PATRICIA S. HOLLOWAY ◽  
ROBERT M. VAN VELDHUIZEN ◽  
CECIL STUSHNOFF ◽  
DAVID K. WILDUNG

Vegetative growth of lingonberries was observed on plants growing in four unsterilized, native-Alaskan substrates: coarsely-ground Lemeta peat, Fairbanks silt loam soil, a mixture of peat and silt loam soil and washed Chena very fine sandy loam soil. Following three growing seasons, plants in the peat treatment showed the greatest increase in vegetative growth as revealed by the number of new stems produced, stem length and dry weight per plant. Leaf size did not differ among substrate treatments. The leaves on plants grown in the peat substrate remained green throughout the entire experiment. The leaves of plants in all other treatments showed varying degrees of chlorosis followed by reddening and necrosis. Differences in concentration of N, P, K, Mn, Fe, Zn and Al in whole-plant tissue samples were recorded. The results indicate lingonberries should be grown in a peat substrate for maximum growth and dry matter accumulation.


Author(s):  
Vladimír Gryc ◽  
Petr Horáček

The paper was aimed at the determination of variability of horizontal resin canal dimension in spruce wood in relation to the position in a spruce stem. Significant changes of dimensions in horizontal resin canal along the stem length and radius were found. On the basis obtained of results 3D models (for CW, OW, SWL and SWP zones) describing changes in resin canal dimensions in spruce in relation to the position in a stem were created. In the models, the resin canal dimension decreases with the height of a stem and on the other hand, with an increasing distance from the stem pith the dimension of resin canal increases. The importance of the paper consists in the enlargement of findings about the structure of spruce with compression wood.


2018 ◽  
Vol 31 (3) ◽  
pp. 779-790 ◽  
Author(s):  
PABLO FORLAN VARGAS ◽  
ERIC WATZKE ENGELKING ◽  
LUIS CARLOS FERREIRA DE ALMEIDA ◽  
ELIEL ALVES FERREIRA ◽  
HAMILTON CESAR DE OLIVERIA CHARLO

ABSTRACT The genetic variability within the crop species Ipomoea batatas is broad, hence, in order to support future breeding programs it is of the utmost importance that germplasm banks be created, conserved, and characterized. Therefore, the objective of this work was to rescue and evaluate the genetic divergence in sweet potato accessions collected in traditional communities of Vale do Ribeira Paulista. Sweet potato samples were collected from quilombos, indigenous villages, caiçaras communities, and small farms. The study was conducted between February 2013 and August 2014 in a randomized block design with three replications. Genetic material included 95 collected accessions and two commercial cultivars. Morphological characteristics of the accessions were evaluated and distances in the genetic distance matrix were estimated by means of multi-category variables, the data being subsequently clustered by the Tocher method. Analysis of the relative contribution of each characteristic and phenotypic correlation of descriptors was also performed. Results evidenced wide genetic diversity among the sweet potato accessions collected in Vale do Ribeira, which were not grouped according to the collection point. The descriptors that contributed more than 60% of genetic diversity included: leaf size, general leaf profile, immature leaf color, petiole pigmentation, predominant branch color, branch secondary color, stem length, cortical thickness, predominant periderm color, and periderm color intensity. Correlations between morphological descriptors was observed in 22.26% of the paired traits.


2015 ◽  
Vol 31 (3) ◽  
pp. 251-265 ◽  
Author(s):  
María Paula Balcázar-Vargas ◽  
Tinde R. van Andel ◽  
Paul Westers ◽  
Pieter A. Zuidema

Abstract:Secondary hemiepiphytes rely on other plants (hosts) to grow vertically. After germinating on the forest floor, their seedlings search a host to ascend. We recorded information on survival, growth, reproduction and vegetative propagation of three Heteropsis species, to evaluate what drives their vital rates. We measured 700 individuals of each study species between 2007 and 2009 in the southern Colombian Amazon. A gradual increase in stem length, leaf size, number of roots and plagiotropic branches was found with increasing height of Heteropsis individuals on their hosts. Survival of leafless non-climbing seedlings was very low (28% annually); increasing substantially (84–94%) once the seedling had ascended a host. The three Heteropsis species presented slow height growth rates (c. 2–8 cm y−1) with large variation, while a substantial percentage of the stems (31–62%) did not grow or dried out. Vegetative propagation in Heteropsis may act as a dispersion-propagation strategy to find a suitable host and reach the canopy again after falling. The slow growth rates suggest that Heteropsis individuals that have reached the canopy are rather old. Once plants have reached the tree crowns, their longevity is largely determined by the survival of the host tree.


1969 ◽  
Vol 17 (3) ◽  
pp. 375 ◽  
Author(s):  
LT Evans ◽  
RB Knox

Seedlings and older plants of 30 ecological races of Themeda australis were grown under controlled conditions to determine the effect of day length and vernalization on their flowering and on the incidence of apomixis. The races ranged in origin from latitude 6°S. in New Guinea to latitude 43°S, in Tasmania. One race from New Guinea and several from the Northern Territory behaved as strict short-day plants. The more southerly races, on the other hand, and several from north Queensland were long-day plants. In some, long days were required for both initiation and development of the inflorescence, in others apparently only for initiation. Some races required long days as seedlings, but not as older plants. Races from drier inland areas tended to be indifferent to day length in their flowering behaviour. At least four races from the colder areas responded to vernalization. Both the sexual and the aposporous reproductive pathways are described. Two races were wholly sexual in their breeding system and two appeared to be almost entirely aposporous, but most were versatile, displaying both sexual and aposporous reproductive behaviour. In seven races there was some evidence that day length influenced the reproductive pathway, short days causing increased apospory in all cases, regardless of the day length requirements for flowering.


1989 ◽  
Vol 29 (3) ◽  
pp. 445 ◽  
Author(s):  
KV Sharman ◽  
M Sedgley ◽  
D Aspinall

Cut flower production of 2 Australian native daisies, Helipterum roseum and Helichrysum bracteatum, was investigated in the glasshouse and outdoors at 4 planting times. Both species exhibited a long day response with floral initiation occurring in any photoperiod but with peak production following longer days. Peaks in bloom production occurred during the spring and summer regardless of planting time. Floral abnormalities were observed in Helipterum roseum in all environments and planting times with the exception of the outdoor winter planting. There was a tendency for inflorescence diameter of both species and stem length of Helipterum roseum to decline with time from anthesis of the apical inflorescence. Optimum production of top quality blooms of Helipterum roseum extended from October to January following planting between autumn and spring. Peak production of Helichrysum bracteatum between December and March can be expected following planting during winter and spring. It may be possible to extend these seasons by weekly planting from autumn to spring. In addition, the imposition of extended photoperiod or night break treatments following summer or autumn planting may fulfil the photoperiod requirements of the plants and stimulate increased production between March and November. It is proposed that both species be considered for the fresh cut flower market, with Helipterum roseum marketed as single stems and Helichrysum bracteatum as sprays.


2000 ◽  
Vol 36 (4) ◽  
pp. 509-516 ◽  
Author(s):  
I. C. ONWUEME ◽  
M. JOHNSTON

Since shading often occurs under normal growing conditions in various cropping systems (for example, intercropping, alley cropping), field experiments were carried out to determine the effects of shading on stomatal density, leaf size, leaf dry matter, and leaf lamina thickness in the major tropical root and tuber crops, tannia (Xanthosoma sagittifolium), sweet potato (Ipomoea batatas), yam (Dioscorea esculenta), cassava (Manihot esculenta), and taro (Colocasia esculenta). Shading decreased stomatal density in the lower epidermis of tannia, sweet potato, yam and cassava, and in the upper epidermis also in tannia and sweet potato; the upper epidermis of yam and cassava were devoid of stomata. In contrast to the other species, taro under shade had an increased stomatal density in both the upper and lower epidermis, a finding which was confirmed in subsequent pot experiments. This response of taro was postulated as a possible manifestation of greater shade adaptation by the species.For all the species, shading generally resulted in the production of larger (in terms of surface area) but thinner leaves, with a decreased dry matter concentration. For the two species (yam and cassava) that had stomata only on the lower epidermis, normal sun-grown plants had about twice as many stomata per unit area of lower epidermis than did corresponding plants of the other three species. The agronomic and physiological significance of the findings are discussed.


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