Stem and leaf growth of alpine sun and prairie shade ecotypes of Stellaria longipes under different photoperiods: role of ethylene

2006 ◽  
Vol 84 (9) ◽  
pp. 1496-1502 ◽  
Author(s):  
Linda J. Walton ◽  
Leonid V. Kurepin ◽  
David M. Reid ◽  
C.C. Chinnappa
Keyword(s):  
Leaf Growth ◽  
Stem Elongation ◽  
Leaf Length ◽  
Leaf Expansion ◽  
Alpine Plants ◽  
Growth Responses ◽  
Stellaria Longipes ◽  
Length And Area ◽  
Radiation Conditions

Plant ecotypes of Stellaria longipes Goldie from competitive, shade-adapted prairie habitat and less competitive, nonshaded alpine habitat were subjected to shortened or extended photoperiod conditions. Increasing daylength was positively correlated to increased stem elongation in both ecotypes. Leaf length and area for shade (prairie) plants was significantly altered with increased photoperiods, whereas sun (alpine) plants exhibited minimal leaf expansion in response to increased photoperiod. Increased ethylene evolution in the alpine genotype during rapid stem elongation and extended photoperiods suggests that ethylene plays a growth regulatory role in this sun-adapted genotype. The prairie genotype evolved less ethylene during these same periods, indicating either a diminished requirement for elevated ethylene to effect elongation and leaf expansion responses or possibly increased ethylene sensitivity because of interactions with other hormones, such as gibberellin or auxin. The sun genotype consistently produced more ethylene than the shade genotype under all photoperiod treatments. We conclude that photoperiod alters stem elongation and leaf expansion responses; similar trends were observed for extended photoperiods as were observed for shaded conditions, specifically low light intensity (photosynthetically active radiation) conditions. Further, ethylene levels altered during these responses, especially in sun-adapted alpine plants, which suggests that ethylene is involved in these growth responses.

Effects of nitrogen supply on xylem cytokinin delivery, transpiration and leaf expansion of pea genotypes differing in xylem-cytokinin concentration

2004 ◽  
Vol 31 (9) ◽  
pp. 903 ◽  
Author(s):  
Ian C. Dodd ◽  
Chuong Ngo ◽  
Colin G. N. Turnbull ◽  
Christine A. Beveridge
Keyword(s):  
Sap Flow ◽  
Leaf Growth ◽  
Xylem Sap ◽  
Leaf Expansion ◽  
Growth Responses ◽  
Flow Rates ◽  
Plant Transpiration ◽  
Discernible Effect ◽  
Whole Plant ◽  
N Treatment

The rms2 and rms4 pea (Pisum sativum L.) branching mutants have higher and lower xylem-cytokinin concentration, respectively, relative to wild type (WT) plants. These genotypes were grown at two levels of nitrogen (N) supply for 18–20 d to determine whether or not xylem-cytokinin concentration (X-CK) or delivery altered the transpiration and leaf growth responses to N deprivation. Xylem sap was collected by pressurising de-topped root systems. As sap-flow rate increased, X-CK declined in WT and rms2, but did not change in rms4. When grown at 5.0 mm N, X-CKs of rms2 and rms4 were 36% higher and 6-fold lower, respectively, than WT at sap-flow rates equivalent to whole-plant transpiration. Photoperiod cytokinin (CK) delivery rates (the product of transpiration and X-CK) decreased more than 6-fold in rms4. Growth of plants at 0.5 mm N had negligible (< 10%) effects on transpiration rates expressed on a leaf area basis in WT and rms4, but decreased transpiration rates of rms2. The low-N treatment decreased leaf expansion by 20–25% and expanding leaflet N concentration by 15%. These changes were similar in all genotypes. At sap-flow rates equivalent to whole-plant transpiration, the low N treatment decreased X-CK in rms2 but had no discernible effect in WT and rms4. Since the low N treatment decreased transpiration of all genotypes, photoperiod CK delivery rates also decreased in all genotypes. The similar leaf growth response of all genotypes to N deprivation despite differences in both absolute and relative X-CKs and deliveries suggests that shoot N status is more important in regulating leaf expansion than xylem-supplied cytokinins. The decreased X-CK and transpiration rate of rms2 following N deprivation suggests that changes in xylem-supplied CKs may modify water use.

Light regulation of endogenous salicylic acid levels in hypocotyls of Helianthus annuus seedlings

Botany ◽  
2010 ◽  
Vol 88 (7) ◽  
pp. 668-674 ◽  
Author(s):  
Leonid V. Kurepin ◽  
Linda J. Walton ◽  
David M. Reid ◽  
C. C. Chinnappa
Keyword(s):  
Salicylic Acid ◽  
Helianthus Annuus ◽  
Leaf Growth ◽  
Stem Elongation ◽  
Light Regulation ◽  
Shade Avoidance ◽  
Light Conditions ◽  
Direct Role ◽  
Positive Effects

Plants growing in canopy shade typically exhibit increased stem elongation and reduced leaf growth. This is as a result of direct interactions between plant photoreceptors sensing the change (reduction) in the ratio of red to far-red (R/FR) light and photosynthetically active radiation (PAR) and plant hormones, and regulating these morphological traits. The effect of the varying light conditions found in shade on endogenous salicylic acid (SA) content was tested, and the possible role of SA in shade avoidance by sunflower ( Helianthus annuus L.) hypocotyls was examined. A logarithmic increase in PAR irradiance levels increased endogenous SA levels roughly 10-fold. Separation of individual light wavelengths (R, FR, and blue) constituting the PAR irradiance of sunlight, established that only FR light had significant and positive effects on endogenous SA levels. Further, a low R/FR ratio significantly increased the endogenous SA content in hypocotyls compared with normal and high R/FR ratios. Uncoupling the effect of R/FR ratio and PAR irradiance on endogenous SA content demonstrated that PAR irradiance is a much stronger signal than FR light-enrichment. Thus, while a low R/FR ratio increases the SA content in sunflower hypocotyls, low PAR, the other component of canopy shade, decreases the SA content much more effectively than low R/FR ratio increases it. Therefore, it appears that SA probably has no direct role in shade avoidance effects.

The role of endogenous ethylene in the expansion of Helianthus annuus leaves

1997 ◽  
Vol 75 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Siew Hwee Lee ◽  
David M. Reid
Keyword(s):  
Carboxylic Acid ◽  
Helianthus Annuus ◽  
Acid Treatment ◽  
Leaf Growth ◽  
Leaf Expansion ◽  
Silver Thiosulphate ◽  
Ethylene Concentration ◽  
Endogenous Ethylene ◽  
Ethylene Action

The possible role of ethylene in leaf expansion of the primary leaves of sunflower plants (Helianthus annuus) was studied. Our lowest application of ethephon promoted expansion of primary leaves. Higher concentrations of ethephon, and a range of concentrations of 1-aminocyclopropane-1-carboxylic acid, increased endogenous ethylene concentration and caused a reduction in the area of the primary leaves. The inhibition in leaf expansion induced by ethephon and 1-aminocyclopropane-1-carboxylic acid was reversed by pretreating the plants with an inhibitor of ethylene action, namely silver thiosulphate. Treating leaves with lower concentrations of aminoefhoxyvinylglycine reduced ethylene production and stimulated leaf expansion. This effect of aminoethoxyvinylglycine could be nullified by pretreating the plants with 1-aminocyclopropane-1-carboxylic acid. Treatment with silver thiosulphate enhanced leaf expansion. This indicates that endogenous ethylene normally plays a significant role in leaf expansion. Flooded and gravistimulated plants produced more ethylene and had smaller leaves. This could suggest that the increased ethylene is the main cause of the slowed leaf growth, however, only in some cases were we able to partially reverse the effect of flooding with silver thiosulphate. This indicates that there are probably many factors, in addition to increased ethylene, that inhibit leaf expansion in flooded and gravistimulated plants. Key words: ethylene, leaf expansion.

Photosynthesis of newly matured leaves during the ontogeny of barley grown at different nutrient levels

1975 ◽  
Vol 53 (21) ◽  
pp. 2389-2398 ◽  
Author(s):  
P. Ma ◽  
L. A. Hunt
Keyword(s):  
Nutrient Solution ◽  
Stem Elongation ◽  
Specific Weight ◽  
Leaf Length ◽  
Day Length ◽  
Silica Sand ◽  
Hordeum Vulgare L ◽  
Before And After ◽  
Length And Area ◽  
Hoagland Nutrient Solution

Various growth characteristics were measured throughout ontogeny for barley plants (Hordeum vulgare L. cv. Brant) grown in silica sand and irrigated daily with one-eighth (0.125 N), one-fourth (0.25 N), and one-half (0.5 N) dilutions of a modified Hoagland nutrient solution, at day–night temperatures of 25–20 °C, an irradiance of 53 nE cm−2 s−1 (400–700 nm), and a day length of 15.5 h.The net CO2 exchange rate (NCE) of newly matured leaf laminae did not differ between measurements made at the same irradiance before and after noon. By contrast, NCE was greater at all stages except stem elongation for plants supplied with 0.5 N nutrient solution than for those receiving 0.25 N and 0.125 N solutions. The nutrient effect was apparent even for the first leaf produced. A distinct ontogenetic pattern of change in leaf NCE was apparent under all nutrient treatments: NCE increased from leaf 1 to leaf 3, remained constant between leaf 3 and leaf 5, declined between leaf 6 and leaf 9, and then increased markedly from leaf 10 onwards. The changes in leaf NCE appeared to be associated with major events in ontogeny.Rate of leaf appearance was constant through ontogeny and was not affected by nutrient supply. Final leaf number was greater for the 0.5 N nutrient solution. Leaf length, width, area, and specific weight increased throughout the early stages of ontogeny, and decreased later. The decrease in leaf length and area was less for plants supplied with more nutrients.

Calcium inhibition halts developmental programmed cell death in the lace plant, Aponogeton madagascariensis?

Botany ◽  
2010 ◽  
Vol 88 (2) ◽  
pp. 206-210 ◽  
Author(s):  
Anna Elliott ◽  
Arunika H.L.A.N. Gunawardena
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Leaf Growth ◽  
Indirect Evidence ◽  
Ruthenium Red ◽  
Leaf Length ◽  
Leaf Morphogenesis ◽  
Whole Plants

This study examined the effect of the calcium channel blocker ruthenium red (RR) on developmental programmed cell death (PCD) and perforation formation in leaves of the aquatic lace plant ( Aponogeton madagascariensis (Mirbel) H. Bruggen). Plant immersion experiments were conducted using various concentrations (0, 10, 20, 30, and 40 µmol·L–1) of RR applied to whole plants over a 3 to 4 week period. The ratio of number of leaf perforations per centimetre of leaf length along with leaf length were used to assess treatment effect. While the ratio of number of perforations per centimetre of leaf length was significantly reduced with RR treatment, leaf length was not, overall, significantly affected by RR. Therefore, it was concluded that RR was able to inhibit calcium movement and halt PCD, thus reducing perforation formation without having detrimental effects on leaf growth. The present research provides indirect evidence of the possible role of calcium in developmental PCD in vivo during leaf morphogenesis in the lace plant. Furthermore, it suggests the usefulness of the lace plant as a model system for pharmacological studies involving developmental PCD.

scholarly journals The Receptor Kinase BRI1 promotes cell proliferation in Arabidopsis by phosphorylation- mediated inhibition of the growth repressing peptidase DA1

2020 ◽  
Author(s):  
Hui Dong ◽  
Caroline Smith ◽  
Rachel Prior ◽  
Ross Carter ◽  
Jack Dumenil ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Regulatory Network ◽  
Leaf Growth ◽  
Proliferative Potential ◽  
Peptidase Activity ◽  
Receptor Kinase ◽  
Growth Responses ◽  
Regulatory Cascades ◽  
Cell Growth And Differentiation

SummaryBrassinosteroids (BR) have centrally important functions in plant growth by promoting cell proliferation and cell expansion through phosphorylation-mediated regulatory cascades that are initiated by perception of BR by receptor-like kinases of the BRI1 family. These BR-mediated growth responses have been explained by transcriptional controls mediated by phosphorylation of BES1/BZR1 transcription factors. Here we link BRI1-mediated phosphorylation to another growth regulatory network that directly mediates protein stability. BRI1 and its co-receptor BAK1 phosphorylate and inhibit the activities of the growth repressor DA1 by promoting the formation of high molecular weight complexes. Phospho-mimic forms of DA1 are less active while phospho-dead mutants have increased growth-repressive activity, while their regulatory monoubiquitylation is unaffected. BR inhibition of DA1 activity maintains higher levels of DA1 substrates such as UBP15 that sustain the potential for cell proliferation during leaf growth. Reduced BR levels lead to activation of DA1 peptidase activity and a transition from cell proliferation to cell growth and differentiation. This dual monoubiquitylation-phosphorylation regulation supports the key role of BR levels in maintaining the proliferative potential of cells during organ growth.

Role of Root Derived ABA in Regulating Early Leaf Growth Responses to Water Deficits

1997 ◽  
pp. 147-154 ◽  
Author(s):  
Peter Neumann ◽  
Ofer Chazen ◽  
Lev Bogoslavsky ◽  
Wolfram Hartung
Keyword(s):  
Leaf Growth ◽  
Growth Responses ◽  
Water Deficits

scholarly journals Leaf growth under temperature and light control

2009 ◽  
Vol 55 (No. 12) ◽  
pp. 551-557 ◽  
Author(s):  
J. Repková ◽  
M. Brestič ◽  
K. Olšovská
Keyword(s):  
Leaf Growth ◽  
Leaf Length ◽  
Leaf Expansion ◽  
Main Stem ◽  
Leaf Position ◽  
Temperature Sum ◽  
Air Temperatures ◽  
Strong Relation ◽  
Accumulated Temperature ◽  
Leaf Appearance

Dynamics of crop growth and photosynthesis are two main processes that are of major importance for adaptation of plants to their environment. Two experiments were carried out during 2005 and 2006 with sun and shaded barley plants. The results showed that leaf area increased with leaf position on the main stem up to leaf position 5 for sun and leaf position 6 for shaded plants, and then declined towards flag leaves. Air temperature affected leaf appearance, mainly at the beginning of the growing season. A positive correlation between leaf expansion duration (LED) and accumulated temperature sum was measured for both variants, LED linearly increased with temperature sum. Leaf expansion rate (LER) showed a similar dependence on accumulated air temperatures in both light variants. A strong relation was found between soil temperature and LER for the first four leaves of the main stem of shaded plants in 2006. In shaded environment the higher LER was associated with lower accumulated irradiance sum when light restriction supported an increase of leaf elongation and final leaf length.

scholarly journals 860 PB 539 GROWTH RESPONSES OF CULANTRO (Eryngium foetidum L.) TO GIBBERELLIC ACID SPRAYS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 556g-557
Author(s):  
Christopher Ramcharan
Keyword(s):  
Chlorophyll Content ◽  
Latin American ◽  
Leaf Growth ◽  
Market Value ◽  
Leaf Length ◽  
Growth Responses ◽  
Eryngium Foetidum ◽  
Apparent Decrease ◽  
Flower Growth ◽  
The Tropics

Culentro, an umbelliferous aromatic saponin-containing biennial herb native of Central America and the West Indies is a major ingredient of many West Indian and Latin American dishes. Although closely related to the Asian culinary herb - cilantro or coriander, culantro is mainly prized for its green serrate spatulate-shaped leaves the main source of its oil. Like many other umbelliferoids under high temperatures and long summer days of the tropics culantro produces large umbel inflorescences and seedheads which are labor-intensive to remove, retard leaf growth and hence decrease the market value of the plant. Preliminary studies using ProGibb sprays from 50 to 200 ppm to 3- to 4-month old culantro plants grown under 53% shade showed increased leaf growth and chlorophyll content response to increasing levels of ProGibb. Maximum leaf length, fresh leaf weight, chlorophyll content and decreased flower growth were obtained at 100 ppm spray application. Treated plants remained in a vegetative phase for almost two years when vegetative side shoots were established. Postharvest observations showed no apparent decrease in shelf life nor loss of characteristic leaf aroma in leaves harvested from GA-treated plants. Inflorescences from sprayed plants were highly reduced in size, had leaf-like appearance and produced characteristic culantro aroma Indicating that they may also be utilized in culanto cuisines.

Sign in / Sign up

Export Citation Format

Share Document