The relationship between leaf growth and induction of flowering in long-day plants (LDP)

1961 ◽  
Vol 48 (4) ◽  
pp. 108-108 ◽  
Author(s):  
Roderick G. Thomas
Keyword(s):  
Leaf Growth ◽  
Long Day ◽  
Long Day Plants ◽  
The Relationship

scholarly journals Quantification of Airborne Inoculum as an Aid in the Management of Leaf Blight of Onion Caused by Botrytis squamosa

Plant Disease ◽  
2005 ◽  
Vol 89 (7) ◽  
pp. 726-733 ◽  
Author(s):  
O. Carisse ◽  
H. A. McCartney ◽  
J. A. Gagnon ◽  
L. Brodeur
Keyword(s):  
Leaf Growth ◽  
Control Plot ◽  
Leaf Blight ◽  
Yield Reduction ◽  
Lesion Development ◽  
Botrytis Squamosa ◽  
Airborne Inoculum ◽  
Significant Yield ◽  
Epidemic Development ◽  
The Relationship

Botrytis leaf blight, caused by Botrytis squamosa, is a common and frequently damaging disease of onion crops, but the severity of epidemics varies widely from year to year. The disease is initiated and spread by airborne conidia. The relationship between airborne conidium concentration (ACC) and lesion development was studied in the field. A linear relationship was found between ACC and number of lesions per leaf: ACC values of 10 to 15 and 25 to 35 conidia m-3 were associated with 1 and 2.5 lesions per leaf, respectively. In 2000 and 2001, at three sites, four different criteria were used to start a fungicide spray program and their effect on epidemic development was compared with that of a grower's conventional schedule. The criteria were: at the fourth-true-leaf growth stage; according to an inoculum production index; when the ACC reached 10 to 15 conidia m-3; and when the ACC reached 25 to 35 conidia m-3. A nonsprayed control plot was included in the trial. Fungicide programs started when the ACC reached 10 to 15 conidia m-3 were as effective as the conventional program, but used fewer sprays. A fungicide spray program based on measurements of ACC and disease severity was evaluated in 2002 and 2003 in five and three commercial onion fields, respectively. At each site, half of the field was sprayed according to the grower's schedule and, in the other half, fungicide sprays were initiated when a threshold of 10 to 15 conidia m-3 or five lesions on the lower leaf (whichever came first) was reached. Overall, the number of fungicide applications was reduced by 75 and 56% in 2002 and 2003, respectively, without causing significant yield reduction. In both years, the reduction in number of fungicide applications was due mainly to the delay in initiation of the fungicide program.

scholarly journals Leaf phenology, growth and photosynthesis in Pseudobombax munguba (Malvaceae)

Revista CERES ◽  
2019 ◽  
Vol 66 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ricardo Antonio Marenco ◽  
Francinete de Freitas Sousa ◽  
Marcilia Freitas de Oliveira
Keyword(s):  
Stomatal Conductance ◽  
Leaf Growth ◽  
Leaf Expansion ◽  
Leaf Phenology ◽  
Diameter Growth ◽  
Relative Growth ◽  
Adult Tree ◽  
Leaf Shedding ◽  
Tree Leaf ◽  
The Relationship

ABSTRACT Munguba (Pseudobombax munguba) is a tree often found in low-land forests of the Amazon region, and there is a paucity of data regarding its ecophysiology. The aim of this work was to determine photosynthetic rates and growth of munguba saplings and to describe leaf phenology of a munguba tree. In greenhouse-grown saplings, diameter growth, leaf expansion, photosynthesis and stomatal conductance were determined. To describe the relationship between photosynthesis and leaf expansion, regression analysis was used. It was also described the leaf phenology of an adult tree by observing foliage changes at one-week intervals for two years. The leaves completed their expansion in 18 days, and leaf greening was completed in 40 days. Photosynthesis positively correlated with leaf expansion, but there was no correlation between stomatal conductance and leaf growth. Growth in diameter was 1.8 mm month‒1. Relative growth rate was low, 0.010 g g-1 day-1. In the adult tree, leaf shedding was concentrated in July-August and by the second week of September the tree had already produced new leaves. Leaf longevity of munguba is about 11 months. It is hypothesized that leaf phenology of munguba is associated with the increased solar radiation of the dry season.

Variability in photoperiod and the inhibition of flowering in a high latitude population of Saxifraga rivularis

1981 ◽  
Vol 59 (3) ◽  
pp. 388-391 ◽  
Author(s):  
J. A. Teeri ◽  
S. J. Tonsor
Keyword(s):  
High Latitude ◽  
High Intensity ◽  
Dark Period ◽  
Controlled Environment ◽  
Photoperiodic Control ◽  
Incandescent Light ◽  
Devon Island ◽  
Low Intensity ◽  
Long Day ◽  
Long Day Plants

A population of Saxifraga rivularis L. collected at Truelove Lowland, Devon Island, N.W.T., Canada (75°41′ N) exhibits a photoperiodic control of flowering in controlled environment chambers. The plants respond in a manner typical of long-day plants with flowering inhibited by either a 6-h daily dark period, or by a 6-h daily low intensity irradiance regime of incandescent light. The inhibition of flowering by 6 h day−1 of incandescent light does not occur if the incandescent light is given in twelve 0.5-h doses, each followed by 1 h of red-rich high intensity irradiance.

Maize AUXIN-BINDING PROTEIN 1 and AUXIN-BINDING PROTEIN 4 impact on leaf growth, elongation, and seedling responsiveness to auxin and light

Botany ◽  
2012 ◽  
Vol 90 (10) ◽  
pp. 990-1006 ◽  
Author(s):  
Dejana Jurišić-Knežev ◽  
Mária Čudejková ◽  
David Zalabák ◽  
Marta Hlobilová ◽  
Jakub Rolčík ◽  
...  
Keyword(s):  
Binding Protein ◽  
Leaf Growth ◽  
Red Light ◽  
Maize Seedlings ◽  
Exogenous Auxin ◽  
Auxin Binding ◽  
Auxin Binding Protein ◽  
Auxin Binding Proteins ◽  
The Relationship

In maize, at least five auxin-binding proteins (ABPs) have been identified, yet their functions remain unclear. The present study reports the use of maize abp1, abp4, and abp1abp4 mutants to investigate the role of ABPs during maize growth and development. Single and double abp mutant plants grown in a greenhouse differ from the wild type (WT) in their leaf declination and leaf blade growth. The effect of the dark (D), blue light (BL), red light (RL), and exogenous auxin on the development of mutant seedlings was also studied. Relative to WT, etiolated mutant seedlings were shorter and showed a reduced responsiveness to exogenous auxin. In BL or RL, the responsiveness of maize seedlings to auxin was distinctly less than in D. The reducing effect of light on seedling responsiveness to auxin is mediated at least by phytochromes. The suppression of ABP1 and (or) ABP4 led to a distinct accumulation of free indole-3-acetic acid (IAA) in etiolated and light-grown seedling organs. We concluded that ABP1 and ABP4 participate in the growth of maize seedlings, mediate seedling responses to auxin, and interact with light signaling pathway(s). We also deduce a functional interaction between ABP1 and ABP4, which is that the relationship between them is light-, organ- and response-dependent.

scholarly journals Specific Functions of Red, Far Red, and Blue Light in Flowering and Stem Extension of Long-day Plants

2001 ◽  
Vol 126 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Blue Light ◽  
Flower Development ◽  
Red Light ◽  
Wide Band ◽  
Extension Growth ◽  
Photon Flux ◽  
Flower Initiation ◽  
Stem Extension ◽  
Long Day ◽  
Long Day Plants

For many long-day plants (LDP), adding far red light (FR, 700 to 800 nm) to red light (R, 600 to 700 nm) to extend the day or interrupt the night promotes extension growth and flowering. Blue light (B, 400 to 500 nm) independently inhibits extension growth, but its effect on flowering is not well described. Here, we determined how R-, FR-, or B-deficient (Rd, FRd, or Bd, respectively) photoperiods influenced stem extension and flowering in five LDP species: Campanula carpatica Jacq., Coreopsi ×grandiflora Hogg ex Sweet, Lobelia ×speciosa Sweet, Pisum sativum L., and Viola ×wittrockiana Gams. Plants were exposed to Rd, FRd, Bd, or normal (control) 16-hour photoperiods, each of which had a similar photosynthetic (400 to 700 nm) photon flux. Compared with that of the control, the Rd environment promoted extension growth in C. carpatica (by 65%), C. ×grandiflora (by 26%), P. sativum (by 23%), and V. ×wittrockiana (by 31%). The FRd environment suppressed extension growth in C. ×grandiflora (by 21%), P. sativum (by 17%), and V. ×wittrockiana (by 14%). Independent of the R: FR ratio, the Bd environment promoted stem extension (by 10% to 100%) in all species, but there was little or no effect on flowering percentage and time to flower. Extension growth was generally linearly related to the incident wide band (100 nm) R: FR ratio or estimated phytochrome photoequilibrium except when B light was specifically reduced. A high R: FR ratio (i.e., under the FRd filter) delayed flower initiation (but not development) in C. carpatica and C.×grandiflora and inhibited flower development (but not initiation) in V.×wittrockiana. Therefore, B light and the R: FR ratio independently regulate extension growth by varying magnitudes in LDP, and in some species, an FRd environment can suppress flower initiation or development.

scholarly journals Photoperiod, Juvenility, and High Intensity Lighting Affect Flowering and Cut Stem Qualities of Campanula and Lupinus

HortScience ◽  
2001 ◽  
Vol 36 (7) ◽  
pp. 1192-1196 ◽  
Author(s):  
Todd J. Cavins ◽  
John M. Dole
Keyword(s):  
High Intensity ◽  
Stem Diameter ◽  
Stem Length ◽  
Leaf Stage ◽  
Long Day ◽  
Supplemental Lighting ◽  
Long Day Plants

Campanula medium L. `Champion Blue' and `Champion Pink' and Lupinus hartwegii Lindl. `Bright Gems' were grown in 8- or 16-h initial photoperiods, transplanted when 2-3, 5-6, or 8-9 true leaves developed, and placed under 8-, 12-, or 16-h final photoperiods. The lowest flowering percentage for `Champion Blue' (<1%) and `Champion Pink' (16%) resulted from plants grown in the 8-h photoperiod continuously. One hundred percent flowering occurred when Campanula were grown in the 16-h final photoperiod, indicating that `Champion Blue' and `Champion Pink' are long-day plants. Plants grown initially in the 8-h and finished in the 16-h photoperiod had the longest stems. Stem diameter was generally thickest for plants grown in the 8-h compared with the 16-h initial photoperiod. However, the 8-h initial photoperiod delayed anthesis compared with the 16-h initial photoperiod. `Champion Blue' and `Champion Pink' plants transplanted at the 2-3 leaf stage from the 16 hour initial to the 8-h final photoperiod had flowering percentages of 64% and 63%, respectively; however, when transplanted at the 8-9 leaf stage, plants were fully mature and 100% flowering occurred indicating that all plants were capable of flowering. In year 2, plants receiving high intensity discharge (HID) supplemental lighting during the 16-h initial photoperiod reached anthesis in 11 fewer days compared with plants not receiving HID supplemental lighting. High profits were obtained from Campanula grown in the 8-h initial photoperiod and transferred at 5-6 true leaves into the 16-h final photoperiod. Lupinus hartwegii plants had a high flowering percentage (96% to 100%) regardless of photoperiod or transplant stage. The 16-h final photoperiod decreased days to anthesis compared with the 8- or 12-h final photoperiod indicating that L. hartwegii is a facultative long-day plant. Increasing length of final photoperiod from 8- to 16-h increased stem length. Juvenility was not evident for Lupinus in this study. In year 2, Lupinus cut stems were generally longer and thicker when given HID supplemental lighting, especially when grown in the 8- or 12-h final photoperiod. Supplemental lighting also reduced days to anthesis. Highest profits were generally produced from Lupinus plants grown with supplemental HID lighting (during the initial photoperiod) until 8-9 true leaves had developed.

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