Adaptive Responses of Field-Grown Common Lambsquarters (Chenopodium album) to Variable Light Quality and Quantity Environments

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Greta G. Gramig ◽  
David E. Stoltenberg
Keyword(s):  
Leaf Area ◽  
Light Quality ◽  
Stem Elongation ◽  
Reproductive Stage ◽  
Main Stem ◽  
Stem Length ◽  
Vegetative Stage ◽  
Common Lambsquarters ◽  
Full Sunlight ◽  
Partial Shade

Field experiments were conducted to determine whether exposure to reduced red : far-red light ratios (R : FR) typical of crop–weed environments was associated with adaptive changes in morphology, productivity, and fecundity of common lambsquarters. Plants were grown in reduced or ambient R : FR environments (both in full sunlight) until initiation of flowering, after which plants were grown in full sunlight or partial shade. At initiation of flowering, plants that had been exposed to reduced R : FR exhibited greater specific leaf area, stem elongation, main stem leaf area, specific stem length, and main stem mass compared with plants exposed to ambient R : FR. However, biomass allocation to stems, leaves, and roots did not differ between vegetative-stage R : FR treatments. At the end of flowering, morphology and productivity of plants exposed to partial shade did not differ between vegetative-stage R : FR treatments. In contrast, plants exposed to full sunlight during flowering after exposure to reduced R : FR during the vegetative stage had less total plant mass, less total leaf area, greater stem elongation, greater specific stem length, and a greater ratio of main stem to total stem mass compared with plants exposed to ambient R : FR during the vegetative stage. At physiological maturity, plants exposed to reduced R : FR during the vegetative stage and to partial shade during the reproductive stage had less total seed mass and fewer seeds compared with plants exposed to ambient R : FR during the vegetative stage and to partial shade during the reproductive stage. Fecundity of plants exposed to full sunlight during the reproductive stage did not differ between vegetative-stage R : FR treatments. These results indicate that exposure of common lambsquarters to reduced R : FR during the vegetative stage was maladaptive at later stages of growth in competitive environments, and suggest that interactions of light quality and quantity are important determinants of common lambsquarters fecundity.

scholarly journals Desempenho morfofisiológico de cultivares de soja de ciclo médio em condições de alagamento do solo

2017 ◽  
Vol 12 (3) ◽  
pp. 385
Author(s):  
Marcos Paulo Ludwig ◽  
Sandro De Oliveira ◽  
Luis Osmar Braga Schuch ◽  
Francisco Jesus Vernetti Junior ◽  
Rogério Seus ◽  
...  
Keyword(s):  
Plant Height ◽  
Reproductive Stage ◽  
Main Stem ◽  
Vegetative Stage ◽  
Cultivation Condition ◽  
Soil Flooding ◽  
Soybean Cultivars ◽  
Content Index ◽  
Crop Cycle ◽  
Stem Chlorophyll

<p>O aumento no cultivo de soja no Brasil têm atingido áreas antes utilizadas para outros fins, como em regiões de solos de várzea, estando assim, sujeita a eventuais alagamentos do solo. Este trabalho objetivou avaliar alterações morfofisiológicas em cultivares de soja de ciclo médio, em condições de alagamento do solo, nos estádios fenológicos vegetativo e reprodutivo para recomendação de cultivares. Os experimentos foram conduzidos na Estação Experimental de Terras Baixas, da Embrapa Clima Temperado em Capão do Leão, RS. Foram aplicados três sistemas de manejo da água: condição normal de cultivo (sem alagamento), alagamento no período vegetativo (V3/V4) e alagamento no período reprodutivo (R2/R3). As avaliações realizadas durante o ciclo da cultura foram: altura de plantas, diâmetro da haste principal, índice do teor de clorofila, fenologia e número de nós nas hastes por planta. O alagamento do solo reduz o número de nós na haste principal, reduzindo a estatura das plantas, sendo os efeitos mais acentuados quando o alagamento ocorre no estádio vegetativo. Além disso, o alagamento do solo no período reprodutivo promove aumento do diâmetro da haste principal. O alagamento do solo causa retardamento de ocorrência dos estádios fenológicos, bem como do ciclo total das cultivares de soja.</p><p align="center"><strong><em>Morphophysiological performance of medium cycle soybean cultivars under flooding</em></strong><strong><em></em></strong></p><pre><strong>Abstract: </strong>The increase in soybean cultivation in Brazil has reached areas previously used for other purposes, such as in regions of lowland soils, thus being subject to possible soil flooding. This study aimed to evaluate morphophysiological changes in medium cycle soybean cultivars, under soil flooding conditions, in the vegetative and reproductive stages to recommend cultivars.<strong> </strong>The experiments were conducted at the Estação Experimental de Terras Baixas, EMBRAPA Clima Temperado in the Capão do Leão city, RS. Three water management systems were applied: normal cultivation condition (without flooding), flooding in the vegetative stage (V3 / V4) and flooding during the reproductive stage (R2 / R3). During the crop cycle, plant height, diameter of the main stem, chlorophyll content index, phenology and number of nodes in the stem per plant were collected. On the basis of the results this study, it can be concluded that he flooding reduces the number of nodes on the main stem, reducing plant height, with the most pronounced effects when flooding occurs in the vegetative stage. Furthermore, flooding the reproductive stage promotes increased diameter of the main stem. Flooding causes delay of occurrence of phenological stages and the total cycle of soybean cultivars.</pre>

scholarly journals N:K RATIO FOR PHENOLOGICAL GROWTH STAGES OF NET MELON CULTIVATED IN NFT HYDROPONIC SYSTEM1

2020 ◽  
Vol 33 (1) ◽  
pp. 108-115
Author(s):  
CAMILA SENO NASCIMENTO ◽  
CAROLINA SENO NASCIMENTO ◽  
ARTHUR BERNARDES CECÍLIO FILHO
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Block Design ◽  
Dry Mass ◽  
Reproductive Stage ◽  
Vegetative Stage ◽  
Growth Stages ◽  
Second Stage ◽  
Randomized Block Design ◽  
Number Of Leaves

ABSTRACT The adequate ratio in the supply of nitrogen (N) and potassium (K) for each phenological growth stage of melon is fundamental for its growth and development with the maximization of the dry mass partition between the vegetative and reproductive parts. The objective of this study was to evaluate the influence of N and K concentrations in two phenological growth stages (vegetative and reproductive stage) of melon and obtain the best N:K ratio for each one. In the first stage, four concentrations of N (8, 11, 14 and 17 mmol L-1) and two concentrations of K (4 and 5 mmol L-1) were evaluated in a randomized block design in a 4 × 2 factorial scheme with five replicates. In the second stage, in a 2 × 2 factorial scheme, the combinations of the two concentrations of N that generated the best characteristics in the previous stage and two concentrations of K (4.5 and 9.0 mmol L-1) were evaluated. The increase of the N concentration in the vegetative stage promoted the increase of the N, P and S content of leaves and the reduction of K, Ca and Mg. Moreover, it increased the number of leaves, the height of the plant (vertically tutored) and the leaf area. Therefore, 17:5 mmol L-1 was considered as the best N:K ratio for the vegetative stage. In the second stage, there was no effect of N and K concentrations on leaf area, yield and fruit quality. So, 14:4.5 mmol L-1 was considered as the best N:K ratio for the reproductive stage.

scholarly journals Green light reduces elongation when partially replacing sole blue light independently from cryptochrome 1a

2020 ◽  
Author(s):  
Xue Zhang ◽  
Mehdi bisbis ◽  
Ep Heuvelink ◽  
Weijie Jiang ◽  
Leo F. M Marcelis
Keyword(s):  
Leaf Area ◽  
Blue Light ◽  
Stem Elongation ◽  
Green Light ◽  
Light Response ◽  
Biomass Accumulation ◽  
Photosynthetic Photon Flux Density ◽  
Stem Length ◽  
Photon Flux ◽  
Photon Flux Density

Abstract Although green light is often neglected it can have several effects on plant growth and development. Green light is probably sensed by cryptochromes (crys), one of the blue light photoreceptor families. The aim of this study is to investigate the possible interaction between green and blue light and the involvement of crys in the green light response of plant photomorphogenesis. We hypothesize that green light effects on morphology only occur when crys are activated by the presence of blue light. Wild-type Moneymaker (MM), cry1a mutant (cry1a) and two CRY2 overexpressing transgenic lines (CRY2-OX3 and CRY2-OX8) of tomato (Solanum lycopersicum) were grown in a climate chamber without or with green light (30 µmol m− 2 s− 1) on backgrounds of sole red, sole blue and red/blue mixture, with all treatments having the same photosynthetic photon flux density of 150 µmol m− 2 s− 1. Green light showed no significant effect on biomass accumulation, nor on leaf photosynthesis and leaf characteristics such as leaf area, specific leaf area, and chlorophyll content. However, in all genotypes, green light significantly decreased stem length on a sole blue background, whereas green light did not affect stem length on sole red and red/blue mixture background. MM, cry1a and CRY2-OX3/8 plants all exhibited similar responses of stem elongation to green light, indicating that cry1a, and probably cry2, is not involved in this green light effect. We conclude that partially replacing blue light by green light reduces elongation and that this is independent of cry1a.

scholarly journals Daylength, Light Quality, and Temperature Influence Growth and Development of Achimenes

HortScience ◽  
1992 ◽  
Vol 27 (12) ◽  
pp. 1269-1271 ◽  
Author(s):  
J.C. Vlahos ◽  
G.F.P. Martakis ◽  
E. Heuvelink
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Light Quality ◽  
Stem Elongation ◽  
Dry Weight ◽  
Temperature Influence ◽  
Growth Responses ◽  
Incandescent Light ◽  
Higher Temperature ◽  
Cultivar Responses

The effects of supplementary irradiance (20 μmol·s-1·m-2 for 6 hours) with incandescent light (I) or fluorescent compact gas-discharge lamps (CF) vs. a basic irradiance (96 μmol·s-1·m-2 for 12 h) with fluorescent (F) light at 17 or 25C was studied for Achimenes hybrids `Flamenco', `Hilda', and `Rosenelfe'. The additional I increased leaf area (LA) and plant dry weight (DW) in `Hilda' and `Rosenelfe' and promoted stem elongation in all three cultivars. Additional F had no effect on DW. However, depending on cultivar, responses for LA varied. An increase in the number of flowers was promoted only in `Rosenelfe' by I and CF compared with the control. In all cultivars, the supplementary CF, when compared with the I, reduced LA and DW. LA was significantly larger and DW higher at higher temperature, except for `Rosenelfe', where DW was not influenced and LA was smaller at the higher temperature. All three cultivars produced a longer stem and more flowers at the higher temperature. Calculated growth responses were influenced by an interaction between temperature and cultivar.

scholarly journals Does Green Really Mean Go? Increasing the Fraction of Green Photons Promotes Growth of Tomato but Not Lettuce or Cucumber

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 637
Author(s):  
Paul Kusuma ◽  
Boston Swan ◽  
Bruce Bugbee
Keyword(s):  
Leaf Area ◽  
Stem Elongation ◽  
Wavelength Region ◽  
Sole Source ◽  
Dry Mass ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Shade Avoidance ◽  
Crop Species ◽  
Blue Region

The photon flux in the green wavelength region is relatively enriched in shade and the photon flux in the blue region is selectively filtered. In sole source lighting environments, increasing the fraction of blue typically decreases stem elongation and leaf expansion, and smaller leaves reduce photon capture and yield. Photons in the green region reverse these blue reductions through the photoreceptor cryptochrome in Arabidopsis thaliana, but studies in other species have not consistently shown the benefits of photons in the green region on leaf expansion and growth. Spectral effects can interact with total photon flux. Here, we report the effect of the fraction of photons in the blue (10 to 30%) and green (0 to 50%) regions at photosynthetic photon flux densities of 200 and 500 µmol m−2 s−1 in lettuce, cucumber and tomato. As expected, increasing the fraction of photons in the blue region consistently decreased leaf area and dry mass. By contrast, large changes in the fraction of photons in the green region had minimal effects on leaf area and dry mass in lettuce and cucumber. Photons in the green region were more potent at a lower fraction of photons in the blue region. Photons in the green region increased stem and petiole length in cucumber and tomato, which is a classic shade avoidance response. These results suggest that high-light crop species might respond to the fraction of photons in the green region with either shade tolerance (leaf expansion) or shade avoidance (stem elongation).

Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Stem Elongation ◽  
Tree Height ◽  
Shoot Elongation ◽  
Main Stem ◽  
Tree Age ◽  
Precommercial Thinning ◽  
Two Factors ◽  
Artificial Inoculations

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

SEASONAL GROWTH CHARACTERISTICS OF LONG AND SHORT SHOOTS OF TAMARACK

1967 ◽  
Vol 45 (9) ◽  
pp. 1643-1651 ◽  
Author(s):  
J. Johanna Clausen ◽  
T. T. Kozlowski
Keyword(s):  
Seasonal Changes ◽  
Stem Elongation ◽  
Growth Characteristics ◽  
Weight Increase ◽  
Stem Length ◽  
Larix Laricina ◽  
Seasonal Growth ◽  
Long Shoots ◽  
Short Shoots ◽  
Food Reserves

Tamarack (Larix laricina (DuRoi) K. Koch) produces long shoots which bear two kinds of needles. Early needles are present in the bud and elongate rapidly after budbreak. Late needles, few of which are present in the bud, elongate later than early needles. Short shoots bear early needles only, and stem length seldom exceeds 1 mm. Seasonal changes in length and weight of needles and stems of both shoot types were measured. In long shoots, 75% of stem elongation, more than 70% of stem weight increment, and 65–70% of late needle elongation occurred after early needles were full-sized. Stem and late needle elongation ceased simultaneously, after which time needle weight decreased and stem weight increased. Early needles probably drew on food reserves while developing, and then themselves contributed to stem and late needle elongation. Final stem weight increase probably used photosynthate from both late and early needles of the current year.Shading of current and last year's needles showed that shoots in which photosynthesis was interrupted in this way produced shorter, lighter-weight stems than did control shoots.

scholarly journals Evaluation of Chlorimuron as a Growth Regulator for Peanut

1995 ◽  
Vol 22 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Wayne E. Mitchem ◽  
Alan C. York ◽  
Roger B. Batts
Keyword(s):  
Growth Regulator ◽  
Vegetative Growth ◽  
Lateral Branch ◽  
Internode Length ◽  
Main Stem ◽  
Stem Length ◽  
Vine Growth

Abstract Chlorimuron was evaluated as a growth regulator on peanut. Treatments included chlorimuron at a total of 8.8 g ai/ha applied once at 60,75, or 90 d after emergence (DAE) or in equal portions applied twice at 60 and 75, 60 and 90, or 75 and 90 DAE or three times at 60, 75, and 90 DAE. Daminozide at 950 g ai/ha applied 75 DAE was included as a comparison. In a year with excessive vine growth, daminozide and all chlorimuron treatments except 8.8 g/ha applied 90 DAE reduced cotyledonary lateral branch and main stem length at harvest 9 to 20 and 12 to 24%, respectively, due to suppression of internode length. Sequential applications of chlorimuron generally suppressed growth more than single applications. No improvement in row visibility at harvest was noted. In a dry year with limited vegetative growth, neither chlorimuron nor daminozide affected cotyledonary lateral branch or main stem length at harvest. Chlorimuron at 2.9 g/ha applied 60, 75, and 90 DAE reduced yield 18% at one of four locations; no other treatment affected yield. Chlorimuron at 8.8 g/ha applied 60 DAE or 4.4 g/ha applied 60 and 75 DAE reduced the percentage of fancy pods and extra large kernels at one or more locations. No treatment affected the percentage of total sound mature kernels. Results suggest chlorimuron has little to no potential for use as a growth regulator.

Changes in the responses to light quality during ontogeny in Chenopodium album

2003 ◽  
Vol 81 (2) ◽  
pp. 152-163 ◽  
Author(s):  
Humberto Fabio Causin ◽  
Renata D Wulff
Keyword(s):  
Plant Growth ◽  
Light Quality ◽  
Chenopodium Album ◽  
Intraspecific Variability ◽  
Reproductive Fitness ◽  
Stem Length ◽  
Shade Avoidance ◽  
Late Flowering ◽  
Total Leaf ◽  
Avoidance Responses

Morphological shade-avoidance responses have been hypothesized to be a form of adaptive plasticity to improve competition for light; however, little is known about their intraspecific variability and their effect on reproductive fitness. To compare plant responses either at a common age or at a common phenological stage, two experiments were conducted with early- and late-flowering Chenopodium album plants exposed to different red (660 nm) to far red (730 nm) ratios. In the first experiment, plant height and number of leaves were recorded at several times during the vegetative stage, and at the onset of flowering, each plant was harvested and other growth traits were measured. In the second experiment, three destructive harvests were performed across the whole plant cycle. Plant growth and development markedly differed between early- and late-flowering plants in all of the conditions tested. Light treatments significantly affected stem length, total leaf number, total leaf area, and relative allocation to leaf biomass. In all families, the response of stem elongation to light treatments decreased later in the development, while changes in the other plastic responses were mostly due to variations in plant growth. No significant treatment effect was found on relative biomass allocation to reproductive structures. However, individual seed mass significantly differed between certain groups, indicating that light quality can affect reproductive fitness through changes in traits other than fruit or seed set.Key words: Chenopodium album, fitness, intraspecific variability, phenotypic plasticity, red to far red ratio, shade-avoidance responses.

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