Fatty Acid Concentration in Portulaca oleraceae L. is Altered by Photosynthetic Photon Flux

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 480d-480
Author(s):  
U.R. Palaniswamy ◽  
R.J. McAvoy ◽  
B.B. Bible

Purslane (Portulaca oleraceae L.) seedlings were grown under an instantaneous photosynthetic photon flux (PPF) of 299 or 455 μmol·m–2·s–1 for a daily duration of either 8, 12, 16, or 20 h. Thus plants were exposed to a daily PPF of 8.6, 12.9, 17.2, and 21.5 mol·m–2·d–1 in the low PPF treatment (299 μmol·m–2·s–1) and 13.1, 19.7, 26.2, and 32.8 mol·m–2·d–1 in the high PPF treatment (455 μmol·m–2·s–1). All treatments received a 20-h photoperiod using a PPF of ≈5 μmol·m–2·s–1. At low PPF, purslane grown under 16-h PPF duration produced the highest concentration of total fatty acid (TFA), linoleic acid (LA), and linolenic acid (LNA) per unit leaf dry mass (DM) and leaf area; but at high PPF, the concentration of these compounds was highest under 8- and 12-h PPF duration. Trend analysis indicated that maximum TFA, LA, and LNA concentrations occurred with a PPF of 14.1, 16.9 and 17.2 mol·m–2·d–1 respectively; and protein, chlorophyll, and LNA concentrations in thylakoid membranes were maximized at PPF of 21.8, 19.9, and 16.1 mol·m–2·d–1, respectively. LNA as percent of TFA was unaffected by treatment. DM increased with PPF up to the highest PPF exposure of 32.8 mol·m–2·d–1.

HortScience ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 988-991 ◽  
Author(s):  
Yoshiaki Kitaya ◽  
Genhua Niu ◽  
Toyoki Kozai ◽  
Maki Ohashi

Lettuce (Lactuca sativa L. cv. Summer-green) plug transplants were grown for 3 weeks under 16 combinations of four levels (100, 150, 200, and 300 μmol·m-2·s-1) of photosynthetic photon flux (PPF), two photoperiods (16 and 24 h), and two levels of CO2 (400 and 800 μmol·mol-1) in growth chambers maintained at an air temperature of 20 ±2 °C. As PPF increased, dry mass (DM), percent DM, and leaf number increased, while ratio of shoot to root dry mass (S/R), ratio of leaf length to leaf width (LL/LW), specific leaf area, and hypocotyl length decreased. At the same PPF, DM was increased by 25% to 100% and 10% to 100% with extended photoperiod and elevated CO2 concentration, respectively. Dry mass, percent DM, and leaf number increased linearly with daily light integral (DLI, the product of PPF and photoperiod), while S/R, specific leaf area, LL/LW and hypocotyl length decreased as DLI increased under each CO2 concentration. Hypocotyl length was influenced by PPF and photoperiod, but not by CO2 concentration. Leaf morphology, which can be reflected by LL/LW, was substantially influenced by PPF at 100 to 200 μmol·m-2·s-1, but not at 200 to 300 μmol·m-2·s-1. At the same DLI, the longer photoperiod promoted growth under the low CO2 concentration, but not under the high CO2 concentration. Longer photoperiod and/or higher CO2 concentration compensated for a low PPF.


2011 ◽  
Vol 57 (No. 9) ◽  
pp. 377-383 ◽  
Author(s):  
V. Bayramzadeh ◽  
P. Attarod ◽  
M.T. Ahmadi ◽  
S. Rezaee Amruabadi ◽  
T. Kubo

The relationships between climatic factors and anatomical characteristics of the vessel elements as well as different foliar traits were investigated in Fagus crenata seedlings originating from different provenances. Fagus crenata samples were prepared from Chichibu Research Forest of Tokyo University. In the present study, vessel number per mm<sup>2</sup>, average vessel diameter, vessel area percentage, vessel element length, percentages of perforation plate types, transpiration rate, stomatal conductance, leaf area, leaf thickness, leaf dry mass per unit leaf area, stomatal density and stomatal pore length were measured. Vessel number per mm<sup>2</sup>, vessel area percentage, stomatal conductance, transpiration rate, leaf thickness and leaf dry mass per unit leaf area showed a significant negative correlation with yearly, winter, spring and autumn precipitation. The majority of the studied characteristics were not related to the mean annual and seasonal temperatures of the original provenances. The results suggest that anatomical characteristics of vessel elements and different foliar traits in Fagus crenata are mainly influenced by the precipitation of the origins.


2001 ◽  
Vol 126 (5) ◽  
pp. 537-543 ◽  
Author(s):  
Usha R. Palaniswamy ◽  
Richard J. McAvoy ◽  
Bernard B. Bible

Purslane (Portulaca oleracea L.) is an excellent source of the essential fatty acid α-linolenic acid (LNA) but little is known of the effects of cultural conditions on LNA concentration. Purslane seedlings were grown under an instantaneous photosynthetic photon flux [PPF (400 to 700 nm)] of 299 or 455 μmol·m-2·s-1 for a daily duration of either 8, 12, 16, or 20 hours. Thus, plants were exposed to a daily PPF of 8.6, 12.9, 17.2, or 21.5 mol·m-2·d-1 in the low PPF treatment (299 μmol.m-2.s-1) and 13.1, 19.7, 26.2, or 32.8 mol·m-2·d-1 in the high PPF treatment (455 μmol·m-2·s-1). Plants in all treatments received a 20-hour photoperiod by providing ≈5 μmol·m-2·s-1 from incandescent lamps starting at the end of the photosynthetic light period. At low PPF, purslane grown under a 16 hour PPF duration produced the highest concentrations of total fatty acids (TFA) and LNA per unit leaf dry weight (DW), but at high PPF, concentrations of these compounds were highest under 8 and 12 hour PPF duration. Trend analysis indicated that maximum TFA and LNA concentrations occurred with a daily PPF of 14.1 and 17.2 mol·m-2·d-1, respectively; and in the thylakoids, protein, chlorophyll, and LNA concentrations peaked at a PPF of 21.8, 19.9, and 16.1 mol·m-2·d-1, respectively. LNA as a percentage of TFA was unaffected by treatment. Shoot DW increased with PPF up to the highest PPF exposure of 32.8 mol·m-2·d-1.


2003 ◽  
Vol 46 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Ivany Ferraz Marques Válio

Thirteen understorey species of a mesophyllous tropical forest were studied under two different photosynthetic photon flux densities (PPFD). Seedlings were grown in the glasshouse under 51% and 2.6% solar PPFD. Growth of the seedlings was evaluated by 1-) total height; 2-) leaf number; 3-) leaf dry mass;4-) stem dry mass; 5-) root dry mass; 6-) stem length/mass; 7-)shoot/root mass; 8-) percent allocation to leaf, stem and roots. For most of the parameters recorded, low PPFD drastically reduced growth. It seemed that the strategy of these understorey species was a reduction of growth under low PPFD saving energy for survival.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 637
Author(s):  
Paul Kusuma ◽  
Boston Swan ◽  
Bruce Bugbee

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).


1999 ◽  
Vol 34 (6) ◽  
pp. 944-952 ◽  
Author(s):  
Moacyr Bernardino Dias-Filho

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in Brazilian Amazonia, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. For both species leaf dry mass and leaf area per total plant dry mass, and leaf area per leaf dry mass were higher for low-light plants, whereas root mass per total plant dry mass was higher for high-light plants. High-light S. cayennensis allocated significantly more biomass to reproductive tissue than low-light plants, suggesting a probably lower ability of this species to maintain itself under shaded conditions. Relative growth rate (RGR) in I. asarifolia was initially higher for high-light grown plants and after 20 days started decreasing, becoming similar to low-light plants at the last two harvests (at 30 and 40 days). In S. cayennensis, RGR was also higher for high-light plants; however, this trend was not significant at the first and last harvest dates (10 and 40 days). These results are discussed in relation to their ecological and weed management implications.


2021 ◽  
Vol 45 ◽  
Author(s):  
Elen Silma Oliveira Cruz Ximenes ◽  
Andréa Carvalho da Silva ◽  
Adilson Pacheco de Souza ◽  
Josiane Fernandes Keffer ◽  
Alison Martins dos Anjos ◽  
...  

ABSTRACT Flame retardants are efficient in fighting wildfire; however, their environmental implications, especially regarding the vegetation, need to be clarified. This work aimed at assessing the effects of flame retardant on the initial growth of Schizolobium amazonicum. Treatments consisted in applying different flame retardant concentrations via substrate and leaf: Phos-Chek WD-881® (0, 3.00, 6.00, 8.00 and 10.00 mL L-1), Hold Fire® (0, 7.00, 9.00, 12.00 and 15.00 mL L-1) and water-retaining polymer Nutrigel® used as alternative retardant (0, 0.25, 0.50, 0.75 and 1.00 g L-1). Growth analyses were carried out to assess the effects of these substances (10 repetitions per treatment). The aliquot of 10.00 mL L-1 of Phos-Chek WD881 applied on the leaves led to an increase of 70% in leaf area and 15% in seedling height. The same Phos-Chek concentration favored height increase (32%) and total dry mass accumulation (33%) throughout time. The concentration of 15 mL L-1 of Hold Fire® applied on leaves, compromised 45% the accumulation of dry biomass in the seedling. Initially, 1.00 g L-1 of Nutrigel® applied via substrate led to an increase of 70% in leaf area, 29% in plant height, and 89% in leaf dry mass. Therefore, Phos-Chek applied on leaves favored shoot growth in S. amazonicum. Hold Fire® applied on leaves impaired biomass accumulation in seedlings. Nutrigel® applied on substrate does not cause long-lasting damage to the initial growth of S. amazonicum. The aliquot of 0.50 g L-1 administered via polymer leave had positive effect on seedling shoot.


2002 ◽  
Vol 127 (2) ◽  
pp. 290-296 ◽  
Author(s):  
Keith A. Funnell ◽  
Errol W. Hewett ◽  
Julie A. Plummer ◽  
Ian J. Warrington

Photosynthetic activity of individual leaves of Zantedeschia Spreng. `Best Gold' aff. Z. pentlandii (Wats.) Wittm. [syn. Richardia pentlandii Wats.] (`Best Gold'), were quantified with leaf expansion and diurnally, under a range of temperature and photosynthetic photon flux (PPF) regimes. Predictive models incorporating PPF, day temperature, and percentage leaf area expansion accounted for 78% and 81% of variation in net photosynthetic rate (Pn) before, and postattainment of, 75% maximum leaf area, respectively. Minimal changes in Pn occurred during the photoperiod when environmental conditions were stable. Maximum Pn (10.9μmol·m-2·s-1 or 13.3 μmol·g-1·s-1) occurred for plants grown under high PPF (694 μmol·m-2·s-1) and day temperature (28 °C). Acclimation of Pn was less than complete, with any gain through a greater light-saturated photosynthetic rate (Pmax) at high PPF also resulting in a reduction in quantum yield. Similarly, any gain in acclimation through increased quantum yield under low PPF occurred concurrently with reduced Pmax. It was concluded that Zantedeschia `Best Gold' is a shade tolerant selection, adapted to optimize photosynthetic rate under the climate of its natural habitat, by not having obligate adaptation to sun or shade habitats.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 397 ◽  
Author(s):  
Virupax C. Baligar ◽  
Marshall K. Elson ◽  
Alex-Alan F. Almeida ◽  
Quintino R. de Araujo ◽  
Dario Ahnert ◽  
...  

Cacao (Theobroma cacao L.) was grown as an understory tree in agroforestry systems where it received inadequate to adequate levels of photosynthetic photon flux density (PPFD). As atmospheric carbon dioxide steadily increased, it was unclear what impact this would have on cacao growth and development at low PPFD. This research evaluated the effects of ambient and elevated levels carbon dioxide under inadequate to adequate levels of PPFD on growth, physiological and nutrient use efficiency traits of seven genetically contrasting juvenile cacao genotypes. Growth parameters (total and root dry weight, root length, stem height, leaf area, relative growth rate and net assimilation rates increased, and specific leaf area decreased significantly in response to increasing carbon dioxide and PPFD. Increasing carbon dioxide and PPFD levels significantly increased net photosynthesis and water-use efficiency traits but significantly reduced stomatal conductance and transpiration. With few exceptions, increasing carbon dioxide and PPFD reduced macro–micro nutrient concentrations but increased uptake, influx, transport and nutrient use efficiency in all cacao genotypes. Irrespective of levels of carbon dioxide and PPFD, intraspecific differences were observed for growth, physiology and nutrient use efficiency of cacao genotypes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jing-Qiu Feng ◽  
Feng-Ping Zhang ◽  
Jia-Lin Huang ◽  
Hong Hu ◽  
Shi-Bao Zhang

In flowering plants, inflorescence characteristics influence both seed set and pollen contribution, while inflorescence and peduncle size can be correlated with biomass allocation to reproductive organs. Peduncles also play a role in water and nutrient supply of flowers, and mechanical support. However, it is currently unclear whether inflorescence size is correlated with peduncle size. Here, we tested whether orchids with large diameter peduncles bear more and larger flowers than those with smaller peduncles by analyzing 10 traits of inflorescence, flower, and leaf in 26 species. Peduncle diameters were positively correlated with inflorescence length and total floral area, indicating that species with larger peduncles tended to have larger inflorescences and larger flowers. We also found strongly positive correlation between inflorescence length and leaf area, and between total floral area and total leaf area, which suggested that reproductive organs may be allometrically coordinated with vegetative organs. However, neither flower number nor floral dry mass per unit area were correlated with leaf number or leaf dry mass per unit area, implying that the function between leaf and flower was uncoupled. Our findings provided a new insight for understanding the evolution of orchids, and for horticulturalists interested in improving floral and inflorescence traits in orchids.


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