Effects of Photon Flux Density on Nutrient Productivity in Eucalyptus grandis Seedlings

1991 ◽  
Vol 18 (3) ◽  
pp. 307 ◽  
Author(s):  
MUF Kirschbaum
Keyword(s):  
Growth Rate ◽  
Flux Density ◽  
Relative Growth Rate ◽  
Eucalyptus Grandis ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Phosphorus Concentration ◽  
Phosphorus Addition ◽  
Relative Growth ◽  
Nutrient Productivity

In plants in which growth is limited by the availability of phosphorus, phosphorus productivity is defined as the plants' relative growth rate divided by their internal phosphorus concentration. An experiment was conducted to assess whether phosphorus productivity was dependent on photon flux density, or whether photon flux density only set an upper maximum relative growth rate below which phosphorus productivity remained constant with changing photon flux density. Eucalyptus grandis seedlings were grown in growth units in which plants were suspended in air while continuously being sprayed with nutrient solution (aeroponic system). Plants were grown at five different relative phosphorus addition rates, and under natural lighting over the period from late summer to mid-winter when daily photon flux density decreased from about 30 to 10 mol quanta m-2 d-1. Relative growth rate was then plotted as a function of internal phosphorus concentration for a series of harvests. For the three highest relative phosphorus addition rates, there was a negative relationship between relative growth rate and internal phosphorus concentration. For the two lowest phosphorus addition rates, the internal phosphorus concentration increased throughout the experiment, while relative growth rate remained almost constant. This meant that phosphorus productivity changed throughout the experiment. When phosphorus productivity was expressed as a function of daily photon flux density, a linear relationship between phosphorus productivity and photon flux density was obtained. That relationship had a positive intercept on the axis of photon flux density which was interpreted as the plants' light compensation point. This finding has important implications for applications of the concept of nutrient productivity to the modelling of ecosystems in which growth is limited by nutrient availability.

Underwater light climate and the growth and pigmentation of planktonic blue-green algae (Cyanobacteria) II. The influence of light quality

1986 ◽  
Vol 227 (1248) ◽  
pp. 381-393 ◽  
Keyword(s):  
Growth Rate ◽  
Flux Density ◽  
Green Algae ◽  
White Light ◽  
Light Quality ◽  
Red Light ◽  
Green Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Blue Green Algae

The influence of light quality on the growth and chlorophyll and phycobiliprotein composition of eight strains of planktonic blue-green algae has been investigated. Growth rate in chromatic (red, green, blue) light (12 μE m -2 s -1 ) (1 μE = 6 × 10 17 photons) is a general function of the light absorption capacity of the cell. In all strains examined growth rate is enhanced in red light, and in Oscillatoria redekei and Gloeotrichia echinulata CC1 it exceeds the maximum growth rate possible in white light of a higher photon flux density under otherwise similar experimental conditions. In green light the growth rate of six phycocyanin-rich strains is approximately 60–75% of that in white light (12 μE m -2 s -1 ), but growth rate is enhanced in O. agardhii 7821 and G. echinulata CC1, which synthesize the green-light-absorbing phycobiliprotein, phycoerythrin. With the exception of these two phycoerythrin-producing strains, incubation in blue light results in a pronounced reduction in growth rate, which in the majority of strains is associated with a specific decline in cell chlorophyll concentrations. In all strains cell chlorophyll and phycobiliprotein content is similar in both white and green light. Associated with the enhancement of growth rate in red light there is a general decline in cell pigment concentrations. An increase in the cell chlorophyll: phycobiliprotein ratio also occurs in a number of strains in red light. This qualitative variation in pigmentation occurs where growth rate is at or near its maximum rate and in Gloeotrichia echinulata CC1 is the result of a specific reduction in the rate of phycoerythrin synthesis. In contrast to other blue-green algae capable of chromatic adaptation, the modulation of phycoerythrin synthesis in this strain is influenced considerably by the photon flux density of red light.

Modelling Nitrogen Uptake in Ingestad Units Using Michaelis-Menten Kinetics

1995 ◽  
Vol 22 (5) ◽  
pp. 823 ◽  
Author(s):  
PJ Sands ◽  
PJ Smethurst
Keyword(s):  
Growth Rate ◽  
Nutrient Uptake ◽  
Flux Density ◽  
Relative Growth Rate ◽  
Nitrogen Uptake ◽  
Nutrient Flux ◽  
Uptake Kinetics ◽  
Uptake Kinetic ◽  
Relative Growth ◽  
Nitrogen Concentrations

The concept of nutrient flux density was developed to grow plants at a controlled and stable relative growth rate whilst maintaining a constant internal concentration of a limiting nutrient. The method requires frequent and exponentially increasing additions of nutrients to replenish uptake. In developing this approach there has been little reference to Michaelis-Menten-like nutrient uptake kinetics for characterising uptake by roots. This paper applies a simple model of nitrogen-limited plant growth using Michaelis-Menten uptake kinetics to data from previously published experiments based on the nutrient flux density approach. It is shown that the model can indeed reproduce key features of experiments: (1) plant relative growth rate equals nitrogen relative addition rate up to a limit; (2) when nitrogen uptake kinetic parameters are within the range reported in the literature, this limiting growth rate agrees with that observed; and (3) solution nitrogen concentrations are consistent with those published. We suggest that the understanding of nutrient uptake and utilisation by plants could be advanced by jointly considering these two approaches.

Effect of Photon Flux Density and Temperature on the Production of Halogenated Monoterpenes by Plocamium cartilagineum (Plocamiaceae, Rhodophyta)

2004 ◽  
Vol 59 (9-10) ◽  
pp. 679-683 ◽  
Author(s):  
Rodrigo Palma ◽  
Mario Edding ◽  
Juana Rovirosa ◽  
Aurelio San-Martín ◽  
Victor H. Argandoña
Keyword(s):  
Growth Rate ◽  
Marine Alga ◽  
Effect Of Temperature ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Relative Growth ◽  
Halogenated Monoterpenes ◽  
Different Temperatures ◽  
The Relationship ◽  
Plocamium Cartilagineum

Abstract The effect of different photon flux densities (PFD) and temperatures on the relative growth rate (RGR) and the concentration of three halogenated monoterpenes in samples of Plocamium cartilagineum L.( Dixon), a marine alga (Rhodophyceae), were studied. The highest RGR (22.8 ± 0.04 d-1) was obtained at 15 °C and 41 μmol m-2 s-1 of PFD and the lowest (18.0 ± 0.2 d-1) was obtained at 18 °C and 120 μmol m-2 s-1. The different temperatures and light used in assays did not affect significantly the production of organic compounds. The production of mertensene and violacene was not affected significantly. However, compound 1 reached the highest concentration at 15 °C and 65 μmol m-2 s-1. The relationship between growth and production of monoterpenes of P. cartilagineum and the effect of temperature and the PFD were analyzed.

scholarly journals Interactions among cluster-root investment, leaf phosphorus concentration, and relative growth rate in two Lupinus species

2015 ◽  
Vol 102 (9) ◽  
pp. 1529-1537 ◽  
Author(s):  
Xing Wang ◽  
Erik J. Veneklaas ◽  
Stuart J. Pearse ◽  
Hans Lambers
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Phosphorus Concentration ◽  
Relative Growth ◽  
Cluster Root

scholarly journals LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh
Keyword(s):  
Growth Rate ◽  
Fold Increase ◽  
Photosynthetic Photon Flux Density ◽  
Ocimum Basilicum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
White Led ◽  
Experimental Conditions ◽  
Sweet Basil ◽  
Optimal Illumination

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

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