scholarly journals Irrigated Soybean Leaf Photosynthesis in the Humid Subtropical Midsouth

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
H. Arnold Bruns
Keyword(s):  
Stomatal Conductance ◽  
Growth Stage ◽  
Cultivar Differences ◽  
Photon Flux ◽  
Growth Stages ◽  
Base Temperature ◽  
Leaf Photosynthesis ◽  
Photosynthetic Photon Flux ◽  
Single Leaf ◽  
Soybean Leaf

Photosynthesis (CER (μmol CO2mleaf area-2 s−1)), stomatal conductance (gsw), and intercellular [CO2] (Ci) of soybean (Glycine maxL. Merr.) grown using the early soybean production system (ESPS) of the midsouth were determined. Three irrigated cultivars were grown using ESPS on Bosket (Mollic Hapludalfs) and Dundee (Typic Endoaqualf) soils in 2011 and 2012 at Stoneville, MS. Single leaf CER,gsw, andCiwere determined at growth stages R3, R4, and R5 using decreasing photosynthetic photon flux densities (PPFD,μmol m−2 s−1) beginning at 2000 PPFD and decreasing by 250 PPFD increments to 250 PPFD. Photosynthesis changes fit a quadratic polynomial for all fixed variables and range from ~6.0 and 9.0 CER at 250 PPFD and ~22.0 to 28.0 CER at 2000 PPFD. No cultivar differences in CER,gsw, orCiwere noted at any growth stage or site either year. In 2012, CER,gsw, andCiwere lower when measured at R5 than the two previous growth stages, which was not observed in 2011. The R5 sampling in 2012 had accumulated 39 to 70 more growing degree units at 10°C base temperature (GDU 10’s) than in 2011 and were likely more mature. Increased soybean yields from ESPS appear not to result from higher leaf CER.

scholarly journals Flag Leaf Photosynthesis and Stomatal Function of Grain Sorghum as Influenced by Changing Photosynthetic Photon Flux Densities

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
H. Arnold Bruns
Keyword(s):  
Flag Leaf ◽  
Grain Sorghum ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Growth Stages ◽  
Photosynthetic Photon Flux ◽  
Light Levels ◽  
Intrinsic Water Use Efficiency ◽  
N Fertility

Photosynthesis (A) and stomatal function research in grain sorghum (Sorghum bicolor (L.) Moench) is limited compared to other crops. Flag leaves from three plants of two hybrids, grown with added N-fertilizer of 0.0, 112, and 224 kg ha−1 near Elizabeth, MS, were measured for A and stomatal functions at growth stages GS6 and GS7. A Li-Cor LI-6400XT set at 355 µmol [CO2], a flow rate of 500 µmol s−1, and a 6400-02 LED light source were used to collect data. Light levels were initially set at 2200 µmol m−2 s−1 indicated photosynthetic photon flux density (PPFD), A was allowed to stabilize, data was recorded, indicated PPFD level was reduced by 200 µmol m−2 s−1, and the process was repeated to a level of 200 µmol m−2 s−1. At GS6 all data were unaffected by N-fertility, hybrids, or years. Data on Ci at GS6 indicated A declines faster with decreasing PPFD than gs. Intrinsic water use efficiency (IWUE) data supports prior research showing stomata function more to regulate water loss and only marginally limit A. Nitrogen fertility was null on A and stomatal functions and minimal on yield; thus no attempt was made to correlate yield with these data.

Studies on the physiology and propagation of the ostrich fern, Matteuccia struthiopteris

1985 ◽  
Vol 86 ◽  
pp. 153-159
Author(s):  
Robert K. Prange
Keyword(s):  
Flux Density ◽  
Water Availability ◽  
Water Status ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Base Temperature ◽  
Photosynthetic Photon Flux ◽  
Fertile Frond ◽  
Rate Of Emergence

SynopsisThe effect of photosynthetic photon flux density (PPFD), water, temperature and nutrition on frond emergence, vegetative frond production, fertile frond production, vegetative propagation and dormancy is examined. Ostrich fern plants will not break winter dormancy until they have received a minimum amount of cold exposure below a base temperature which is above 5.8°C and may be as high as 20°C. After the plants have received their chilling requirement, vegetative frond emergence does not occur until temperatures at or above ca. 9.3°C are reached. Percent germination and rate of emergence increases up to ca. 24°C. Photosynthetic photon flux density, water availability and mineral nutrition can affect both vegetative and fertile frond production but water availability appears to be the most critical. A mild water stress of −0.15MPa can have significant effects on water status and gas exchange in fronds. Sporophyte plants for field production have been produced vegetatively from detached meristems occurring naturally on the rhizomes, and through fertilization of axenic gametophytes.

scholarly journals Optimization of Photosynthetic Photon Flux Density and Light Quality for Increasing Radiation-Use Efficiency in Dwarf Tomato under LED Light at the Vegetative Growth Stage

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 121
Author(s):  
Xinglin Ke ◽  
Hideo Yoshida ◽  
Shoko Hikosaka ◽  
Eiji Goto
Keyword(s):  
Vegetative Growth ◽  
Growth Stage ◽  
Light Quality ◽  
Dry Mass ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Use Efficiency ◽  
Radiation Use

Dwarf tomatoes are advantageous when cultivated in a plant factory with artificial light because they can grow well in a small volume. However, few studies have been reported on cultivation in a controlled environment for improving productivity. We performed two experiments to investigate the effects of photosynthetic photon flux density (PPFD; 300, 500, and 700 μmol m−2 s−1) with white light and light quality (white, R3B1 (red:blue = 3:1), and R9B1) with a PPFD of 300 μmol m−2 s−1 on plant growth and radiation-use efficiency (RUE) of a dwarf tomato cultivar (‘Micro-Tom’) at the vegetative growth stage. The results clearly demonstrated that higher PPFD leads to higher dry mass and lower specific leaf area, but it does not affect the stem length. Furthermore, high PPFD increased the photosynthetic rate (Pn) of individual leaves but decreased RUE. A higher blue light proportion inhibited dry mass production with the same intercepted light because the leaves under high blue light proportion had low Pn and photosynthetic light-use efficiency. In conclusion, 300 μmol m−2 s−1 PPFD and R9B1 are the recommended proper PPFD and light quality, respectively, for ‘Micro-Tom’ cultivation at the vegetative growth stage to increase the RUE.

Effects of autumn sowing dates on growth and yield of indeterminate and determinate field beans (Vicia faba)

1990 ◽  
Vol 114 (3) ◽  
pp. 339-352 ◽  
Author(s):  
C. J. Pilbeam ◽  
P. D. Hebblethwaite ◽  
H. E. Ricketts ◽  
O. A. Hassan
Keyword(s):  
Vicia Faba ◽  
Growth And Yield ◽  
Cultivar Differences ◽  
Field Bean ◽  
Growth Stages ◽  
Base Temperature ◽  
Sowing Dates ◽  
Final Yield ◽  
The University ◽  
Field Beans

SUMMARYDeterminate forms of field bean (Vicia faba L.), because of their altered growth habit, may differ in phenology from indeterminate cultivars and so their responses to environmental conditions may necessitate different optimum sowing dates. This was studied in autumn-sown field beans at the University of Nottingham at Sutton Bonington by standard growth analysis techniques, final yield components and monitoring of crop growth stages in an indeterminate cultivar, Bourdon, and two determinate populations, 858 and 796 (provided by Plant Breeding International, Cambridge), in three consecutive seasons beginning in 1985/86.Bourdon yielded significantly more (2·4 t/ha, on average) than the determinate selections as a result of more pod-bearing nodes per stem and seeds per pod and a greater individual seed weight. There was, however, no correlation between seed yield and canopy size, either in total or during pod filling. Determinacy, contrary to expectation, did not increase harvest index. In fact, the reproductive stems of Bourdon had higher harvest indices than those of 858. The yield disadvantage of determinates was therefore exacerbated by the existence of reproductive stems, which, by prolonging the maturation phase, may also detract from a further potential benefit of the determinate habit, namely an increase in yield stability.There seemed to be no cultivar differences in the temperature requirement for the initiation of developmental processes. An average accumulation of 1239 °C days was required from sowing to flowering. Differences between this and other work in the calculated base temperature for flowering were cautiously explained by the lack of data distinguishing day and night temperature in this experiment and by the use of autumn-sown rather than spring-sown cultivars. It is also suggested that photoperiod may be important in initiating flowering.Both determinate and indeterminate forms gave the greatest seed yields from the earliest sowing dates.

scholarly journals Effects of changes in the photosynthetic photon flux density on net gas exchange of Citrus limon and Nicotiana tabacum

2004 ◽  
Vol 16 (2) ◽  
pp. 77-82 ◽  
Author(s):  
Carlos Pimentel ◽  
Rafael Vasconcelos Ribeiro ◽  
Mauro Guida dos Santos ◽  
Ricardo Ferraz de Oliveira ◽  
Eduardo Caruso Machado
Keyword(s):  
Nicotiana Tabacum ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Stomatal Closure ◽  
Woody Species ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Citrus Limon ◽  
Photosynthetic Photon Flux

The objective of this study was to evaluate the effects of changes in the photosynthetic photon flux density (PPFD) on net gas exchange of Citrus limon, a woody species, and Nicotiana tabacum, an herbaceous species. When PPFD was increased from 50 to 350 mumol.m-2.s-1 and returned to 50 mumol.m-2.s-1 after 60 min, the CO2 assimilation rate (A) increased and stabilized after 15 min in both species. Stomatal conductance (g s), however, continued to increase. After returning to low PPFD, A immediately diminished to a low value for both lemon and tobacco. Stomatal conductance of lemon diminished slowly over 60 min, whereas g s for tobacco took only 15 min to decrease. This difference in behavior is probably due to over-sensitivity of stomata of woody species, such as Citrus, when exposed to high light, retarding stomatal closure on return to low PPFD. Furthermore, when lemon, growing at a PPFD of 300 mumol.m-2.s-1, was submitted to a step increase of 600 mumol.m-2.s-1, there was an oscillatory behavior of A and g s requiring 150 min to stabilize. The causes of this behavior are discussed with respect to improved intrinsic water use efficiency by stomatal closure.

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