Photosynthesis in Sitka Spruce. VIII. The Effects of Light Flux Density and Direction on the Rate of Net Photosynthesis and the Stomatal Conductance of Needles

1979 ◽  
Vol 16 (3) ◽  
pp. 919 ◽  
Author(s):  
J. W. Leverenz ◽  
P. G. Jarvis
Keyword(s):  
Stomatal Conductance ◽  
Flux Density ◽  
Light Flux ◽  
Net Photosynthesis ◽  
Sitka Spruce

scholarly journals Physiological responses of beet plants irrigated with saline water and silicon application

2020 ◽  
Vol 11 ◽  
pp. E3113
Author(s):  
José Sebastião de Melo Filho ◽  
Toshik Iarley da Silva ◽  
Anderson Carlos de Melo Gonçalves ◽  
Leonardo Vieira de Sousa ◽  
Mario Leno Martins Véras ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Concentration ◽  
Saline Water ◽  
Block Design ◽  
Essential Element ◽  
Net Photosynthesis ◽  
Crop Productivity ◽  
Experimental Unit ◽  
Randomized Block Design

Although not considered an essential element, silicon can be used to increase crop productivity, especially under stress conditions. In this sense, the objective was to evaluate the gas exchange of beet plants irrigated with saline water depending on the application of silicon. The experiment was conducted in a randomized block design, in a 5 x 5 factorial, referring to five levels of electrical conductivity of irrigation water (ECw): (0.5; 1.3; 3.25; 5.2 and 6.0 dS m-1) and five doses of silicon (0.00; 2.64; 9.08; 15.52 and 18.16 mL L-1), with six beet plants as an experimental unit. The effect of treatments on beet culture was evaluated at 30 and 60 days after irrigation with saline water from measurements of internal carbon concentration, stomatal conductance, net photosynthesis rate, instantaneous water use efficiency and instantaneous carboxylation efficiency using the LCpro+Sistem infrared gas analyzer (IRGA). Irrigation with saline water reduced the gas exchange of beet plants at 60 days after irrigation, but at 30 days after irrigation, the use of saline water increased stomatal conductance, transpiration rate and internal carbon concentration. The application of silicon decreased stomatal conductance, internal carbon concentration and efficiency in the use of water, but increased the rate of net photosynthesis, the rate of transpiration and instantaneous efficiency of carboxylation at 30 and 60 days after irrigation.

Effects of frozen storage duration and soil temperature on the stomatal conductance and net photosynthesis of Piceaglauca seedlings

1993 ◽  
Vol 23 (12) ◽  
pp. 2459-2466 ◽  
Author(s):  
George J. Harper ◽  
Edith L. Camm
Keyword(s):  
Stomatal Conductance ◽  
Soil Temperature ◽  
Carbon Fixation ◽  
Frozen Storage ◽  
Net Photosynthesis ◽  
Storage Duration ◽  
Growing Period ◽  
Soil Temperatures ◽  
Low Levels ◽  
And Storage

Nursery grown seedlings of Piceaglauca (Moench) Voss were stored frozen in the dark from approximately 10–31 weeks, thawed and grown for 28 days in a growth chamber at three soil temperatures (3, 7, and 11 °C). During the growing period gas exchange measurements were made every three days. Seedling net photosynthesis (pn) and stomatal conductance (gs) showed significant interactions between soil temperature and storage duration treatments. Soil temperature did not affect seedling gs or pn, though the degree and extent of storage duration effects were dependent on soil temperature. Recovery of gs occurred over a 4–7 day period from low levels after planting. Seedlings stored longer than 22 weeks showed lower rates of pn, than those stored for shorter durations. The lower pn in long-stored seedlings did not result from stomatal limitations to carbon fixation, as gs increased in seedlings stored >22 weeks.

Change in photosynthesis and water relations with age and season in Abiesamabilis

1984 ◽  
Vol 14 (1) ◽  
pp. 77-84 ◽  
Author(s):  
R. O. Teskey ◽  
C. C. Grier ◽  
T. M. Hinckley
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Relations ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Xylem Water Potential ◽  
Needle Age ◽  
Stressful Environment ◽  
Competitive Success ◽  
One Year

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.

INFLUENCE OF INSTANTANEOUS AND INTEGRATED LIGHT-FLUX DENSITY ON LEAF ANATOMY AND PHOTOSYNTHESIS

1979 ◽  
Vol 66 (8) ◽  
pp. 940-945 ◽  
Author(s):  
Brian F. Chabot ◽  
Thomas W. Jurik ◽  
Jean F. Chabot
Keyword(s):  
Flux Density ◽  
Leaf Anatomy ◽  
Light Flux

Genetic gains in grain yield, net photosynthesis and stomatal conductance achieved in Henan Province of China between 1981 and 2008

2011 ◽  
Vol 122 (3) ◽  
pp. 225-233 ◽  
Author(s):  
T.C. Zheng ◽  
X.K. Zhang ◽  
G.H. Yin ◽  
L.N. Wang ◽  
Y.L. Han ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Grain Yield ◽  
Net Photosynthesis ◽  
Henan Province ◽  
Genetic Gains

Growth during recovery evidences the waterlogging tolerance of forage grasses

2017 ◽  
Vol 68 (6) ◽  
pp. 574 ◽  
Author(s):  
R. A. Ploschuk ◽  
A. A. Grimoldi ◽  
E. L. Ploschuk ◽  
G. G. Striker
Keyword(s):  
Stomatal Conductance ◽  
Festuca Arundinacea ◽  
Global Climate ◽  
Leaf Gas Exchange ◽  
Recovery Period ◽  
Dactylis Glomerata ◽  
Net Photosynthesis ◽  
Forage Grasses ◽  
Waterlogging Tolerance ◽  
The Impact

Waterlogging is a stress of increasing importance for pastures as a consequence of global climate change. We evaluated the impact of waterlogging on four forage grasses with alleged differential tolerance, emphasising not only responses during the stress but also their reported ability to recover from it. To do this, 42-day plants of Dactylis glomerata, Bromus catharticus, Festuca arundinacea and Phalaris aquatica were subjected to 15-day waterlogging, followed by a subsequent 15-day recovery period. Shoot and root growth (i.e. RGR) during both periods, in addition to net photosynthesis and stomatal conductance rates during waterlogging were assessed. Sensitivity exhibited by D. glomerata and B. catharticus during waterlogging was related to growth arrest of roots – but not of shoots – along with a progressive fall in stomatal conductance and net photosynthesis. The injury during waterlogging preceded a negligible growth of shoots and roots, only evident during recovery in both species. By contrast, P. aquatica exhibited unaltered root RGR and promoted shoot RGR with no impact on leaf gas exchange during waterlogging; whereas F. arundinacea showed intermediate tolerance as root RGR was reduced during waterlogging, with stomatal conductance, net photosynthesis and shoot RGR remaining unaffected. These latter two species fully regained shoot and root RGR during recovery. So, P. aquatica and F. arundinacea seem more suitable for prone-to-flood lowlands, whereas to be conclusive about waterlogging tolerance, it is necessary to examine plant recovery as shown in D. glomerata and B. catharticus.

The impact of kaolin clay sprays on leaf gas exchange of Ginger Gold apple trees in New Brunswick

2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 1377-1381 ◽  
Author(s):  
J. P. Privé ◽  
L. Russell ◽  
A. LeBlanc
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
New Brunswick ◽  
Leaf Gas Exchange ◽  
Net Photosynthesis ◽  
Apple Orchard ◽  
Kaolin Clay ◽  
Gas Exchange Parameters ◽  
Leaf Physiology ◽  
The Impact

A field trial was conducted over two growing seasons in a Ginger Gold apple orchard in Bouctouche, New Brunswick, Canada to examine the impact of Surround (95% kaolin clay) on leaf gas exchange [net photosynthesis (Pn), stomatal conductance (gs), intercellular CO2 (Ci) and transpiration (E)]. In 2004, a greater rate of Pn and gs was achieved at the higher than at the lower frequency of Surround applications. This was particularly notable at leaf temperatures exceeding 35°C. In 2005, no significant (P ≤ 0.05) differences among leaf residue groupings [Trace (< 0.5 g m-2), Low (0.5 to 2 g m-2), and High (≥ 2 g m-2)] were found for the four leaf gas exchange parameters at leaf temperatures ranging from 25 to 40°C. It would appear that under New Brunswick commercial orchard conditions, the application of Surround favours or has no effect on leaf gas exchange. Key words: Surround, particle film, leaf physiology, photosynthesis, stomatal conductance, intercellular CO2, transpiration

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