Effect of changes in carbohydrate concentration on the rate of net photosynthesis in mature leaves of Abies balsamea

1973 ◽  
Vol 51 (4) ◽  
pp. 751-758 ◽  
Author(s):  
C. H. A. Little ◽  
K. Loach
Keyword(s):  
Photosynthetic Rate ◽  
Abies Balsamea ◽  
Net Photosynthesis ◽  
Total Sugar ◽  
Starch Accumulation ◽  
Carbohydrate Concentration ◽  
Normal Period ◽  
Before And After ◽  
Rate Of Photosynthesis ◽  
Foliar Concentration

The hypothesis that photosynthate accumulation within a leaf inhibits the ongoing rate of photosynthesis was investigated in 6-year-old balsam fir trees. Rates of net photosynthesis and transpiration, and concentrations of starch, total sugar, chlorophyll, and water were measured in 1-year-old or fully expanded, current needles, and leaf resistances to carbon dioxide transfer were calculated. The several-fold rise and fall in the content of carbohydrate (mostly starch) that occurs naturally in 1-year-old needles before and after budbreak was correlated positively rather than negatively with the photosynthetic rate. Shading during the normal period of starch accumulation decreased the concentrations of both starch and total sugar, but did not increase photosynthesis. Continuous cooling of the base of a branch to 2 °C to inhibit translocation of photosynthate did not affect the photosynthetic rate during a 2-week period, nor did it cause carbohydrate accumulation, as measured at the end of the experiment. Removing a ring of bark from a branch base resulted in a large increase in the foliar concentration of starch (but not total sugar) and a small decrease in photosynthesis. However, the concomitant decrease in moisture content, not the accumulation of starch, was more probably the cause of the reduced photosynthesis. We conclude that the rate of photosynthesis in fir needles, at least under normal growing conditions, is not influenced by photosynthate accumulation.

scholarly journals The effect of copper fungicides on the rate of photosynthesis and the transpiration of hop plants

2011 ◽  
pp. 117-123
Author(s):  
Jaroslav Pokorny ◽  
Josef Pulkrábek ◽  
Karel Krofta ◽  
Josef Ježek
Keyword(s):  
Photosynthetic Rate ◽  
Copper Content ◽  
Copper Fungicides ◽  
Before And After ◽  
Elemental Copper ◽  
Rate Of Photosynthesis ◽  
Accredited Laboratory ◽  
Effect Of Copper ◽  
Copper Fungicide ◽  
Infrared Analyzer

The paper evaluates the effect of copper fungicide spraying on the rate of photosynthesis and transpiration of hops, the influence of spraying on the elemental copper content in the leaves and cones hop variety Agnus. Photosynthetic rate was measured by LC pro+ (infrared analyzer) in the Hop Research Institute Saaz in the field in some periods of 2008, 2009 and 2010. Dry cones and leaf samples (taken before and after application of copper fungicides) were analyzed in an accredited laboratory for elemental copper.

scholarly journals Greenhouse Covering Materials and Supplemental Lighting Affect Growth, Yield, Photosynthesis, and Leaf Carbohydrate Synthesis of Tomato Plants

2002 ◽  
Vol 127 (5) ◽  
pp. 819-824 ◽  
Author(s):  
Badrane M. Erhioui ◽  
André Gosselin ◽  
Xiuming Hao ◽  
Athanasios P. Papadopoulos ◽  
Martine Dorais
Keyword(s):  
Photosynthetic Rate ◽  
Growth Yield ◽  
Specific Weight ◽  
Starch Accumulation ◽  
Marketable Yield ◽  
Tomato Plants ◽  
Carbohydrate Concentration ◽  
Supplemental Lighting ◽  
Marketable Fruit ◽  
Growing Conditions

A study was conducted in mini-greenhouses covered with single-glass (glass), double inflated polyethylene film (D-poly), or rigid twin acrylic panels (acrylic) to determine the effects of covering materials and supplemental lighting (SL) (65 μmol·m-2·s-1 at 1 m from the ground, providing a 16-hour photoperiod) on growth, yield, photosynthesis, and leaf carbohydrate concentration of `Trust' greenhouse tomato plants (Lycopersicon esculentum Mill.). Regardless of the light treatment, the marketable yield (kg·m-2) and the number of fruit per square meter in D-poly houses were higher (P ≤ 0.05) by 15% to 16% and 13% to 17%, respectively, than in glasshouses. Under supplemental lighting (SL), similar results were observed in acrylic houses compared to glasshouses. Covering materials had no significant effect on photosynthesis and leaf chlorophyll (chl) concentration. SL increased the number of leaves (March) by 15% (P ≤ 0.05) in glasshouses, marketable fruit yield by 23% (P ≤ 0.01) in acrylic houses, leaf specific weight by 19% to 33% (P ≤ 0.05) in all houses, total chl concentration by 10% to 14% (P ≤ 0.01) in acrylic houses, and photosynthetic rate (March) by 22% (P ≤ 0.01) in glasshouses. Under nonsupplemental lighting (nonSL, daily solar radiation of 8.42 MJ·m-2), plant height in acrylic houses was significantly higher (P ≤ 0.05) than in glasshouses. Neither covering materials nor SL affected (P ≤ 0.05) dry matter allocation to the fruit. Results suggest that D-poly and acrylic houses with SL provide the best environment for the early yield (February to March) under southwestern Ontario growing conditions. The photosynthetic rate decreased (P ≤ 0.05) by 18% in acrylic, and 15% in D-poly and glasshouses after 2 months of growth under nonSL. Conversely, the decrease in carbon exchange rate was not significant in D-poly houses and glasshouses under SL. As a result, the photosynthesis decline observed in the present study could not be explained by leaf starch accumulation in March.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

Effects of sucrose on starch accumulation and rate of photosynthesis in Rosa cultured in vitro

1991 ◽  
Vol 25 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Montserrat Capellades ◽  
Raoul Lemeur ◽  
Pierre Debergh
Keyword(s):  
Starch Accumulation ◽  
Rate Of Photosynthesis

THE RELATIONSHIP BETWEEN CHLOROPHYLL CONTENT AND RATE OF PHOTOSYNTHESIS IN SOYBEANS

1977 ◽  
Vol 57 (1) ◽  
pp. 1-5 ◽  
Author(s):  
B. R. BUTTERY ◽  
R. I. BUZZELL
Keyword(s):  
Linear Regression ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Regression Line ◽  
Quadratic Equation ◽  
Chlorophyll Contents ◽  
Rate Of Photosynthesis ◽  
Highly Correlated ◽  
The Relationship ◽  
Selection Of

Photosynthetic rate of soybeans (on a leaf area basis, PA) estimated from the incorporation of 14CO2 under field conditions was highly correlated with chlorophyll content of the side leaflets of the same leaves. Among a collection of 48 cultivars, the linear regression of PA on chlorophyll content accounted for 44% of the variation, whereas with a selection of genotypes with various mutant chlorophyll genes, the regression accounted for 81%. When the data for the two tests were re-calculated relative to the check cv. Altona, a quadratic equation between PA and chlorophyll accounted for nearly 90% of the variation. When photosynthetic rate was expressed on a unit chlorophyll basis (Pc), no significant differences among lines were established in the cultivar test. In the mutants test, significant differences in Pc were established with higher values of Pc associated with lower chlorophyll contents; a linear regression accounted for 45% of the variation. Transformation of the data from both experiments relative to Altona allowed the fitting of a common regression line (quadratic) which accounted for 63% of the variation. We suggest that initial screening of progenies in a breeding program for high photosynthetic rate could be done by measuring chlorophyll content.

Water relations, photosynthetic capacity, and root/shoot partitioning of photosynthate as determinants of productivity in hybrid poplar

1989 ◽  
Vol 67 (6) ◽  
pp. 1689-1697 ◽  
Author(s):  
T. J. Tschaplinski ◽  
T. J. Blake
Keyword(s):  
Net Photosynthetic Rate ◽  
Biomass Production ◽  
Photosynthetic Rate ◽  
Populus Deltoides ◽  
Hybrid Poplar ◽  
Net Photosynthesis ◽  
Unit Leaf ◽  
Vigorous Growth ◽  
The Difference ◽  
Causal Sequence

Physiological determinants of productivity, including net photosynthesis, root/shoot partitioning of photosynthate, and leaf retention were investigated for three Populus deltoides Bartr. × nigra L. (DN 2, DN 22, DN 15) and two P. balsamifera L. × deltoides Bartr. (Jackii 4, Jackii 7) hybrids. Performance of the different hybrids was compared under controlled greenhouse conditions and in the field. There was a 2.4-fold difference in biomass production between the faster growing DN 2 and the slower growing DN 15 after 100 days growth in the greenhouse, and a 1.5-fold difference after the 1st year's growth in the field. When coppice regrowth of the two Jackii hybrids was compared after 143 days under field conditions, the biomass production of Jackii 4 was 2.2 times that of Jackii 7 and net photosynthetic rate per unit leaf area was 50 % higher than that of Jackii 7 over most of the summer. Many physiological and morphological factors contributed to the more vigorous growth of coppice DN 2 and Jackii 4. These included vigorous initial root growth relative to shoot growth, the ability to maintain higher xylem pressure potentials, net photosynthetic rate, and transpiration rate. These factors may have delayed leaf senescence and late-season photosynthetic decline of older leaves until later in the growing season. The possible causal sequence of physiological events contributing to the difference in productivity and the use of these factors for the early selection of productive hybrids or genotypes are discussed.

scholarly journals Dissemination of nutrition and healthy diet in the era of the COVID-19 pandemic

2021 ◽  
Vol 6 (4) ◽  
pp. 503-511
Author(s):  
Dhian Kartikasari ◽  
Lucky Radita Alma ◽  
Septa Katmawanti ◽  
Nurnaningsih Herya Ulfah ◽  
Indana Tri Rahmawati ◽  
...  
Keyword(s):  
Nutrition Education ◽  
Community Service ◽  
Female Students ◽  
Healthy Diet ◽  
Nutritional Knowledge ◽  
Post Intervention ◽  
Noticeable Increase ◽  
Normal Period ◽  
Before And After ◽  
Post Test

The purpose of this community service was to increase knowledge about healthy diet arrangements for female students during the new normal period.  A total of 21 female students participated in the socialization of balanced nutrition during the pandemic.  Nutrition outreach activities were carried out in the form of online webinars through zoom cloud meetings.  Before and after outreach activities, the measurement of knowledge before and after the intervention (2 times the measurement of post-intervention).  The research instrument used was a questionnaire in the google form.  From the results of this community service, it was found that the nutrition dissemination activities carried out had an impact in the form of increasing nutritional knowledge, especially related to balanced nutrition guidelines during the pandemic.  This shows that the subject's knowledge was increasing and the subject understands about nutrition education.  The most noticeable increase in knowledge was about the largest portion in balanced nutrition.  There was a difference between the results of the pre-test, post-test 1, and post-test 2.

scholarly journals Carbohydrate Injections as a Potential Option to Improve Growth and Vitality of Live Oaks

2009 ◽  
Vol 35 (3) ◽  
pp. 142-147
Author(s):  
Tomás Martínez-Trinidad ◽  
W. Todd Watson ◽  
Michael Arnold ◽  
Leonardo Lombardini ◽  
David Appel
Keyword(s):  
Chlorophyll Fluorescence ◽  
Root Growth ◽  
Isotope Composition ◽  
Net Photosynthesis ◽  
Growth Indices ◽  
Glucose Content ◽  
Quercus Virginiana ◽  
Carbohydrate Concentration ◽  
Live Oak ◽  
Potential Option

This study evaluates the effects of carbohydrate injections on the growth and vitality of live oak (Quercus virginiana P. Miller). Glucose, sucrose, or a 50:50 mixture of both carbohydrates at increasing concentrations [0, 40, 80, and 120 g/L (0, 5.3, 10.6, and 16.0 oz/gal)] were injected into live oaks. Trunk and root growth, net photosynthesis, root and twig carbohydrate concentration, and chlorophyll fluorescence were monitored. Isotope composition of twig and root samples was measured as an indicator of injected carbohydrate distribution. There were significant differences (P < 0.05) in trunk growth among types of carbohydrates, but no significant differences for carbohydrate concentrations. The mixtures of sucrose and glucose had the largest effect on growth compared to either sugar alone, suggesting that glucose and sucrose alone were used in processes other than trunk growth. 50:50 mixtures caused a greater effect on overall mean growth indices than either sugar alone. Glucose content in twigs and starch in roots were significantly different (P < 0.05) among overall means for concentrations with increased levels found in trees treated with the greatest concentrations. Chlorophyll fluorescence Fv/Fm revealed highly significant differences (P < 0.001) among overall concentrations. Carbon isotope values did not reveal a definite trend that corroborated the exogenous carbohydrate distribution. Results from this experiment suggest that carbohydrate trunk injections can have an impact on growth and vitality of live oak.

Rapid influences of water stress on photosynthesis and translocation in Phaseolus vulgaris

1979 ◽  
Vol 57 (7) ◽  
pp. 768-776 ◽  
Author(s):  
John Hoddinott ◽  
D. L. Ehret ◽  
Paul R. Gorham
Keyword(s):  
Steady State ◽  
Phaseolus Vulgaris ◽  
Photosynthetic Rate ◽  
Osmotic Shock ◽  
Stomatal Closure ◽  
Transient Change ◽  
Before And After ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Labelling System

A steady-state 14C labelling system is used to simultaneously measure rates of photosynthesis and translocation before and after the onset of an osmotic shock to the base of rooted or rootless Phaseolus vulgaris plants. In all experiments, the photosynthetic rate declines soon after the onset of a shock owing to rapid stomatal closure. The translocation rate, following a brief transient change, remains almost constant for several hours, indicating less sensitivity to osmotic shock than is shown by the photosynthetic rate. The transient changes in translocation rate are due to transient changes in the leaf relative water content. The direction of the transient depends on the nature of the osmoticum and the presence or absence of roots.

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