Comparative Net Photosynthesis of Four Hevea brasiliensis Clonal Seedlings

1978 ◽  
Vol 14 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Zahar Samsuddin ◽  
Ivan Impens
Keyword(s):  
Hevea Brasiliensis ◽  
Light Response ◽  
Net Photosynthesis ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Light Response Curves ◽  
Single Leaf

SUMMARYSingle-leaf net photosynthesis versus light response curves of four Hevea brasiliensis clonal seedlings showed that it was possible to divide photosynthetic rates into high and low classes.

scholarly journals Photosynthetic Rate, Flowering, and Yield Component Alteration in Hazelnut in Response to Different Light Environments

1996 ◽  
Vol 121 (6) ◽  
pp. 1103-1111 ◽  
Author(s):  
Cheryl R. Hampson ◽  
Anita N. Azarenko ◽  
John R. Potter
Keyword(s):  
Photosynthetic Rate ◽  
Dark Respiration ◽  
Stomatal Density ◽  
Chlorophyll Concentration ◽  
Light Response ◽  
Dry Weight ◽  
Yield Component ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Light Response Curves

In hazelnut (Corylus avellana L.), vigorous vegetative growth and traditional orchard practices that include little or no pruning combine to produce a dense, shady canopy. A study designed to quantify the effect of shade on reproduction and photosynthetic rate in this shade-tolerant species was undertaken to assess whether some degree of pruning might improve productivity. Shade cloth was used to exclude 30%, 47%, 63%, 73%, or 92% of ambient sunlight from whole `Ennis' and `Barcelona' trees from mid-May until harvest. Photosynthetic light response curves were obtained for leaves that had developed in full sunlight, deep inside the canopy of unshaded trees, or in 92% shade. Light-saturated net photosynthetic rates were 12.0, 6.1, and 9.3 μmol·m-2·s-1 of CO2 and dark respiration rates were 2.0, 1.1, and 0.7 μmol·m-2·s-1 of CO2, respectively, for the three light regimes. Light-saturated photosynthetic rates of leaves from 30% or 63% shade differed little from the control (0% shade). Area per leaf increased by 49% and chlorophyll concentration (dry weight basis) by 157% as shading increased from 0% to 92%. Shading to 92% reduced specific leaf weight (68%), stomatal density (30%), light compensation point (69%), and dark respiration rate (63%) compared to controls. Female inflorescence density declined by about one-third and male inflorescence density by 64% to 74% in the most heavily shaded trees of both cultivars compared to controls. Shade was more detrimental to yield than flowering: yield per tree dropped by >80%, from 2.9 to 3.4 kg in full sun to 0.6 to 0.9 kg in 92% shade. Shade reduced yield primarily by decreasing nut number and secondarily by decreasing nut size. The incidence of several kernel defects increased as shade increased. Therefore, hazelnut leaves showed considerable capacity to adapt structurally and functionally to shade, but improving light penetration into the canopy would probably increase orchard productivity.

scholarly journals Canopy Position Affects Light Response Curves for Gas Exchange Characteristics of Apple Spur Leaves

1992 ◽  
Vol 117 (3) ◽  
pp. 467-472 ◽  
Author(s):  
Richard J. Campbell ◽  
Richard P. Marini ◽  
Jeffrey B. Birch
Keyword(s):  
Gas Exchange ◽  
Dark Respiration ◽  
Incident Light ◽  
Light Response ◽  
Net Photosynthesis ◽  
Response Curves ◽  
Light Response Curves ◽  
Light Levels ◽  
Canopy Position ◽  
Gas Exchange Characteristics

Light response curves for gas exchange characteristics were developed for spur leaves of `Stayman' and `Delicious' apple (Malus domestica Borkh.) from interior, intermediate, and exterior canopy positions throughout the season. At full bloom (FB), before full leaf expansion, exterior leaves had higher maximum rates of net photosynthesis (Pn), and a statistically different Pn light response curve than the interior leaves. Intermediate leaves had intermediate Pn rates and light response curves. Pn light response curves for all three `Delicious' canopy positions differed from each other from FB + 6 weeks until the end of the season. Interior leaves had maximum Pn rates of only 50% to 60% of those for the exterior leaves from FB + 10 weeks until the end of the season. Light saturation levels were higher for the exterior leaves than for interior or intermediate leaves. Exterior leaves had a tendency throughout the season for higher quantum efficiency of Pn at subsaturating light levels than interior or intermediate leaves. Stomatal conductance was higher for the exterior than the interior or intermediate leaves of `Delicious' on all dates. Water-use efficiency was equivalent among all leaves. Exterior leaves had higher specific leaf weight, dark respiration rates, and incident light levels on all dates than interior or intermediate leaves.

scholarly journals Net Carbon Exchange Rate of Fragaria Species, Synthetic Octoploids, and Derived Germplasm

2012 ◽  
Vol 137 (3) ◽  
pp. 202-209 ◽  
Author(s):  
Rebecca M. Harbut ◽  
J. Alan Sullivan ◽  
John T.A. Proctor ◽  
Harry J. Swartz
Keyword(s):  
Exchange Rate ◽  
Light Response ◽  
Research Station ◽  
Carbon Exchange ◽  
Light Conditions ◽  
Response Curves ◽  
Low Light ◽  
Light Response Curves ◽  
Single Leaf ◽  
Net Carbon Exchange

The net carbon exchange rate (NCER) of Fragaria species, synthetic octoploids [SO (interspecific hybrids)], F1 (SO × cultivar), and first outcross [OC1 (F1 × cultivar)] hybrids were evaluated in both field and greenhouse conditions. Plants were grown in a field trial at the Elora Research Station in Ontario, Canada, for one season and then plants were dug and moved into a greenhouse where the trial was repeated during the next season. Single leaf photosynthesis measurements and light response curves were generated at different stages of plant development. Photosynthetic capacity of the species was related to the ecological background of the species with sun-adapted species having higher rates compared with the shade-adapted species. The Fragaria species and introgressed hybrids (F1 and OC1) had significantly higher NCERs compared with the cultivars with rates 28% and 23% higher, respectively. Species and hybrids also appear to have increased adaptability to both high and low light conditions. These increases in NCER may be a heterotic effect because NCER of the hybrids were consistently higher compared with the midparent values and in some cases, they were higher than the high parent. These results suggest that the introgression of lower-ploidy Fragaria species into the cultivated strawberry (Fragaria ×ananassa) may lead to increased NCER and light adaptability.

scholarly journals Growth, Carbon Acquisition, and Source-Sink Relationships in `Titan' Red Raspberry

1994 ◽  
Vol 119 (6) ◽  
pp. 1163-1168 ◽  
Author(s):  
Gina E. Fernandez ◽  
Marvin P. Pritts
Keyword(s):  
Accumulation Rate ◽  
Light Response ◽  
Dry Weight ◽  
Rubus Idaeus ◽  
Field Conditions ◽  
Partial Recovery ◽  
Red Raspberry ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Light Response Curves

Seasonal changes in growth, mean maximal photosynthetic rates, and the temperature and light response curves of `Titan' red raspberry (Rubus idaeus L.) were obtained from potted plants grown under field conditions. Primocane dry weight accumulation increased steadily at the beginning and the end of the season, but growth slowed midseason during fruiting. The slower midseason dry-weight accumulation rate coincided with an increase in root dry weight. Primocane net assimilation rate (NAR) was highest early in the season. Floricane photosynthetic rates (A) were highest during the fruiting period, while primocane A remained steady throughout the season. Primocane and floricane leaflets displayed a midday depression in A under field conditions, with a partial recovery in the late afternoon. Photosynthetic rates of primocane and floricane leaves were very sensitive to temperature, exhibiting a decline from 15 to 40C. Light-response curves differed depending on cane type and time of year. A temporal convergence of sink demand from fruit, primocanes, and roots occurs when plants experience high temperatures. These factors may account for low red raspberry yield.

Physiological ecology of lodgepole pine (Pinuscontorta) in an enriched CO2 environment

1985 ◽  
Vol 15 (2) ◽  
pp. 417-421 ◽  
Author(s):  
K. O. Higginbotham ◽  
J. M. Mayo ◽  
S. L'Hirondelle ◽  
D. K. Krystofiak
Keyword(s):  
Surface Area ◽  
Leaf Surface ◽  
Lodgepole Pine ◽  
Stomatal Closure ◽  
Light Response ◽  
Net Photosynthesis ◽  
Response Curves ◽  
Light Response Curves ◽  
Leaf Surface Area ◽  
Photosynthetic Responses

Relatively little work has been done to evaluate the effects of chronically high levels of carbon dioxide on growth and physiology of woody plants. In this study, seedlings of lodgepole pine (Pinuscontorta Dougl. var. latifoliaEngelm.) were grown for 5-month periods at 330, 1000, or 2000 μL CO2•L−1. Height growth; leaf area production; biomass of leaves, stems, and roots; and photosynthetic responses to changing light, moisture, and CO2 concentration were measured. Significant differences between treatments were found in mean seedling height on all measurement dates. Seedlings grown at 1000 μL CO2•L−1 were tallest, with seedlings grown in 2000 μL•L−1 intermediate between the control (330 μL•L−1) and 1000 μL•L−1 treatments. The same relationship was found in production of total leaf surface area. Increased leaf surface area yields a productive advantage to seedlings grown at concentrations of CO2 up to 2000 μL•L−1 even if no increase in net photosynthesis is assumed. Biomass of stems, roots, and secondary leaves was increased in both elevated CO2 conditions, with root biomass approximately 15 times greater in seedlings grown at 1000 μL•L−1 than in those grown at 330 μL•CO2•L−1. Stomatal resistances were essentially the same for all treatments, indicating no CO2-induced stomatal closure to at least 2000 μL•L−1. Photosynthetic Vmax (milligrams per square decimetre per hour) for light response curves varied with CO2 concentration. If results are extrapolated beyond a 5-month period and into field conditions, it appears that size of trees, interactions with competitors, and ecological role of the species might be altered.

scholarly journals GROWTH, CARBON ACQUISITION, AND SOURCE-SINK RELATIONSHIPS IN `TITAN' RED RASPBERRY

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 248b-248 ◽  
Author(s):  
G. Fernandez ◽  
M. Pritts
Keyword(s):  
High Temperatures ◽  
Light Response ◽  
Dry Weight ◽  
Yield Component ◽  
Rubus Idaeus ◽  
Partial Recovery ◽  
Red Raspberry ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Light Response Curves

Seasonal changes in growth, photosynthetic rates, temperature, and light response curves of `Titan' red raspberry (Rubus idaeus L.) were obtained from potted plants grown under field conditions. Primocane dry weight accumulation underwent two phases of linear growth at the beginning and the end of the season, but growth slowed during fruiting. This slower rate of dry weight accumulation also coincided with an increase in root dry weight. Primocane NAR and SLA were highest early in the season. Light response curves differed depending on cane type and time of year. Floricane photosynthetic rates (A) were high during the fruiting period, while primocane A rates remained steady throughout the season. Both primocane and floricane leaflets displayed a midday drop in A rate, with a partial recovery in late afternoon. Photosynthetic rates of both primocane and floricane leaves were very sensitive to high temperatures. Temporal convergence of sink demand from fruit, primocanes, and roots occurs when plants experience high temperatures. This may account for low realized yields in raspberry and the high level of yield component compensation typical of source-limited plants.

The influence of the hemiparasitic angiosperm Cassytha pubescens on photosynthesis of its host Cytisus scoparius

2010 ◽  
Vol 37 (1) ◽  
pp. 14 ◽  
Author(s):  
Hao Shen ◽  
Jane N. Prider ◽  
José M. Facelli ◽  
Jennifer R. Watling
Keyword(s):  
Carbon Fixation ◽  
Stomatal Closure ◽  
Light Response ◽  
Poor Performance ◽  
Quantum Yields ◽  
Cytisus Scoparius ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Invasive Shrub ◽  
Light Response Curves

Infection with Cassytha pubescens R.Br, an Australian native hemiparasitic plant, can lead to death of the invasive shrub, Cytisus scoparius L. Link (Scotch broom). We examined the influence of C. pubescens on photosynthetic physiology of C. scoparius to determine whether this might contribute to death of infected plants. Infected C. scoparius had significantly lower photosynthetic rates, stomatal conductance and transpiration, and higher Ci (internal [CO2]), than uninfected plants. Rapid light response curves, determined using chlorophyll fluorescence, indicated significantly lower light-saturated electron transport rates and lower quantum yields for infected plants relative to uninfected plants. However, Rubisco content did not differ between infected and uninfected plants, suggesting the lower photosynthetic rates were most likely due to stomatal closure, rather than lower photosynthetic capacity. As a consequence of lower assimilation rates, PSII efficiency was lower in infected plants than uninfected plants across the diurnal cycle. Infected plants also had significantly lower pre-dawn Fv/Fm values and slower recovery from exposure to high light than uninfected plants. Our results suggest that infected C. scoparius are more susceptible to photodamage than uninfected plants. Combined with lower carbon fixation rates, this could contribute to the poor performance and even death of infected plants.

Photosynthetic light-response curves

Planta ◽  
1993 ◽  
Vol 189 (2) ◽  
Author(s):  
E. �gren ◽  
J.R. Evans
Keyword(s):  
Light Response ◽  
Response Curves ◽  
Light Response Curves
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