The photosynthetic response of American chestnut seedlings to differing light conditions

2007 ◽  
Vol 37 (9) ◽  
pp. 1714-1722 ◽  
Author(s):  
Heather M. Joesting ◽  
Brian C. McCarthy ◽  
Kim J. Brown
Keyword(s):  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Nitrogen Concentration ◽  
American Chestnut ◽  
Control Treatment ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Light Conditions ◽  
Eastern Deciduous Forest

Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.

scholarly journals Leaf Photosynthetic Capacity of Sunlit and Shaded Mature Leaves in a Deciduous Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 318
Author(s):  
Guangman Song ◽  
Quan Wang ◽  
Jia Jin
Keyword(s):  
Close Relationships ◽  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Leaf Traits ◽  
Leaf Nitrogen ◽  
Leaf Mass Per Area ◽  
Clear Understanding ◽  
Equivalent Water Thickness

A clear understanding of the dynamics of photosynthetic capacity is crucial for accurate modeling of ecosystem carbon uptake. However, such dynamical information is hardly available and has dramatically impeded our understanding of carbon cycles. Although tremendous efforts have been made in coupling the dynamic information of photosynthetic capacity into models, using “proxies” rooted from the close relationships between photosynthetic capacity and other available leaf parameters remains the popular selection. Unfortunately, no consensus has yet been reached on such “proxies”, leading them only applicable to limited cases. In this study, we aim to identify if there are close relationships between the photosynthetic capacity (represented by the maximum carboxylation rate, Vcmax) and leaf traits for mature broadleaves within a cold temperature deciduous forest. This is based on a long-term in situ dataset including leaf chlorophyll content (Chl), leaf nitrogen concentration (Narea, Nmass), leaf carbon concentration (Carea, Cmass), equivalent water thickness (EWT), leaf mass per area (LMA), and leaf gas exchange measurements from which Vcmax was derived, for both sunlit and shaded leaves during leaf mature periods from 2014 to 2019. The results show that the Vcmax values of sunlit and shaded leaves were relatively stable during these periods, and no statistically significant interannual variations occurred (p > 0.05). However, this is not applicable to specific species. Path analysis revealed that Narea was the major contributor to Vcmax for sunlit leaves (0.502), while LMA had the greatest direct relationship with Vcmax for shaded leaves (0.625). The LMA has further been confirmed as a primary proxy if no leaf type information is available. These findings provide a promising way to better understand photosynthesis and to predict carbon and water cycles in temperate deciduous forests.

scholarly journals Drought stress imposes reversible photosynthetic damage under fluctuating light conditions in crops

2021 ◽  
Author(s):  
Kazuma Sakoda ◽  
Kazuki Taniyoshi ◽  
Wataru Yamori ◽  
Yu Tanaka
Keyword(s):  
Drought Stress ◽  
Photosynthetic Capacity ◽  
Crop Growth ◽  
Growth And Yield ◽  
Carbon Gain ◽  
Limiting Factor ◽  
Photosynthetic Induction ◽  
Light Conditions ◽  
Fluctuating Light ◽  
Dynamic Photosynthesis

Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions by conducting gas exchange measurements in two major crops, namely rice and soybean. In both crops, drought stress reduced steady-state photosynthesis and/or photosynthetic capacity, and delayed photosynthetic induction even when it had relatively small impact on photosynthetic capacity, suggesting that the drought effects on photosynthesis should be evaluated based on induction, maximum, and steady states. This delayed photosynthetic induction resulted in a substantial loss of carbon gain under fluctuating light conditions, which can be a limiting factor for crop growth and yield in the field. Meanwhile, rewatering after drought conditions completely recovered photosynthetic capacity and induction in both crops, whereas drought experience would be memorized to slow down the stomatal opening. Therefore, the stability of photosynthetic induction can be a promising target to improve drought tolerance during crop breeding in the future.

scholarly journals Seasonal courses of photosynthetic parameters in sun- and shade-acclimated spruce shoots

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 49-56 ◽  
Author(s):  
Otmar Urban ◽  
Petr Holub ◽  
Karel Klem
Keyword(s):  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Carbon Assimilation ◽  
Growing Season ◽  
Early Spring ◽  
Total Carbon ◽  
Carbon Gain ◽  
Carbon Uptake ◽  
Photosynthetic Parameters ◽  
Sun And Shade

Exponential attenuation of light intensity passing through forest canopies leads to the formation of sun- and shade-acclimated leaves contributing to overall canopy carbon gain. Using a gas-exchange technique, seasonal changes in photosynthetic parameters were investigated in situ to test the hypothesis that the relative contributions of sun- and shade-acclimated Norway spruce shoots to total carbon gain vary during the growing season and that the contribution of sun-acclimated shoots to total carbon uptake may be reduced during the hot and dry summer season. In agreement with the tested hypothesis, we found reduced photosynthetic capacity as well as reduced light-use efficiency for carbon assimilation in sun-acclimated shoots during summer months while these remained almost unchanged in shade-acclimated shoots. Reduction of photosynthetic capacity was primarily associated with reduced stomatal conductance. On the other hand, seasonal courses of mitochondrial dark respiration, quantum efficiency of photosynthetic reactions, and compensation irradiance were primarily driven by changes in temperature. Accordingly, the photosynthetic characteristics of sun- and shade-acclimated shoots tended to converge in early spring and late autumn when temperature was low. Such seasonal dynamics result in an increased contribution of shade-acclimated shoots to total carbon uptake at the beginning and end of the growing season as well as during hot and dry summer periods.

Lichen carbon gain under tropical conditions: water relations and CO2 exchange of Lobariaceae species of a lower montane rainforest in Panama

2004 ◽  
Vol 36 (5) ◽  
pp. 329-342 ◽  
Author(s):  
Otto L. LANGE ◽  
Burkhard BÜDEL ◽  
Angelika MEYER ◽  
Hans ZELLNER ◽  
Gerhard ZOTZ
Keyword(s):  
Water Relations ◽  
Carbon Fixation ◽  
Nitrogen Concentration ◽  
Carbon Gain ◽  
Carbon Loss ◽  
Natural Conditions ◽  
Low Light ◽  
Green Algal ◽  
Tropical Conditions ◽  
Montane Rainforest

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

THE DISTRIBUTION OF DERMACENTOR TICKS IN CANADA IN RELATION TO BIOCLIMATIC ZONES

1967 ◽  
Vol 45 (4) ◽  
pp. 517-537 ◽  
Author(s):  
P. R. Wilkinson
Keyword(s):  
British Columbia ◽  
Deciduous Forest ◽  
Strong Association ◽  
Eastern Deciduous Forest ◽  
Egg Development ◽  
The North ◽  
Winter Activity ◽  
Bioclimatic Zone ◽  
Soil Temperatures ◽  
Time Of Year

Dermacentor andersoni has been collected north of Jasper, Alberta, close to 54° N. and near 53° N. in British Columbia. Spread to the north and northwest is probably limited by low summer soil temperatures, which would act principally by slowing egg development, thus disrupting the seasonal cycle of the tick. To the southwest, mild winters may fail to release diapause at the correct time of year. Aspect and slope are important factors. Altitude spread of records is from 1000–7000 ft. The most generally applicable description of its distribution is the ecotone between western grassland and moister regions, including clearings and rocky outcrops m the montane and Columbia forests, and shrubby areas of the prairies. In British Columbia, a series of randomly selected transects indicated a strong association between the tick's presence and several species of shrubs growing without tree shade.Each bioclimatic zone tends to have a characteristic group of rodents as main hosts of the immature stages. The prairie and montane regions differ in the indigenous hosts available to the adult tick.East of 105° D. andersoni is replaced by D. variabilis, which is adapted to the more humid summers of the eastern deciduous forest zones, and differs considerably from D. andersoni in its phenology. There are no reliable records of indigenous D. variabilis north of 52° latitude.D. albipictus occurs from the east to the west coast. Because of the winter activity of its larvae, allowing the whole summer for egg development, it is able to penetrate much farther north than the other two species. There are two records close to 60° latitude.

scholarly journals Effects of seasonal variation of photosynthetic capacity on the carbon fluxes of a temperate deciduous forest

2013 ◽  
Vol 118 (4) ◽  
pp. 1703-1714 ◽  
Author(s):  
David Medvigy ◽  
Su-Jong Jeong ◽  
Kenneth L. Clark ◽  
Nicholas S. Skowronski ◽  
Karina V. R. Schäfer
Keyword(s):  
Seasonal Variation ◽  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Carbon Fluxes ◽  
Temperate Deciduous Forest ◽  
Temperate Deciduous

The biology of Canadian weeds. 130. Solidago nemoralis Ait.

2004 ◽  
Vol 84 (4) ◽  
pp. 1221-1233 ◽  
Author(s):  
Jerry G. Chmielewski ◽  
John C. Semple
Keyword(s):  
United States ◽  
North America ◽  
Deciduous Forest ◽  
Sandy Soils ◽  
The United States ◽  
Eastern Deciduous Forest ◽  
Rock Outcrops ◽  
Native North American ◽  
Forest Region ◽  
Riparian Habitats

Solidago nemoralis, the gray goldenrod, is a polycarpic hemicryptophyte that reproduces vegetatively from branched caudices. This native North American species is morphologically variable throughout its range, and includes an eastern (ssp. nemoralis) and western (ssp. decemflora) race. The eastern subspecies occurs throughout the eastern deciduous forest region of North America and is commonly diploid, though tetraploids do occur throughout. The western race typically occurs on the prairies and is strictly tetraploid. The species occupies riparian habitats, rock outcrops and open fields and roadsides and grows best in well-drained sandy soils in full sunlight. Although the species is weedy in both Canada and the United States it is not noxious. Key words: Solidago nemoralis, gray goldenrod, verge d'or des bois, Asteraceae, Compositae

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