Photosynthetic rates in relation to nitrogen recycling as an adaptation to nutrient deficiency in peat bog plants

1972 ◽  
Vol 50 (11) ◽  
pp. 2227-2233 ◽  
Author(s):  
Ernest Small

Fifteen species growing in a raised sphagnum peat bog were compared with 13 non-bog species with respect to their light-saturated net photosynthetic rate, and the content of N, P, and K within their foliage and leaf litter. Bog species were found to reabsorb significantly more nitrogen from their foliage preceding leaf fall than non-bog species. An estimate of the potential photosynthate which the species could manufacture during the time a given unit of nitrogen remained in the plant, before being lost through leaf fall, was calculated for the 28 species. The values found averaged 235% higher for the bog evergreens than for the bog deciduous species, and about 60% higher in the bog deciduous species than in the non-bog deciduous species. The hypothesis is advanced that the increased time available to use nitrogen photosynthetically before it is recycled is adaptive in bog plants, especially in evergreens, because of the difficulty in acquiring nitrogen from the extremely nutrient-deficient bog substrate.

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 127-130 ◽  
Author(s):  
David T. Patterson

The response of net photosynthetic rate to temperature and light, the rate of photorespiration, the compensation concentration for CO2, and the pathway of CO2fixation in smooth pigweed (Amaranthus hybridusL.) were investigated using infrared gas analysis and14CO2. Maximum net photosynthetic rates of whole shoots were 45 mg CO2dm-2hr-1at 30 C and 7.8 klux. Intact whole shoots were not light saturated at 10 klux. The optimum temperature for net photosynthesis was between 30 C and 40 C. Photorespiration was low and the CO2compensation concentration was 7 ppm. After a 5-sec exposure to14CO2in the light, label was detected in oxaloacetate, malate, and aspartate. It was concluded that smooth pigweed has the gross photosynthetic characteristics and CO2fixation pathway typical of C4or Hatch-Slack plants.


1984 ◽  
Vol 14 (6) ◽  
pp. 924-932 ◽  
Author(s):  
Neil D. Nelson ◽  
Paul Ehlers

Light-saturated net photosynthetic rates per unit leaf area were 1.6–2.1 times greater for the photosynthetically mature leaves of plants of two hybrid Populus clones (NC-5260, 'Tristis No.1' (Populustristis Fisch. × P. balsamifera L.); NC-5326, 'eugenei' (P. deltoides Bartr. ex Marsh. × P. nigra L.)) grown in pots in the field than in comparable plants from a controlled environment growth room and a winter greenhouse. Stomatal resistances to CO2 in the field trees were only 0.4–0.6 of those in growth room and greenhouse trees. Mesophyll (residual) resistances to CO2 in field trees were 0.4–0.8 of those in growth room and greenhouse trees. Field plants had specific leaf weights 1.5–1.8 times higher than growth room and greenhouse plants, likely primarily owing to the greater average photosynthetic photon flux density in the field (835, 225, and 142 μE m−2 s−1 for field, growth room, and greenhouse conditions, respectively). When net photosynthetic rates (Ps) were corrected for the differences in specific leaf weights to derive net photosynthetic rate per unit leaf dry weight, the values were similar for plants from the three environments (Ps in field trees was 0.9–1.2 times Ps in growth room and greenhouse trees); gross photosynthetic rates per unit leaf weight were even more similar. Internal leaf CO2 concentrations, and photorespiration and dark respiration rates per unit leaf area were not related to growth environment. However, photorespiration rate as a percentage of net photosynthetic rate was lower in the field trees (12–16% in field trees, 19–24% in growth room trees, and 23–39% in greenhouse trees). Net photosynthetic rate was shown to be under strong genetic control in these clones. The effects of growth environment on variables of carbon exchange are sensitive to the basis of expression of those variables.


2012 ◽  
Vol 518-523 ◽  
pp. 5423-5428 ◽  
Author(s):  
Chung Yi Chung ◽  
Pei Ling Chung ◽  
Hwa Sheng Gau ◽  
Shao Wei Liao ◽  
Wen Liang Lai ◽  
...  

Italic textThis research utilized a custom-made air fumigation equipment to evaluate the tolerance of 10 species of side-walk trees with 600, 1000 and 2000 ppb Sulfur Dioxide (SO2) for 48 hours. The tolerance of tested trees toward SO2pollution was analyzed. Results showed that these plants influenced by high concentration SO2gas with physiology properties changes and the decrease of photosynthetic rates and the stomata conductance than before fumigation. The net photosynthetic rate and stomata conductance of tested trees was linearly correlated to each tested tree species. Among tested tree, the Quercus glauca had the highest tolerance in exposure with high concentration of SO2pollutant. While the Camellia axillaries was the least.


2009 ◽  
Vol 17 (3) ◽  
pp. 474-478
Author(s):  
Qun-Long LIU ◽  
Chan-Juan NING ◽  
Duo WANG ◽  
Guo-Liang WU ◽  
Hong-Mei ZHANG ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yinli Bi ◽  
Huili Zhou

AbstractA well-developed canopy structure can increase the biomass accumulation and yield of crops. Peanut seeds were sown in a soil inoculated with an arbuscular mycorrhizal fungus (AMF) and uninoculated controls were also sown. Canopy structure was monitored using a 3-D laser scanner and photosynthetic characteristics with an LI-6400 XT photosynthesis system after 30, 45 and 70 days of growth to explore the effects of the AMF on growth, canopy structure and photosynthetic characteristics and yield. The AMF colonized the roots and AMF inoculation significantly increased the height, canopy width and total leaf area of the host plants and improved canopy structure. AMF reduced the tiller angle of the upper and middle canopy layers, increased that of the lower layer, reduced the leaf inclination of the upper, middle and lower layers, and increased the average leaf area and leaf area index after 45 days of growth, producing a well-developed and hierarchical canopy. Moreover, AMF inoculation increased the net photosynthetic rate in the upper, middle and lower layers. Plant height, canopy width, and total leaf area were positively correlated with net photosynthetic rate, and the inclination angle and tiller angle of the upper leaves were negatively correlated with net photosynthetic rate. Overall, the results demonstrate the effects of AMF inoculation on plant canopy structure and net photosynthetic rate.


Plant Science ◽  
2005 ◽  
Vol 169 (3) ◽  
pp. 523-531 ◽  
Author(s):  
K. Mosaleeyanon ◽  
S.M.A. Zobayed ◽  
F. Afreen ◽  
T. Kozai

1994 ◽  
Vol 30 (1) ◽  
pp. 1-16 ◽  
Author(s):  
B. Gail Smith ◽  
Paul J. Burgess ◽  
M. K. V. Carr

SummaryStomatal conductances (g) and photosynthetic rates (A) were monitored in six tea clones planted in a clone X irrigation experiment in the Southern Highlands of Tanzania. Measurements were made during the warm dry seasons of 1989 and 1990. There was no genotype X treatment interaction in the response in A or g of the various clones to irrigation. Irrigation increased A more than it increased g. Irrigation also increased the temperature optimum for photosynthesis and decreased photo-inhibition at high illuminance. Clones differed in g and A, and in the relationship between leaf temperature and A. The implications of these findings for clone selection are discussed.


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