scholarly journals Effects of Elevated CO2 on Leaf Senescence, Leaf Nitrogen Resorption, and Late-Season Photosynthesis in Tilia americana L.

2019 ◽  
Vol 10 ◽  
Author(s):  
Li Li ◽  
Xiaoke Wang ◽  
William J. Manning
Keyword(s):  
Elevated Co2 ◽  
Leaf Senescence ◽  
Leaf Nitrogen ◽  
Late Season ◽  
Nitrogen Resorption

scholarly journals Elevated CO2 Increases Root Mass and Leaf Nitrogen Resorption in Red Maple (Acer rubrum L.)

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 420 ◽  
Author(s):  
Li Li ◽  
William Manning ◽  
Xiaoke Wang
Keyword(s):  
Elevated Co2 ◽  
Biomass Allocation ◽  
Acer Rubrum ◽  
Leaf Nitrogen ◽  
Leaf Mass Per Area ◽  
Continuous Stirred Tank Reactor ◽  
Red Maple ◽  
Resorption Efficiency ◽  
Nitrogen Resorption ◽  
Leaf N

To understand whether the process of seasonal nitrogen resorption and biomass allocation are different in CO2-enriched plants, seedlings of red maple (Acer rubrum L.) were exposed to three CO2 concentrations (800 µL L−1 CO2 treatments—A800, 600 µL L−1 CO2 treatments—A600, and 400 µL L−1 CO2 treatments—A400) in nine continuous stirred tank reactor (CSTR) chambers. Leaf mass per area, leaf area, chlorophyll index, carbon (C), nitrogen (N) contents, nitrogen resorption efficiency (NRE), and biomass allocation response were investigated. The results indicated that: (1) Significant leaf N decline was found in senescent leaves of two CO2 treatments, which led to an increase of 43.4% and 39.7% of the C/N ratio in A800 and A600, respectively. (2) Elevated CO2 induced higher NRE, with A800 and A600 showing significant increments of 50.3% and 46.2%, respectively. (3) Root biomass increased 33.1% in A800 and thus the ratio of root to shoot ratio was increased by 25.8%. In conclusion, these results showed that to support greater nutrient and water uptake and the continued response of biomass under elevated CO2, Acer rubrum partitioned more biomass to root and increased leaf N resorption efficiency.

The Role of Eco-Friendly Soil Amendments Co-Application on the Performance of Lingrain (Linum Usitatissimum L.) Under Late-Season Irrigation Limitation

2020 ◽  
Author(s):  
Mahdieh Fallah ◽  
Reza Amirnia ◽  
Hashem Hadi ◽  
Abdollah Hassanzadeh-Ghorttapeh
Keyword(s):  
Green Manure ◽  
Trifolium Pratense ◽  
Synergistic Effects ◽  
Soil Amendments ◽  
Leaf Nitrogen ◽  
Plant Performance ◽  
Water Limitation ◽  
Late Season ◽  
Single Use

Abstract This study's main purpose was to investigate the probable amelioration of limited irrigation conditions by soil amendments for lingrain plants. The experiment was accomplished as a completely randomized factorial design along with three replications. The first factor was green manure (without (Gc) and with Trifolium pratense (Gr)), the second factor consisted of Rhizophagus irregularis mycorrhiza (Fm), vermicompost (Fv), both of mycorrhiza and vermicompost (Fm+v) and none of them (Fc), and also the third factor was irrigation regime (full irrigation and late-season water limitation). Green manure, vermicompost and mycorrhiza single-use enhanced the plant performance under water limitation conditions in comparison with the control. However, in the presence of vermicompost, along with green manure or mycorrhiza developed a positive synergistic effect on most of the traits. Combining green manure with the dual fertilizer (Fm+v) resulted in the vermicompost and mycorrhiza synergistic effects, especially under limited irrigation. Consequently, the triple fertilizer (Gr×Fm+v) experienced the highest amount of LRWC, root colonization, leaf nitrogen, chlorophyll a, chlorophyll b, carotenoids, antioxidant enzymes activity, grain yield and oil yield, which would lead to more resistance of plants to limited irrigation conditions.

The Optimal Allocation of Nitrogen Within the C3 Photosynthetic System at Elevated CO2

1996 ◽  
Vol 23 (5) ◽  
pp. 593 ◽  
Author(s):  
BE Medlyn
Keyword(s):  
Elevated Co2 ◽  
Optimal Allocation ◽  
Co2 Concentration ◽  
Leaf Nitrogen ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Nitrogen Distribution ◽  
Photosynthetic System ◽  
Light Regimes ◽  
Nitrogen Contents

The distribution of nitrogen among compounds involved in photosynthesis varies in response to changes in environmental conditions such as photon flux density. However, the extent to which the nitrogen distribution within leaves adjusts in response to increased atmospheric CO2 is unclear. A model was used to determine the nitrogen distribution which maximises photosynthesis under realistic light regimes at both current and elevated levels of CO2, and a comparison was made with observed leaf nitrogen distributions reported in the literature. The model accurately predicted the distribution of nitrogen within the photosynthetic system for leaves grown at current levels of CO2, except at very high leaf nitrogen contents. The model predicted that, under a doubling of CO2 concentration from its current level, the ratio of electron transport capacity to Rubisco activity (Jmax : Vcmax) should increase by 40%. In contrast, measurements of Jmax : Vcmax taken from the literature show a slight but non-significant increase in response to an increase in CO2. The discrepancy between predicted and observed Jmax : Vcmax suggests that leaf nitrogen distribution does not acclimate optimally to elevated CO2. Alternatively, the discrepancy may be due to effects of CO2 which the model fails to take into account, such as a possible decrease in the conductance to CO2 transfer between the intercellular spaces and the sites of carboxylation at elevated CO2.

Nitrogen resorption and protein degradation during leaf senescence in Chenopodium album grown in different light and nitrogen conditions

2007 ◽  
Vol 34 (5) ◽  
pp. 409 ◽  
Author(s):  
Yuko Yasumura ◽  
Kouki Hikosaka ◽  
Tadaki Hirose
Keyword(s):  
Protein Degradation ◽  
Leaf Senescence ◽  
Chenopodium Album ◽  
Growth Conditions ◽  
Sink Strength ◽  
Physiological Factors ◽  
Nitrogen Resorption ◽  
Protein Pool ◽  
N Resorption ◽  
Leaf N

The extent of nitrogen (N) resorption and the degradability of different protein pools were examined in senescing leaves of an annual herb, Chenopodium album L., grown in two light and N conditions. Both N resorption efficiency (REFF; the proportion of green-leaf N resorbed) and proficiency (RPROF; the level to which leaf N content is reduced by resorption) varied among different growth conditions. During leaf senescence, the majority of soluble and membrane proteins was degraded in all growth conditions. Structural proteins were also highly degradable, implying that no particular protein pool constitutes a non-retranslocatable N pool in the leaf. Leaf carbon/N ratio affected the timing and duration of senescing processes, but it did not regulate the extent of protein degradation or N resorption. Sink–source relationships for N in the plant exerted a more direct influence, depressing N resorption when N sink strength was weakened in the low-light and high-N condition. N resorption was, however, not enhanced in high-light and low-N plants with the strongest N sinks, possibly because it reached an upper limit at some point. We conclude that a combination of several physiological factors determines the extent of N resorption in different growth conditions.

scholarly journals Elevated CO2 enhances leaf senescence during extreme drought in a temperate forest

2011 ◽  
Vol 31 (2) ◽  
pp. 117-130 ◽  
Author(s):  
J. M. Warren ◽  
R. J. Norby ◽  
S. D. Wullschleger
Keyword(s):  
Elevated Co2 ◽  
Leaf Senescence ◽  
Temperate Forest ◽  
Extreme Drought
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