Photoperiod has a stronger impact than irradiance on the source–sink relationships in the sink-limited species Erythronium americanum

Botany ◽  
2011 ◽  
Vol 89 (11) ◽  
pp. 763-770 ◽  
Author(s):  
Anthony Gandin ◽  
Pierre Dizengremel ◽  
Line Lapointe
Keyword(s):  
Feedback Control ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Feedback Inhibition ◽  
Photochemical Efficiency ◽  
Biomass Accumulation ◽  
Growth Season ◽  
Erythronium Americanum ◽  
Source Sink ◽  
Long Photoperiod

Under sink-limited conditions, source activity is modulated to remain in balance with the use of carbohydrates by the sink, but this feedback control has been studied in only a few systems so far. Sink and source activities were investigated throughout the season. Plants were subjected to two photoperiod regimes combined with two irradiance levels to produce three different daily amounts of photons. Net photosynthetic rate and the photochemical efficiency of photosynthesis were initially higher under a long photoperiod, but decreased early in the growth season, whereas they remained fairly constant until a few days before leaf senescence under a short photoperiod. The rates of starch and biomass accumulation in the bulb were also faster under a long photoperiod at the beginning of the season but reached similar levels under both short and long photoperiods later on. Response to photoperiod cannot be explained by changes in daily amounts of photons, as none of the variables reported were affected by instantaneous or daily irradiance. It appears that the total amount of carbohydrate synthesized under a long photoperiod was in excess compared to the ability of the sink to store or use them, inducing a feedback inhibition of net photosynthetic rate to restore the source–sink balance.

scholarly journals Calcium Affects Growth and Physiological Indices of Panax quinquefolium L.

HortScience ◽  
2022 ◽  
Vol 57 (1) ◽  
pp. 112-117
Author(s):  
Zhenghai Zhang ◽  
Hai Sun ◽  
Cai Shao ◽  
Huixia Lei ◽  
Jiaqi Qian ◽  
...  
Keyword(s):  
Photosynthetic Rate ◽  
Stress Resistance ◽  
Photochemical Efficiency ◽  
Biomass Accumulation ◽  
American Ginseng ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Root Activity ◽  
Panax Quinquefolium ◽  
Malondialdehyde Content

Calcium (Ca) is necessary for plant growth and stress resistance, which are essential for the successful cultivation of Panax quinquefolium L. (American ginseng). However, information about the physiology of Ca nutrition in this species is limited. Therefore, the objective of this study was to determine the effect of Ca on the growth and physiological performance of American ginseng. Two-year-old American ginseng plants were supplemented with the following Ca concentrations [Ca2+] in a hydroponic system: 0, 160.17, 320.34, 640.68, and 961.02 mg⋅L−1. Measurements included growth biomass accumulation, chlorophyll (Chl) content and fluorescence, photosynthetic parameters, antioxidant enzyme activity, root activity, and malondialdehyde content. Biomass, stem height, leaf area, maximum photochemical efficiency, and superoxide dismutase activity peaked at [Ca2+] of 640.68 mg⋅L−1. Actual photochemical efficiency, minimum saturating irradiance, photosynthetic rate, catalase and peroxidase activities, and root activity reached their maximum at [Ca2+] of 320.34 mg⋅L−1. Stem diameter and regulated thermal energy dissipation increased with [Ca2+]. The sum of nonregulated heat dissipation and fluorescence emission and malondialdehyde content decreased to a minimum at [Ca2+] of 320.34 mg⋅L−1. The Chl content reached a maximum at [Ca2+] of 160.17 mg⋅L−1, but the Chl a/b ratio increased with [Ca2+]; the actual photochemical efficiency and photosynthetic rate reached their maximum level at Chl a/b ratios of 2.04 and [Ca2+] of 320.34 mg⋅L−1. Therefore, the optimal [Ca2+] for American ginseng growth was 320.34 mg⋅L−1. Furthermore, an appropriate increase [Ca2+] in the growth medium may improve biomass accumulation, light energy utilization efficiency, and stress resistance in American ginseng.

scholarly journals Evaluation of Photosynthetic Characters and Regulation Pattern of Photosynthesis Associated Gene in Two Mulberry Varieties

2021 ◽  
Vol 25 (04) ◽  
pp. 863-872
Author(s):  
Yong Li
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Metabolic Pathways ◽  
Carbon Fixation ◽  
Expression Patterns ◽  
Photochemical Efficiency ◽  
High Yield ◽  
Photochemical Quenching ◽  
Chlorophyll Metabolism ◽  
Photosynthetic Organisms

Photosynthetic characteristics and expression patterns of the photosynthesis-related genes in the high-yield mulberry variety E’Sang 1 (E1) and normal mulberry variety Husang 32 (H32) were investigated in this study. The observation of daily variation of photosynthesis in E1 and H32 indicated that the peak of net photosynthetic rate(Pn)inE1 variety was significantly higher than that inH32 (P <0.05). Meanwhile, the Pn-PAR and Pn-Ci responses of E1 and H32 were evaluated, and the results showed that the carboxylation efficiency and compensation saturation point were much higher in E1 rather thanH32. Importantly, the photosystem II actual photochemical efficiency and photochemical quenching coefficient in the leaves of E1 were significantly higher than those in H32 (P<0.05). Also, the activity of RuBP in E1 was higher than that in H32 (P >0.05). Based on the RNA-seq data, a total of 3,356 differentially expressed genes (DEGs) were detected among different time points between E1 and H32. Of these, 1,136 DEGs were involved in the metabolic pathways, including three main photosynthesis-related metabolic pathways (i.e., carbon fixation in photosynthetic organisms, carbon metabolism, and porphyrin and chlorophyll metabolism). Meanwhile, 10 novel DEGs related to photosynthesis were detected, and four potential key genes of them could account for the differences in net photosynthetic rate and yield betweenH32 and E1.This study could provide important insights into the molecular breeding of mulberry varieties with high photosynthetic efficiency and contribute to understanding the genetic mechanism of photosynthesis.© 2021 Friends Science Publishers

scholarly journals Physiological Advantages of Grafted Watermelon (Citrullus lanatus) Seedlings under Low-temperature Storage in Darkness

HortScience ◽  
2011 ◽  
Vol 46 (7) ◽  
pp. 993-996 ◽  
Author(s):  
Ming Ding ◽  
Beibei Bie ◽  
Wu Jiang ◽  
Qingqing Duan ◽  
Hongmei Du ◽  
...  
Keyword(s):  
Low Temperature ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Citrullus Lanatus ◽  
Soluble Sugar ◽  
Photochemical Efficiency ◽  
Chlorophyll Contents ◽  
Low Temperature Storage ◽  
Short Period ◽  
Temperature Storage

Low-temperature storage in darkness is usually used for preserving seedlings for a short period. To investigate whether grafted watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] seedlings are superior to non-grafted ones under low-temperature storage in darkness and to study their physiological differences during storage, watermelon (‘Zaojia 84-24’) scions were grafted to pumpkin (Cucurbita moschata Duch. ‘Zhuangshi’) rootstocks. Carbohydrate levels; chlorophyll and malondialdehyde contents; the activities of superoxide dismutase, catalase, and peroxidase; and photochemical efficiency were assayed during 6 days of storage at 15 °C in darkness. After that, seedlings were transplanted into an artificial climate chamber. The net photosynthetic rate and stomatal conductance (gS) were measured on the first and third days after transplanting. The results showed that the grafted watermelon seedlings had more soluble sugar and chlorophyll contents, higher activities of antioxidant enzymes, and less malondialdehyde content than the non-grafted ones after 6 days of storage. In addition, low-temperature storage in darkness damaged the photosystem II of non-grafted watermelon seedlings more than that of grafted ones. After transplanting, grafted seedlings had a higher net photosynthetic rate. The results suggest that grafted watermelon seedlings were more suitable for the low-temperature storage in darkness than the non-grafted ones.

scholarly journals End-product Inhibition of Photosynthesis in Prunus cerasus L. in Response to Whole-plant Source-Sink Manipulation

1995 ◽  
Vol 120 (4) ◽  
pp. 583-599 ◽  
Author(s):  
Desmond R. Layne ◽  
J.A. Flore
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Feedback Inhibition ◽  
Photochemical Efficiency ◽  
Sour Cherry ◽  
Product Inhibition ◽  
Prunus Cerasus ◽  
Soluble Carbohydrates ◽  
Regeneration Rate ◽  
Source Sink

The source-sink ratio of l-year-old, potted `Montmorency' sour cherry (Prunus cerasus) trees was manipulated by partial defoliation (D) or continuous lighting (CL) to investigate the phenomenon of end-product inhibition of photosynthesis. Within 24 hours of D, net CO2 assimilation rate (A) of the most recently expanded source leaves of D plants was significantly higher than nondefoliated (control) plants throughout the diurnal photoperiod. Between 2 and 7 days after D, A was 30% to 50% higher and stomatal conductance rate (g,) was 50% to 100% higher than in controls. Estimated carboxylation efficiency(k) and ribulose-1,5-bisphosphate (RuBP) regeneration rate increased significantly within 2 days and remained consistently higher for up to 9 days after D. Leaf starch concentration and dark respiration rate decreased but sorbitol and sucrose concentration increased after D. The diurnal decline in A in the afternoon after D may have been due to feedback inhibition from accumulation of soluble carbohydrates (sucrose and sorbitol) in the cytosol. This diurnal decline indicated that trees were sink limited. By 9 days after D, photochemical efficiency was significantly higher than in control plants. In the long term, leaf senescence was delayed as indicated by higher A and gs in combination with higher chlorophyll content up to 32 days after D. CL resulted in a significant reduction of A, gs, k, variable chlorophyll fluorescence (Fv), photochemical efficiency, and estimated RuBP regeneration rate of the most recently expanded source leaves within 1 day. During the exposure to CL, A was reduced 2- to 3-fold and k was reduced up to 4-fold. The normal linear relationship between A and gs was uncoupled under CL indicating that A was not primarily limited by gs and since internal CO2 concentration was not significantly affected, the physical limitation to A imposed by the stomata was negligible. The decrease in Fv and photochemical efficiency indicated that leaves were photoinhibited within 1 day. The decrease in instantaneous chlorophyll fluorescence after at least 1 day of CL indicated that there was a reversible regulatory mechanism whereby the damage to photosystem II reaction centers was repaired. Leaf chlorophyll content was not altered by 1,2, or 3 days of exposure to CL, indicating that photooxidation of chlorophytl did not occur. The time to full photosynthetic recovery from CL increased as the duration of exposure increased. CL plants that were photoinhibited accumulated significant starch in the chloroplast in a companion study (Layne and Flore, 1993) and it is possible that an orthophosphate limitation in the chloroplast stroma was occurring. D plants that were continuously illuminated were not photosynthetically inhibited. After 7 days of CL, plants that were then partially defoliated yet remained in CL photosynthetically recovered within 5 days to pre-CL values. Under the conditions of this investigation, end-product inhibition of A occurred in young, potted sour cherry trees but the mechanism of action in D plants was different than in CL plants.

scholarly journals Photosynthesis, Chlorophyll Fluorescence, and Yield of Peanut in Response to Biochar Application

2021 ◽  
Vol 12 ◽  
Author(s):  
Shujun Wang ◽  
Junlin Zheng ◽  
Yujia Wang ◽  
Qingfeng Yang ◽  
Taotao Chen ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Leaf Gas Exchange ◽  
Photochemical Efficiency ◽  
Photochemical Quenching ◽  
Nitrogen Accumulation ◽  
Leaf Nitrogen Content ◽  
Chlorophyll Fluorescence Parameters ◽  
Plant Nitrogen

The effect of biochar application on photosynthetic traits and yield in peanut (Arachis hypogaea L.) is not well understood. A 2-year field experiment was conducted in Northwest Liaoning, China to evaluate the effect of biochar application [0, 10, 20, and 40 t ha−1 (B0, B10, B20, and B40)] on leaf gas exchange parameters, chlorophyll fluorescence parameters, and yield of peanut. B10 improved photochemical quenching at flowering and pod set and reduced non-photochemical quenching at pod set, relative to B0. B10 and B20 increased actual photochemical efficiency and decreased regulated energy dissipated at pod set, relative to B0. B10 significantly increased net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency at flowering and pod set, relative to B0. Compared with B0, B10 significantly improved peanut yield (14.6 and 13.7%) and kernel yield (20.2 and 14.4%). Biochar application increased leaf nitrogen content. B10 and B20 significantly increased plant nitrogen accumulation, as compared to B0. The net photosynthetic rate of peanut leaves had a linear correlation with plant nitrogen accumulation and peanut yield. The application of 10 t ha−1 biochar produced the highest peanut yield by enhancing leaf photosynthetic capacity, and is thus a promising strategy for peanut production in Northwest Liaoning, China.

scholarly journals Shading Reduces Water Deficit in Strawberry (Fragaria × ananassa Duch.) Plants during Vegetative Growth

2021 ◽  
Author(s):  
Henry A. Cordoba-Novoa ◽  
María Mercedez Pérez Trujillo ◽  
Brahyam Emmanuel Cruz Rincon ◽  
Nixon Florez Velazco ◽  
Stanislav Magnitskiy ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Light Intensity ◽  
Water Potential ◽  
Net Photosynthetic Rate ◽  
Water Deficit ◽  
Photosynthetic Rate ◽  
Vegetative Growth ◽  
Incident Light ◽  
Photochemical Efficiency ◽  
Photosystem Ii Efficiency

Strawberry (Fragaria × ananassa Duch.) is a commercially important crop with high water requirements, for which it is necessary to find strategies that mitigate the influence of water deficit on plant growth. This study was aimed to evaluate the effects of shading on the vegetative growth of strawberry cv. Sweet Ann under water deficit. The treatments consisted of the combination of two levels of shading (light intensity reduced on 47% vs. non-shaded plants) and two levels of water availability (water deficit vs. well-watered plants). The water deficit reduced the leaf water potential from -1.52 to -2.21 MPa, and diminished stomatal conductance, net photosynthetic rate (from 9.13 to 2.5 μmol m-2 s-1), photosystem II photochemical efficiency (from 0.79 to 0.67), and biomass accumulation, while increased the electrolyte leakage. The shading allowed the water-deficient plants to maintain water potential (-1.58 MPa) and photosystem II efficiency (0.79) and to increase water use efficiency (from 14.80 to 86.90 μmol CO2/mmol H2O), net photosynthetic rate (from 2.40 to 9.40 μmol m-2 s-1) and biomass of leaves, crowns, and roots compared to non-shaded plants without water limitation. These results suggest that a reduction in incident light intensity attenuates the effects of stomatic and non-stomatic limitations caused by water deficit during vegetative growth of strawberry.

scholarly journals Morphological and Physiological Responses of Morus alba Seedlings under Different Light Qualities

2016 ◽  
Vol 44 (2) ◽  
pp. 382-392 ◽  
Author(s):  
Juwei HU ◽  
Xin DAI ◽  
Guangyu SUN
Keyword(s):  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Photochemical Efficiency ◽  
Morus Alba ◽  
Leaf Thickness ◽  
Stem Length ◽  
Leaf Mass Per Area ◽  
Palisade Tissue

Light quality can influence the photosynthetic characteristics, morphology and physiological processes of plants. To investigate the effects of different light qualities (white light, W; red light, R; blue light, B; mixture of red and blue light, RB) of light emitting diodes (LEDs) and white cold fluorescent lamp on the growth and morphology of fruiting mulberry plants (Morus alba L. cv. ‘Longsang No.1’), fruiting mulberry plants were grown under different light qualities: W, R, B and RB of the same photosynthetic photo flux density (PPFD; 100 μmol m-2 s-1) for 20 d. Our results showed that stem length and leaf area of plants grown under R were the highest. However, stem length and leaf area of plants grown under B were lowest. Dry weights (DW), leaf mass per area (LMA), chlorophyll a/b ratio, soluble protein content, sucrose and starch content, and total leaf nitrogen (N) content of plants grown under R were the lowest. Net photosynthetic rate (Pn), stomatal conductance (gs), and actual photochemical efficiency of PSII (ΦPSII) of plants grown under RB were similar to plants grown under W. Net photosynthetic rate (Pn) and ΦPSII of plants grown under R and B were lower than plants grown under W and RB. Antioxidant enzymes activity of plants grown under R, RB and B were higher than plants grown under W. The number of leaf stomata, leaf thickness, palisade tissue length and spongy tissue length were the lowest in plants grown under R. The number of leaf stomata, leaf thickness and palisade tissue length of plants grown under RB and B were higher than plants grown under R. The results of this study indicate that a certain ratio of mixed red and blue LEDs light can reduce adverse effects of monochromatic red and blue LEDs light on fruiting mulberry growth and development.

Diurnal variation in net photosynthetic rate and influencing environmentalfactors of Elaeagnus mollis Diels leaf

2009 ◽  
Vol 17 (3) ◽  
pp. 474-478
Author(s):  
Qun-Long LIU ◽  
Chan-Juan NING ◽  
Duo WANG ◽  
Guo-Liang WU ◽  
Hong-Mei ZHANG ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Elaeagnus Mollis
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