The Effect of KHCO3 on Photosynthesis of Eggplant Seedlings

2013 ◽  
Vol 634-638 ◽  
pp. 1129-1134 ◽  
Author(s):  
Ying Chang Li ◽  
Jian Jun Hao
Keyword(s):  
Stomatal Conductance ◽  
Photosynthetic Rate ◽  
Impact Factors ◽  
C3 Plants ◽  
Transport Activity ◽  
Saturation Point ◽  
Rubisco Activity ◽  
Bisphosphate Carboxylase ◽  
Electron Transport Activity ◽  
Light Saturation Point

The low concentration of CO2 in the atmosphere is one of the main factors to restrict photosynthesis of C3 plants. The effect of KHCO3 on photosynthesis of eggplant seedlings was studied in order to improve photosynthesis of C3 plants. The results showed that KHCO3 could significantly enhance the photosynthetic rate of eggplant seedlings. 500mg/L KHCO3 was the most optimal concentration to improve photosynthetic rate of eggplant seedlings. KHCO3 could increase light saturation point, CO2 saturation point, carboxylase efficiency and lower CO2 compensate point of eggplant seedlings. KHCO3 could improve stomatal conductance and electron transport activity. There was phosphoenolpyruvate carboxylase (PEPC) in leaves of eggplant seedlings, but PEPC activity was low. KHCO3 could improve ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity and PEPC activity. From impact factors, HCO3- could enhance photosynthetic rate. K+ could raise stomatal conductance of eggplant seedlings. HCO3- could improve activity of PEPC . Both HCO3- and K+ could increase Rubisco activity.

scholarly journals Photosynthetic Characteristics of Four Wild Dendrobium Species in China

HortScience ◽  
2014 ◽  
Vol 49 (8) ◽  
pp. 1023-1027
Author(s):  
Gang-Yi Wu ◽  
Jun-Ai Hui ◽  
Zai-Hua Wang ◽  
Jie Li ◽  
Qing-Sheng Ye
Keyword(s):  
Glycolate Oxidase ◽  
Photosynthetic Pathway ◽  
Light Saturation ◽  
Saturation Point ◽  
Apparent Quantum Yield ◽  
Bisphosphate Carboxylase ◽  
Photosynthetic Physiology ◽  
Light Saturation Point ◽  
Second Peak ◽  
Dendrobium Densiflorum

Photosynthetic physiology of Dendrobium nobile, Dendrobium pendulum, Dendrobium chrysotoxum, and Dendrobium densiflorum was studied. A bimodal diurnal variation of the net photosynthetic rate (Pn) was observed in the four Dendrobium species with the first peak [5.09 to 6.06 μmol (CO2) per m−2·s−1] ≈1100 hr and the second peak [3.83 to 4.58 μmol (CO2) per m−2·s−1] at 1500 hr. No CO2 fixation was observed at night. For all four Dendrobium species, the light compensation point (LCP) was 5 to 10 μmol·m−2·s−1, light saturation point (LSP) ranged from 800 to 1000 μmol·m−2·s−1, apparent quantum yield (AQY) was 0.02, and CO2 compensation points (CCP) and saturation point (CSP) were 60 to 85 μmol·mol−1 and 800 to 1000 μmol·mol−1, respectively. Carboxylation efficiency (CE) values ranged from 0.011 to 0.020. The optimum temperature for photosynthesis was between 26 and 30 °C. The measurement of Pn seasonal variation indicated that July to August had the higher Pn for Dendrobium species. Additionally, the chlorophyll a/b (Chl a/b) ratios of the leaves were 2.77 to 2.89. Measurement of key enzymes in the photosynthetic pathway indicated relatively high Ribulose-1,5-bisphosphate carboxylase (RuBPCase) and glycolate oxidase (GO) activities but very low phosphoenolpyruvate carboxylase (PEPCase) activities. It suggested that these four Dendrobium species are typical semishade C3 plants.

The Photosynthetic Characteristics of Moso Bamboo (Phyllostachys pubescens) for Different Canopy Leaves

2013 ◽  
Vol 726-731 ◽  
pp. 4274-4279
Author(s):  
Yong Hui Cao ◽  
Ben Zhi Zhou ◽  
Xiao Ming Wang ◽  
Gang Wang
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Lower Layer ◽  
Middle Layer ◽  
B Value ◽  
Phyllostachys Pubescens ◽  
Light Saturation ◽  
Saturation Point ◽  
Low Light ◽  
Light Saturation Point

The carbon sequestration ability of different ages of Phyllostachys pubescens was analyzed at three canopy layers with a LI-6400 portable photosynthesis system. Under different photosynthetically active radiation (PAR), the net photosynthetic rate (Pn) of upper and middle layers of 3-year old bamboo were significantly higher than that of lower layer. When the light was greater than 800 umol·m-2·s-1, the Pn of bamboo in middle layer was in the order of 3-year-old > 4-year- old >2-year-old >7-year-old bamboo. When the light was greater than 500 umol·m-2·s-1, Pn of lower layer was in the order of 3-year old > 4-year old >2-year old, while in the order of 3-year-old > 2-year -old >4-year-old bamboo during the low light range (PAR<200 umol·m-2·s-1).The chlorophyll a/b value, maximum net photosynthetic rate, light compensation point and light saturation point values change were reduced gradually with the decrease of canopy height.

Photosynthetic responses of three C4 grasses of different metabolic subtypes to water deficit

2007 ◽  
Vol 34 (3) ◽  
pp. 204 ◽  
Author(s):  
Ana E. Carmo-Silva ◽  
Ana S. Soares ◽  
Jorge Marques da Silva ◽  
Anabela Bernardes da Silva ◽  
Alfred J. Keys ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Cynodon Dactylon ◽  
Net Photosynthesis ◽  
C3 Plants ◽  
C4 Grasses ◽  
Natural Habitats ◽  
Bisphosphate Carboxylase

C4 plants are considered to be less sensitive to drought than C3 plants because of their CO2 concentrating mechanism. The C4 grasses, Paspalum dilatatum Poiret (NADP-ME), Cynodon dactylon (L.) Pers (NAD-ME) and Zoysia japonica Steudel (PEPCK) were compared in their response to water deficit imposed by the addition of polyethylene glycol to the nutrient solution in which they were grown. The effects of drought on leaf relative water content (RWC), net photosynthesis, stomatal conductance, carboxylating enzyme activities and chlorophyll a fluorescence were investigated. In C. dactylon the RWC was more sensitive, but the photosynthetic activity was less sensitive, to water deficit than in P. dilatatum and Z. japonica. The decrease of photosynthesis in P. dilatatum under water deficit was not closely related to the activities of the carboxylating enzymes or to chlorophyll a fluorescence. However, decreased activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase, in addition to decreased stomatal conductance, may have contributed to the decrease of photosynthesis with drought in C. dactylon and Z. japonica. The different responses to water deficit are discussed in relation to the natural habitats of C4 grasses.

scholarly journals Methomyl Injury to Carbon Exchange Rates and Related Processes in Cotton

2017 ◽  
Author(s):  
C.E. Salem ◽  
J.T. Cothren ◽  
C.R. Benedict
Keyword(s):  
Exchange Rate ◽  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Carbon Exchange ◽  
Rubisco Activity ◽  
Bisphosphate Carboxylase ◽  
Chlorophyll Fluorescence Parameter ◽  
Fluorescence Parameter ◽  
Time Courses ◽  
Induced Changes

AbstractSome insecticides have the potential to cause varying levels of phytotoxicity. This study examined 1) the time courses of photosynthetic injury in cotton (Gossypium hirsutisms L.) leaves treated with methomyl [S-methyl-N-[(methyl carbamoyl)oxy]-thioacetimidate] and 2) the relationships between carbon exchange rate (CER), stomatal conductance, the chlorophyll fluorescence parameter FX/FP, and ribulose-1,5-bisphosphate carboxylase/ oxygenase (rubisco) activity. Plots were sprayed with either 0 or 0.84 kg methomyl·ha-1 when cotton was in mid-reproductive growth. Starting on the day of spraying, CER, stomatal conductance, FX/FP, and rubisco activity were measured daily for five consecutive days [4, 28, 52, 76 and 100 hours after spraying (HAS)]. In methomyl-treated leaves, CER decreased within hours after spraying, reached their lowest point at 28 HAS in experiment I and 76 HAS in experiment II, then recovered near-control levels by 100 HAS. At their lowest points, CER of methomyl-treated leaves decreased from 20 to 50% compared to controls. Stomatal conductance, FX/FP, and rubisco activity followed similar patterns to CER. Stomatal conductance was more closely related to CER than were FX/FP and rubisco activity. Chlorophyll fluorescence recovered more quickly than did CER. Rubisco activity did not decrease till after CER. From the parameters measured in this study, stomatal conductance appeared to be the major factor influencing methomyl-induced changes in CER, although all three parameters may be involved in the process of CER change.AbbreviationsCERcarbon exchange raterubiscoribulose-1,5-bisphosphate carboxylase/ oxygenaseDATdays after treatmentHAShours after spraying

Photoinhibition of Electron Transport Activity of Photosystem II in Isolated Thylakoids Studied by Thermoluminescence and Delayed Luminescence

1988 ◽  
Vol 43 (11-12) ◽  
pp. 871-876 ◽  
Author(s):  
Imre Vass ◽  
Narendranath Mohanty ◽  
Sándor Demeter
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Half Life ◽  
Delayed Luminescence ◽  
Transport Activity ◽  
Primary Target ◽  
Electron Transport Activity ◽  
The Stability ◽  
Spinach Thylakoids

Abstract The effect of photoinhibition on the primary (QA) and secondary (QB) quinone acceptors of photosystem I I was investigated in isolated spinach thylakoids by the methods of thermoluminescence and delayed luminescence. The amplitudes of the Q (at about 2 °C) and B (at about 30 °C) thermoluminescence bands which are associated with the recombination of the S2QA- and S2QB charge pairs, respectively, exhibited parallel decay courses during photoinhibitory treatment. Similarly, the amplitudes of the flash-induced delayed luminescence components ascribed to the recombination of S20A and S2OB charge pairs and having half life-times of about 3 s and 30 s, respectively, declined in parallel with the amplitudes of the corresponding Q and B thermoluminescence bands. The course of inhibition of thermoluminescence and delayed luminescence intensity was parallel with that of the rate of oxygen evolution. The peak positions of the B and Q thermoluminescence bands as well as the half life-times of the corresponding delayed luminescence components were not affected by photoinhibition. These results indicate that in isolated thylakoids neither the amount nor the stability of the reduced OB acceptor is preferentially decreased by photoinhibition. We conclude that either the primary target of photodamage is located before the O b binding site in the reaction center of photosystem II or QA and OB undergo simultaneous damage.

Effect of Magnesium and Calcium Ions on the Photoelectron Transport Activity of Low-Salt Suspended Hydrilla verticillata Thylakoids: Possible Sites of Cation Interaction

1998 ◽  
Vol 53 (9-10) ◽  
pp. 849-856
Author(s):  
Sujata R. Mishra ◽  
Surendra Chandra Sabat
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Donor ◽  
Water Oxidation ◽  
Electron Flow ◽  
Hydrilla Verticillata ◽  
Transport Activity ◽  
Low Salt ◽  
Electron Transport Activity ◽  
Stimulation Of

Stimulatory effect of divalent cations like calcium (Ca2+) and magnesium (Mg2+) was investigated on electron transport activity of divalent cation deficient low-salt suspended (LS) thylakoid preparation from a submerged aquatic angiosperm, Hydrilla verticillata. Both the cations stimulated electron transport activity of LS-suspended thylakoids having an intact water oxidation complex. But in hydroxylamine (NH2OH) - or alkaline Tris - washed thylakoid preparations (with the water oxidation enzyme impaired), only Ca2+ dependent stimulation of electron transport activity was found. The apparent Km of Ca2+ dependent stimulation of electron flow from H2O (endogenous) or from artificial electron donor (exogenous) to dichlorophenol indophenol (acceptor) was found to be identical. Calcium supported stimulation of electron transport activity in NH2OH - or Tris - washed thylakoids was electron donor selective, i.e., Ca2+ ion was only effective in electron flow with diphenylcarbazide but not with NH2OH as electron donor to photosystem II. A magnesium effect was observed in thylakoids having an intact water oxidation complex and the ion became unacceptable in NH2OH - or Tris - washed thylakoids. Indirect experimental evidences have been presented to suggest that Mg2+ interacts with the water oxidation complex, while the Ca2+ interaction is localized betw een Yz and reaction center of photosystem II.

Effects of Clone and Irrigation on the Stomatal Conductance and Photosynthetic Rate of Tea (Camellia sinensis)

1994 ◽  
Vol 30 (1) ◽  
pp. 1-16 ◽  
Author(s):  
B. Gail Smith ◽  
Paul J. Burgess ◽  
M. K. V. Carr
Keyword(s):  
Stomatal Conductance ◽  
Camellia Sinensis ◽  
Photosynthetic Rate ◽  
Leaf Temperature ◽  
Temperature Optimum ◽  
Photosynthetic Rates ◽  
Clone Selection ◽  
Treatment Interaction ◽  
Dry Seasons ◽  
The Relationship

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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