Search

Start Over Format bez média Language Multiple languages

1052. Greening of peas: parallel measurements of 77 K emission spectra, OJIP chlorophyll a fluorescence transient, period four oscillation of the initial fluorescence level, delayed light emission, and P700

Creator:
Srivastava, A., Strasser, R. J., and Govindjee
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
intermittent irradiation, photosystem 2, and Pisum sativum
Language:
Multiple languages
Description:
Irradiation of etiolated leaves leads to their greening. Although this problem has a long history, the question of whether the intermittent irradiation (IMI) grown plants have fully functional reaction centres as well as the oxygen clock, before exposure to continuous irradiation (CI), had not been resolved. To answer this question, as well as to analyze the development of the two photosystems, the following parallel measurements were made: (1) Emission spectra at 77 K; (2) OJIP chlorophyll (Chl) a fluorescence transient; (3) period 4 oscillation in the flash number dependence of initial fluorescence F0 (at 50 µs) and FJ (at 2 ms); and (4) P700. In the 1-ms-flash (FL) grown pea, that has a different biogenesis of the photosynthetic apparatus, delayed light emission (DLE) and Chl a fluorescence transient were measured in parallel. Quantitative analysis of Chl a fluorescence values provided the following conclusions: (1) IMI, not FL, plants have almost fully developed reaction centres and the oxygen clock. (2) Further greening of IMI plants under CI involves two phases: (a) during 3-4 h of CI, the number of PS2 units and connectivity between them increase, and then (b) light-harvesting antenna increases. (3) In FL, 10 min CI activates fully the oxygen clock. and A. Srivastava, R. J. Strasser, Govindjee.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1055. Growth and ecophysiological response in juvenile clones of Guadua (Guaduinae: Bambusoideae) cultivated in an altered lowland tropical region

Creator:
Ely, F., Araque, O., and Jaimez, R.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
bambus, fotosyntéza, Bamboo, photosynthesis, Venezuela, chlorofyl a fluorescence, vodní potenciál listu, chlorophyll a fluorescence, leaf water potentials, 2, and 581
Language:
Multiple languages
Description:
Guadua amplexifolia and Guadua angustifolia are the most promising timber substitutes amongst American bamboos due to their outstanding dimensions and structural properties. Despite the commercial potential of these species, there are few studies on the survival and adaptability of juveniles in plantations. The present study dealt with survival, growth, and ecophysiological response of juvenile clonal plants of these species, cultivated in abandoned pastures in Mérida, Venezuela. Survivorship, growth (height and culm diameter), and ecophysiological parameters were monitored the first year during wet and dry seasons. Survival rates were high in both species (95% in G. amplexifolia and 89% in G. angustifolia). Midday leaf water potentials decreased in both species during dry months (-1.28 to-2.72 MPa in G. amplexifolia and-1.67 to-2.37 MPa in G. angustifolia, respectively). Net photosynthetic rates measured during wet [16.57 ± 1.40 and 13.68 ± 2.40 μmol(CO2) m-2 s-1, respectively] and dry seasons [12.19 ± 2.82 and 8.12 ± 1.81 μmol(CO2) m-2 s-1, respectively], demonstrated that G. amplexifolia maintained consistently higher photosynthetic rates compared to G. angustifolia, which could explain the higher growth rates of the former. Similar trends were observed for stomatal conductance, transpiration, water-use efficiency, electron transport rate, and photochemical quenching of PSII. G. angustifolia maintained higher nonphotochemical quenching as well as a higher consumption of electrons per molecule of CO2 fixed, indicating a lower photosynthetic efficiency. The maximal photochemical efficiency of PSII (0.73-0.76) suggested that neither of these species suffered from photoinhibition, despite persistently high radiation and air temperatures at the study site., F. Ely, O. Araque, R. Jaimez., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1056. Growth and leaf gas exchange characteristics in Dalbergia sissoo Roxb. and D. latifolia Roxb. under water deficit

Creator:
Ashraf, M., Ashraf, M. Y., Khaliq, Abdul, and Rha, Eui Shik
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
net photosynthetic rate, stomatal conductance, transpiration, and water use efficiency
Language:
Multiple languages
Description:
Forty two-month-old plants of Dalbergia sissoo and D. latifolia were subjected for 56 d to water deficit induced by withholding water. Drought stress caused a significant reduction in plant height, stem diameter, net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) in both species, but the reduction was greater in D. sissoo than in D. latifolia. Water use efficiency (PN/E) was adversely affected due to water stress only in D. latifolia, and intrinsic water use efficiency (PN/gs) was increased in both species. There was a slight effect of water stress on variable to maximum fluorescence (Fv/Fm) (quantum yield of photosystem 2) in both species, but the species did not differ significantly in this attribute. and M. Ashraf ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1057. Growth and leaf gas exchange in Populus euphratica across soil water and salinity gradients

Creator:
Li, J. Y., Zhao, C. Y., Li, J., Yan, Y. Y., Yu, B., and Han, M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, chlorophyll fluorescence, seedling, water and salt stress, 2, and 581
Language:
Multiple languages
Description:
Soil water and salinity conditions of the riparian zones along the Tarim River, northwest China, have been undergoing alterations due to water use by human or climate change, which is expected to influence the riparian forest dominated by an old poplar, Populus euphratica. To evaluate the effects of such habitat alterations, we examined photosynthetic and growth performances of P. euphratica seedlings across experimental soil water and salinity gradients. Results indicated that seedlings were limited in their physiological performance, as evidenced by decreases in their height and biomass, and the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), the effective quantum-use efficiency of PSII (Fv′/Fm′), and photochemical quenching (qP) under mild (18% soil water content, SWC; 18.3 g kg-1 soil salt content, SSC) and moderate (13% SWC, 22.5 g kg-1 SSC) water or salinity stress. However, seedlings had higher root/shoot ratio (R/S), increased nonphotochemical quenching (NPQ), and water-use efficiency (WUE) relative to control under such conditions. Under severe (8% SWC, 27.9 g kg-1 SSC) water or salinity stress, P. euphratica seedlings had only a fifth of biomass of those under control conditions. It was also associated with damaged PSII and decreases in WUE, the maximal net photosynthetic rate (P Nmax), light-saturation point (LSP), and apparent quantum yield (α). Our results suggested that the soil conditions, where P. euphratica seedlings could grow normally, were higher than ∼13% for SWC, and lower than ∼22.5 g kg-1 for SSC, the values, within the seedlings could acclimate to water or salinity stress by adjusting their R/S ratio, improving WUE to limit water loss, and rising NPQ to dissipate excessive excitation energy. Once SWC was lower than 8% or SCC higher than ∼28 g kg-1, the seedlings suffered from the severe stress. and J. Y. Li ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1058. Growth and photosynthetic and biochemical responses of tea cultivars to blister blight infection

Creator:
Premkumar, R., Ponmurugan, P., and Manian, S.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Camellia species, chlorophyll, clone differences, Exobasidium vexans, fresh and dry masses, hybrids, net photosynthetic rate, stomatal conductance, stomatal index, and transpiration
Language:
Multiple languages
Description:
Growth characteristics such as leaf area, fresh and dry mass, and shoot length, and physiological parameters such as photosynthetic and transpiration rates, stomatal conductance, and water use efficiency were reduced by blister blight significantly more in a susceptible tea clone TES-34 than in a tolerant clone SA-6. Also the contents of total sugars, nitrogen, amino acids, proteins, polyphenols, and catechin were reduced more in diseased plant leaves. However, the reduction was more prominent in susceptible than in tolerant clone. Among the different hybrids of tea, Assam hybrid UPASI-3 was highly susceptible to blister blight followed by Cambod UPASI-27 and China UPASI-9. Similarly, tea seedling cv. Caline was highly susceptible to blister blight when compared to tea clone UPASI-3. Susceptibility of tea cultivars to blister blight infection is connected with many physical barriers including leaf area, shoot length, moisture contents, and other physiological and biochemical parameters. and R. Premkumar, P. Ponmurugan, S. Manian.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1059. Growth and photosynthetic characteristics in pearl millet under water stress and different potassium supply

Creator:
Ashraf, M., Ahmad, Ashfaq, and McNeilly, T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
drought, leaf area, net assimilation rate, net photosynthetic rate, relative growth rate, stomatal conductance, supra-optimal nutrition, transpiration rate, water potential, and water use efficiency
Language:
Multiple languages
Description:
Influence of supra-optimal concentrations of K on growth, water relations, and photosynthetic capacity in pearl millet under severe water deficit conditions was assessed in a glasshouse. Nineteen-days-old plants of two lines, ICMV-94133 and WCA-78, of Pennisetum glaucum (L.) R.Br. were subjected for 30 d to 235.0, 352.5, and 470.0 mg(K) kg-1(soil) and two water regimes (100 and 30 % field capacity). Increasing K supply did not alleviate the effect of water deficit on the growth of two lines of pearl millet since additional amount of K in the growth medium had no effect on shoot dry mass, relative growth rate, plant leaf area, net assimilation rate, or leaf area ratio, although there was significant effect of drought stress on these variables. Soil moisture had a significant effect on net photosynthetic rate (PN), transpiration rate, stomatal conductance, and water use efficiency of both pearl millet lines, but there was no significant effect of varying K supply on these variables. In WCA-78 an ameliorative effect of increasing supply of K on PN was observed under water deficit. Chlorophyll (Chl) a and b contents increased significantly in both lines with increase in K supply under well watered conditions, but under water deficit they increased only in ICMV-94133. Chl a/b ratios were reduced significantly in WCA-78 with increasing K supply under both watering regimes, but by contrast, in ICMV-94133 this variable was decreased only under water stress. Leaf water potential and osmotic potential of both lines decreased significantly with the imposition of drought. Leaf pressure potential in both lines increased with increase in K supply under water stress. Contents of total free amino acids in the leaves of both pearl millet lines increased significantly with increase in K supply under water stress. Potassium supply had no effect on leaf soluble sugars or soluble proteins. Considerable osmotic adjustment occurred in pearl millet plants experiencing water deficit under high K supply. and M. Ashraf, Ashfaq Ahmad, T. McNeilly.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1060. Growth and photosynthetic characteristics of Ceriops roxburghiana under NaCl stress

Creator:
Rajesh, A., Arumugam, R., and Venkatesalu, V.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
carbon assimilation pathway, chlorophyll, intercellular CO2 concentration, phosphoenolpyruvate carboxylase, ribulose-1,5-bisphosphate carboxylase, and salinity
Language:
Multiple languages
Description:
The plant growth, net photosynthetic rate (PN), intercellular CO2 concentration (ci), and dry matter production of Ceriops roxburghiana Arn. were significantly increased with increasing salinity from 0 to 400 mM NaCl. At 600 mM NaCl, shoot and root lengths, and dry mass were significantly depressed with respect to control. Absence of diurnal fluctuation of concentrations of organic acids, and the low activity of phosphoenolpyruvate carboxylase and high activity of ribulose-1,5-bisphosphate carboxylase confirmed the operation of C3 pathway in Ceriops even at increasing salinity. and A. Rajesh, R. Arumugam, V. Venkatesalu.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

Limit your search