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1462. Allometric model for nondestructive leaf area estimation in clary sage (Salvia sclarea L.)

Creator:
Kumar, R. and Sharma, S.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, clary sage, nondestructive, regression model, Salvia sclarea, and validation
Language:
Multiple languages
Description:
Leaf area estimation is an important biometrical observation recorded for evaluating plant growth in field and pot experiments. In this study, conducted in 2009, a leaf area estimation model was developed for aromatic crop clary sage (Salvia sclarea L.), using linear measurements of leaf length (L) and maximum width (W). Leaves from four genotypes of clary sage, collected at different stages, were used to develop the model. The actual leaf area (LA) and leaf dimensions were measured with a Laser Area meter. Different combinations of prediction equations were obtained from L, W, product of LW and dry mass of leaves (DM) to create linear (y = a + bx), quadratic (y = a + bx + cx2), exponential (y = aebx), logarithmic (y = a + bLnx), and power models (y = axb) for each genotype. Data for all four genotypes were pooled and compared with earlier models by graphical procedures and statistical measures viz. Mean Square Error (MSE) and Prediction Sum of Squares (PRESS). A linear model having LW as the independent variables (y = -3.4444 + 0.729 LW) provided the most accurate estimate (R 2 = 0.99, MSE = 50.05, PRESS = 12.51) of clary sage leaf area. Validation of the regression model using the data from another experiment showed that the correlation between measured and predicted values was very high (R 2 = 0.98) with low MSE (107.74) and PRESS (26.96). and R. Kumar, S. Sharma.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1463. Allometric models for leaf area estimation across different leaf-age groups of evergreen broadleaved trees in a subtropical forest

Creator:
Zhang, L. and Pan, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, evergreen broadleaved trees, leaf age, leaf area, leaf length and width, and subtropical forest
Language:
Multiple languages
Description:
The accurate and nondestructive determination of individual leaf area (LA) of plants, by using leaf length (L) and width (W) measurement or combinations of them, is important for many experimental comparisons. Here, we propose reliable and simple regressions for estimating LA across different leaf-age groups of eight common evergreen broadleaved trees in a subtropical forest in Gutianshan Natural Reserve, eastern China. During July 2007, the L, W, and LA of 2,923 leaves (202 to 476 leaves for each species) were measured for model construction and the respective measurements on 1,299 leaves were used for model validation. Mean L, W, LA and leaf shape (L:W ratio) differed significantly between current and older leaves in four out of the eight species. The coefficients of one-dimension LA models were affected by leaf age for most species while those incorporating both leaf dimensions (L and W) were independent of leaf age for all the species. Therefore, the regressions encompassing both L and W (LA = a L W + b), which were independent of leaf age and also allowed reliable LA estimations, were developed. Comparison between observed and predicted LA using these equations in another dataset, conducted for model validation, exhibited a high degree of correlation (R 2 = 0.96-0.99). Accordingly, these models can accurately estimate the LA of different age groups for the eight evergreen tree species without using instruments. and L. Zhang, L. Pan.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1465. Alteration of components of chlorophyll-protein complexes and distribution of excitation energy between the two photosystems in two new rice chlorophyll b-less mutants

Creator:
Lin, Zhi-Fang, Peng, Chang-Lian, Lin, Gui-Zhu, and Zhang, Jing-Liu
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, chlorophyll-protein complexes, Mg2+, photosystems 1 and 2, and Oryza
Language:
Multiple languages
Description:
Two new yellow rice chlorophyll (Chl) b-less (lack) mutants VG28-1 and VG30-5 differ from the other known Chl b-less mutants with larger amounts of soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase small sub-unit and smaller amounts of Chl a. We investigated the altered features of Chl-protein complexes and excitation energy distribution in these two mutants, as compared with wild type (WT) rice cv. Zhonghua 11 by using native mild green gel electrophoresis and SDS-PAGE, and 77 K Chl fluorescence in the presence of Mg2+. WT rice revealed five pigment-protein bands and fourteen polypeptides in thylakoid membranes. Two Chl b-less mutants showed only CPI and CPa pigment bands, and contained no 25 and 26 kDa polypeptides, reduced amounts of the 21 kDa polypeptide, but increased quantities of 32, 33, 56, 66, and 19 kDa polypeptides. The enhanced absorption of CPI and CPa and the higher Chl fluorescence emission ratio of F685/F720 were also observed in these mutants. This suggested that the reduction or loss of the antenna LHC1 and LHC2 was compensated by an increment in core component and the capacity to harvest photon energy of photosystem (PS) 1 and PS2, as well as in the fraction of excitation energy distributed to PS2 in the two mutants. 77 K Chl fluorescence spectra of thylakoid membranes showed that the PS1 fluorescence emission was shifted from 730 nm in WT rice to 720 nm in the mutants. The regulation of Mg2+ to excitation energy distribution between the two photosystems was complicated. 10 mM Mg2+ did not affect noticeably the F685/F730 emission ratio of WT thylakoid membranes, but increased the ratio of F685/F720 in the two mutants due to a reduced emission at 685 nm as compared to that at 720 nm. and Zhu-Fang Lin ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1466. Alterations in electron transport characteristics during senescence of Cucumis cotyledonary leaves. Analysis of the effects of inhibitors

Creator:
Prakash, J. S. S., Baig, M. A., and Mohanty, Prasanna
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
atrazine, cucumber, DCMU, dibromothymoquinone, KCN, photosystems 1 and 2, plant age, and thylakoid proteins
Language:
Multiple languages
Description:
Cotyledonary leaves of Cucumis sativus cv. Poinsette exhibited senescence-induced losses in chlorophyll (Chl) and protein contents within three weeks since germination. Chl and protein concentrations in cotyledonary leaves approached maximum on 6th d after germination and they declined to 50 and 41 %, respectively, by the 20th day of growth. Activities of both photosystem (PS) 2 and PS1 decreased by 33 and 31 %, respectively, on the 20th day, compared to the control 6th day. Changes in sensitivity of PS2 to inhibitors like atrazine and dibromothymoquinone and sensitivity of PS1 to KCN accompanied the changes in PS2 and PS1 activities. Hence both the acceptor side of PS2 and the donor side of PS1 are affected by senescence-induced changes in cucumber cotyledonary leaves. and J. S. S. Prakash, M. A. Baig, Prasanna Mohanty.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1467. Alterations in photosynthesis and antioxidant enzyme activity in winter wheat subjected to post-anthesis water-logging

Creator:
Tan, W., Liu, J., Dai, T., Jing, Q., Cao, W., and Jiang, D.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
catalase, chlorophyll fluorescence; ;, dry matter redistribution, net photosynthetic rate, peroxidase, photosystem 2, superoxide dismutase, Triticum aestivum, and yield
Language:
Multiple languages
Description:
Winter wheat (Triticum aestivum L.) cultivars Yangmai 9 (water-logging tolerant) and Yumai 34 (water-logging sensitive) were subjected to water-logging (WL) from 7 d after anthesis to determine the responses of photosynthesis and anti-oxidative enzyme activities in flag leaf. At 15 d after treatment (DAT), net photosynthetic rate under WL was only 3.7 and 8.9 µmol(CO2) m-2 s-1 in Yumai 34 and Yangmai 9, respectively, which was much lower than in the control. Ratios of variable to maximum and variable to initial fluorescence, actual photosynthetic efficiency, and photochemical quenching were much lower, while initial fluorescence and non-photochemical quenching were much higher under WL than in control, indicating damage to photosystem 2. WL decreased activities of superoxide dismutase and catalase in both cultivars, and activity of peroxidase (POD) in Yumai 34, while POD activity in Yangmai 9 was mostly increased. The obvious decrease in the amount of post-anthesis accumulated dry matter, which was redistributed to grains, also contributed to the grain yield loss under WL. and W. Tan ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1468. Alternative cyanide-sensitive oxidase interacting with photosynthesis in synechocystis PCC6803. Ancestor of the terminal oxidase of chlororespiration?

Creator:
Büchel, C., Zsíros, O., and Garab, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
absorbance, azide, cyanobacteria, cytochromes, flash radiation, KCN, NaN3, phylogeny, respiration, and salicyl hydroxamic acid
Language:
Multiple languages
Description:
Influence of respiration on photosynthesis in Synechocystis PCC6803 was studied by measuring the redox transients of cytochrome f (cyt f) upon excitation of the cells with repetitive single turnover flashes. Upon the addition of KCN the flash-induced oxidation of cyt f was increased and the rereduction of cyt f+ was accelerated. Dependence of these effects on the concentration of KCN clearly demonstrated the existence of two cyanide-sensitive oxidases interacting with photosynthesis: cyt aa3, which was sensitive to low concentrations of cyanide, and an alternative oxidase, which could be suppressed by using ≥1 mM KCN. The interaction between the photosynthetic and the respiratory electron transport chains was regulated mainly by the activity of the alternative cyanide-sensitive oxidase. The oxidative pathway involving the alternative cyanide-sensitive oxidase was insensitive to salicyl hydroxamic acid and azide. The close resemblance of the inhibition pattern reported here and that described for chlororespiration in algae and higher plants strongly suggest that an oxidase of the same type as the alternative cyanide-sensitive oxidase of cyanobacteria functions as a terminal oxidase in chloroplasts. and C. Büchel, O. Zsíros, G. Garab.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1469. Altitude-related changes in activities of carbon metabolism enzymes in Rumex nepalensis

Creator:
Kumar, N., Kumar Vats, S., Kumar, S., and Ahuja, P. S.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
aspartate aminotransferase, citrate synthase, glutamine synthetase, malate dehydrogenase, NAD-malic enzyme, phosphoenolpyruvate carboxylase, ribulose-1,5-bisphosphate carboxylase, and oxygenase
Language:
Multiple languages
Description:
Activities of some enzymes related to carbon metabolism were studied in different ecotypes of Rumex nepalensis growing at 1 300, 2 250, and 3 250 m above mean sea level. Activities of ribulose-1,5-bisphosphate carboxylase/oxygenase, phosphoenolpyruvate carboxylase, aspartate aminotransferase, and glutamine synthetase increased with altitude, whereas activities of malate dehydrogenase, NAD-malic enzyme, and citrate synthase did not show a significant difference with change in altitude. and N. Kumar ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1470. Altitudinal changes in photosynthetic pathways of floristic elements in southern Sinai, Egypt

Creator:
Sayed, O. H. and Mohamed, M. K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
C3, C4, and ecophysiology
Language:
Multiple languages
Description:
High altitude profoundly influenced plant diversity and distribution on mountains of southern Sinai (Egypt). Plants exhibiting the C3-mode of photosynthesis were widely distributed along the altitudinal transect. Plants exhibiting the C4-mode were restricted below an altitude of about 1400 m above sea level. The transition from C3-dominated areas to C4-dominated areas occurred between 1200 and 1400 m a.s.l. and O. H. Sayed, M. K. Mohamed.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public