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Start Over Coverage 301-305

2. Nitrogen fixation and pigment contents of the symbiont Anabaena azollae from Azolla

Creator:
Samal, K.C. and Kannaiyan, S.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
Five cyanobacterial symbionts from Azolla filiculoides, two symbionts from Az. microphylla and two free-living cyanobacteria Nos toe muscorum and Anabaena variabilis were analyzed for chlorophyll (Chi) a, carotenoids and phycobiliprotein contents, heterocyst frequency and nitrogenase activity. The symbiont AS-S1 as well as the free-living N. muscorum and An. variabilis contained highest amounts of Chi a and lowest amounts of carotenoids. The C-phycocyanin content was always higher than that of allo-phycocyanin and C-phycoerythrin. Among the symbionts, AS-S1 contained the highest amount of C-phycocyanin and highest nitrogenase activity. Heterocysts were more abundant in An. azollae than in free-living cyanobacteria.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. On the nature of the component stars in Beta Lyrae

Creator:
Plavec, Mirek J.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
spectrophotometry, Beta Lyrae, and component stars
Language:
Czech
Description:
An attempt has been made to determine the continuous flux distribution separately for the two components of β Lyrae, first from optical spectrophotometric scans, then from ultraviolet (IUE) spectra. Both components have anomalous flux distribution not matching any standard star. For the primary, this is probably due to its Roche lobe filling; the secondary is a disk.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Photosynthetic response of carrots to varying irradiances

Creator:
Kyei-Boahen, S., Lada, R., Astatkie, T., Gordon, R., and Caldwell, C.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
compensation irradiance, Daucus carota, net photosynthetic rate, nonlinear regression model, quantum yield, stomatal conductance, transpiration rate, and water use efficiency
Language:
Multiple languages
Description:
Response to irradiance of leaf net photosynthetic rates (PN) of four carrot cultivars: Cascade, Caro Choice (CC), Oranza, and Red Core Chantenay (RCC) were examined in a controlled environment. Gas exchange measurements were conducted at photosynthetic active radiation (PAR) from 100 to 1 000 μmol m-2 s-1 at 20 °C and 350 μmol (CO2) mol-1(air). The values of PN were fitted to a rectangular hyperbolic nonlinear regression model. PN for all cultivars increased similarly with increasing PAR but Cascade and Oranza generally had higher PN than CC. None of the cultivars reached saturation at 1 000 μmol m-2 s-1. The predicted PN at saturation (PNmax) for Cascade, CC, Oranza, and RCC were 19.78, 16.40, 19.79, and 18.11 μmol (CO2) m-2 s-1, respectively. The compensation irradiance (I c) occurred at 54 μmol m-2 s-1 for Cascade, 36 μmol m-2 s-1 for CC, 45 μmol m-2 s-1 for Oranza, and 25 μmol m-2 s-1 for RCC. The quantum yield among the cultivars ranged between 0.057-0.033 mol(CO2) mol-1(PAR) and did not differ. Dark respiration varied from 2.66 μmol m-2 s-1 for Cascade to 0.85 μmol m-2 s-1 for RCC. As PN increased with PAR, intercellular CO2 decreased in a non-linear manner. Increasing PAR increased stomatal conductance and transpiration rate to a peak between 600 and 800 μmol m-2 s-1 followed by a steep decline resulting in sharp increases in water use efficiency. and S. Kyei-Boahen ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public