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Start Over Creator Yoshimura, Y.

1. Estimation of photorespiration rate by simultaneous measurements of CO2, gas exchange rate, and chlorophyll fluorescence quenching in the C3 plant Vigna radiata (L.) Wilczek and the C4 plant Amaranthus mongostanus L.

Creator:
Yoshimura, Y., Kubota, F., and Hirao, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
electron transport rate, photosynthesis, photosystem 2, mungbean, and quantum yield
Language:
Multiple languages
Description:
So far the photorespiration rate (RP) in a leaf has been determined as the difference between the net photosynthetic rates (PN) measured in 21 % O2 air (PN21%) and 3 % O2 air (PN3%). In the C3 plant Vigna radiata and the C4 plant Amaranthus mongostanus L., PN and chlorophyll fluorescence quenching in leaves were monitored simultaneously. RP of leaves in situ was estimated as termed RPE from the electron transport rates through photosystem 2 (PS2), and compared with RPO (PN3% - PN21%). In V. radiata RPO was 11.9 µmol(CO2) m-2 s-1 and the ratio of RPO to PN21% was 42.2 %, whereas the ratio of RPE to PN21% was 25.7 %. This suggests that RPO may be over-estimated for the real RP in normal air. In A. mongostanus, PN was almost not changed with a decrease in O2 concentration from 21 to 3 %, whereas the quantum yield of PS2 was evidently affected by the change in O2 concentration. This fact shows the presence of photorespiration in this C4 species, where RPE was equivalent to 3.8 % of PN21%. and Y. Yoshimura, F. Kubota, K. Hirao.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Estimation of photosynthetic activity from the electron transport rate of photosystem 2 in a film-sealed leaf of sweet potato, Ipomoea batatas Lam.

Creator:
Haimerong, Kubota, F., and Yoshimura, Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
C3-leaf, chlorophyll fluorescence, irradiance, leaf age, leaf-sealing method, leaf temperature, oxygen concentration, photorespiration, and respiration
Language:
Multiple languages
Description:
In order to evaluate the photosynthetic activity of a C3 leaf from the electron transport rate (ETR) of photosystem 2 (PS2), a new method was devised and examined using leaves of sweet potato. In this method, both surfaces of a leaf were sealed with transparent films to stop the gas exchange between the leaf and the atmosphere; hence the functions of both photosynthetic assimilation (CO2 uptake) and photorespiration (CO2 release) are restricted to the inside of the leaf. After both functional rates became equally balanced, ETR of the sealed leaf (ETRseal) was determined from the chlorophyll fluorescence. The measurements were conducted at different irradiances and leaf temperatures and by using leaves of different age. Under each measurement condition, ETRseal showed a close positive relationship with the photosynthetic potential, or the gross photosynthetic rate measured in the air of 2 % O2 (PG2%) before sealing. ETRseal may become an indicator to estimate or evaluate the photosynthetic activity of C3 leaves. and Haimeirong, F. Kubota, Y. Yoshimura.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public