High Light-Induced Reduction and Low Light-Enhanced Recovery of Photon Yield in Triazine-Resistant Brassica napus L

Abstract

Triazine-resistant and -susceptible Brassica napus L. plants grown under low photon flux density (PFD) have previously been shown to exhibit a similar photon yield. In contrast, high PFDgrown resistant plants have a lower photon yield than high PFD- This work was initiated to test the hypothesis that high PFD light causes the differential reduction in photon yield observed in resistant plants. We exposed low PFD-grown B. napus leaf discs to high PFD and measured photon yield and other photosynthetic traits. We found that exposure to high PFD induces a differential decrease in photon yield in resistant plants. We also observed that the characteristics of recovery from decreased photon yield are consistent with the hypothesis that resistant plants are more sensitive to photoinhibition of PSII than susceptible plants. MATERIALS AND METHODSThe development of triazine resistance in crop plants is an attractive goal because of the potential benefits it offers for weed control.

Molecular Basis of Resistance to <i>s</i>-Triazine Herbicides in <i>Poa annua</i> L. and Its Photosynthetic Properties under Different Light Conditions

“…These results indicate that the R biotype may have no loss of photosynthetic performance when grown in the low light intensities. Similar results have been obtained for s-triazine resistant B. napus L. 13,14) This tendency was also confirmed by the chlorophyll a fluorescence measurements. The Fv/Fm values in the R (S) biotype were 0.…”

“…In addition, plants adapted to or grown in shade are generally more susceptible to photoinhibition. Since the s-triazine resistant plants carrying the Ser-Gly mutation have been shown to be susceptible to photoinhibition than wild types due to more stable formation of double-reduced QA, which has been believed as a primary event of photoinhibition, 13,14,34) response to a photoinhibitory treatment (strong light exposure) of the S and R biotypes of P. annua was examined by using 12-week-old seedlings grown under different light conditions. Leaf segments from both biotypes grown either under shaded or full-sunlight conditions for 12 weeks were subjected to photoinhibitory treatment, irradiation with strong light (ca.…”

Similar Photosynthetic Performance in Low Light-Grown Isonuclear Triazine-Resistant and -Susceptible Brassica napus L

“…,imilar small difference in photon yield may Further evidence that the resistance alteration causes slow nt in low PFD growth chamber-grown plants Qa to Qb electron transfer in low PFD-grown plants comes from the oxygen flash yield data. As seen in Table II 6,20) and in resistant chloroplasts (5,20 (12), high PFD exposure does indeed cause a differential lowering of photon yield in resistant leaf discs. Our evidence suggests that the decrease in photon yield in resistant plants is due to increased sensitivity of Dl to photoinhibitory damage (12).…”

A D1 protein mutáció hatása a kettes fotokémiai rendszer energiahasznosítására eltérő vízellátású növényekben

“…Az AR növények tilakoid membránjainak lipid mátrixa a fluoreszcencia polarizációs mérések tanúsága szerint nagyobb fluiditást mutat az AS növényekéhez viszonyítva (Lehoczki et al, 1985). Az AR biotípusok nagyobb fényérzékenységéről és a fénygátlással szembeni nagyobb érzékenységről egyaránt beszámoltak (Holt et al, 1981, Hart & Stemler, 1990Curwiel et al, 1993;Sundby et al, 1993a;Váradi et al, 1994;Darkó et al, 1996;.…”

“…Ismeretes az atrazin-rezisztens növények eltérő hőmérséklet-érzékenysége és adaptációs képessége (Ducruet & Lemoine, 1985), illetve fokozott fényérzékenységükről egyaránt beszámoltak (Hart & Stemler, 1990). Tudomásunk szerint a vízdeficit (szárazság)…”