It is shown that a Banach-valued Henstock-Kurzweil integrable function on an m-dimensional compact interval is McShane integrable on a portion of the interval. As a consequence, there exist a non-Perron integrable function f : [0, 1]2 −→ R and a continuous function F : [0, 1]2 −→ R such that
(P)∫ x0{ (P) ∫ y 0 f(u, v) dv } du = (P) ∫ y 0 { (P) ∫ x 0 f(u, v) du } dv = F(x, y) for all (x, y) ∈ [0, 1]2.
The function of chloroplast ferredoxin quinone reductase (FQR)-dependent flow was examined by comparing a wild type tobacco and a tobacco transformant (ΔndhB) in which the ndhB gene had been disrupted with their antimycin A (AA)-fed leaves upon exposure to chilling temperature (4 °C) under low irradiance (100 µmol m-2 s-1 photon flux density). During the chilling stress, the maximum photochemical efficiency of photosystem (PS) 2 (Fv/Fm) decreased markedly in both the controls and AA-fed leaves, and P700+ was also lower in AA-fed leaves than in the controls, implying that FQR-dependent cyclic electron flow around PS1 functioned to protect the photosynthetic apparatus from chilling stress under low irradiance. Under such stress, non-photochemical quenching (NPQ), particularly the fast relaxing NPQ component (qf) and the de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z), formed the difference between AA-fed leaves and controls. The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes (ΔpH) because of inhibiting an FQR-dependent cyclic electron flow around PS1 at chilling temperature under low irradiance. and X.-G. Li ... [et al.].
We checked the hypothesis that the transient presence of anthocyanins in young leaves serves a photoprotective function. For this purpose, Rosa sp. and Ricinus communis L., whose young leaves are red to become green upon maturation, were used. Thus, young leaves with high and mature leaves with low anthocyanin contents were analysed concerning their carotenoid (Car) composition and susceptibility to photoinhibition. Cars, including the components of the xanthophyll cycle, had similar contents in young and mature leaves, when expressed on a chlorophyll basis. Yet, when expressed on a leaf area basis or on the assumed photon absorptive capacity of leaves, Cars contents were considerably lower in anthocyanic young leaves. Although this may indicate a low photodissipative potential, red young leaves were considerably less susceptible to photoinhibitory damage. The results are compatible with a photoprotective function of anthocyanins, indicating also that their presence may compensate for a low capacity in the xanthophyll cycle-dependent harmless dissipation of excess excitation energy. and Y. Manetas, A. Drinia, Y. Petropoulou.