Mesembryanthemum crystallinum is an annual succulent plant that is being used as an emerging healthy leafy vegetable. To investigate the growth and physiological response of M. crystallinum to artificial lighting, five different light treatments were applied at 150 µmol(photon) m-2 s-1, which were white (W), different rations of red/blue (B) (15, 40, and 70%B), and blue (100%B), respectively. Our results showed that plants could gain as much as edible leaf area and dry mass with a certain ratio of blue (40%) in comparison with W. Plants grown under 100%B resulted in reduced photosynthetic rate, leaf area, and fresh mass compared with W. Adding blue fraction in the light regime enhanced the photosynthetic performance by influencing the amount of chlorophyll (Chl), Chl a/b, and specific leaf area. Under red/blue treatments, the electron transport rate and effective quantum yield of both PSII and PSI increased, while the nitrate content was reduced and flavonoids and total antioxidant capacity were unaffected.
Cyanobacterial NDH-1 interacts with PSI to form NDH-1-PSI supercomplex. CpcG2, a linker protein for the PSI-specific peripheral antenna CpcG2-phycobilisome, is essential for stabilization of the supercomplex. Green light (GL) increased the expression of CpcG2 but had little effect, if any, on the expression of NDH-1 and PSI, when compared to the abundance of these components under red light (RL). The increased expression of CpcG2 intensified the band of NDH-1-PSI supercomplex after blue-native gel electrophoresis of the thylakoid membrane, possibly by stabilizing the supercomplex. The activity of NDH-1-dependent cyclic electron transport around PSI increased when cells grown under RL were transferred to a low intensity GL but was suppressed when cells were grown under high intensities of GL. The functionality of PSI showed the same trend. We thus conclude that GL increases the expression of CpcG2, thereby increasing the abundance of the NDH-1-PSI supercomplex and its activity at low GL but not at higher GL., F. Gao, T. Ogawa, W. Ma., and Obsahuje bibliografické odkazy
This study evaluated the photosynthetic responses of Cucumis sativus leaves acclimated to illumination from three-band white fluorescent lamps with a high red:far-red (R:FR) ratio (R:FR = 10.5) and the photosynthetic responses of leaves acclimated to metal-halide lamps that provided a spectrum similar to that of natural light (R:FR = 1.2) at acclimation photosynthetic photon flux density (PPFD) of 100 to 700 μmol m-2 s-1. The maximum gross photosynthetic rate (PG) of the fluorescent-acclimated leaves was approximately 1.4 times that of the metal-halide-acclimated leaves at all acclimation PPFDs. The ratio of quantum efficiency of photosystem II (ΦPSII) of the fluorescent-acclimated leaves to that of the metal-halide-acclimated leaves tended to increase with increasing acclimation PPFD, whereas the corresponding ratios for the leaf mass per unit area tended to decrease with increasing acclimation PPFD. These results suggest that the greater maximum PG of the fluorescent-acclimated leaves resulted from an interaction between the acclimation light quality and quantity, which was mainly caused by the greater leaf biomass for photosynthesis per area at low acclimation PPFDs and by the higher ΦPSII as a result of changes in characteristics and distribution of chloroplasts, or a combination of these factors at high acclimation PPFDs., T. Shibuya .... [et al.]., and Obsahuje bibliografii
Although maize (Zea mays L.) plants utilize light efficiently, the expression of high light-efficient genes and stomatal factors is regulated by light conditions and affects photosynthesis of plants. In this study, we investigated the effects of different light qualities on the expression of the photosynthetic genes, such as pep1, pdk1, ZmSTOMAGEN, and psad1, and on stomatal function in maize seedlings. For both maize genotypes, Zhengdan 958 and Xianyu 335, light with wavelengths shorter than 490 nm enhanced the expression of pdk1 and ZmSTOMAGEN, whereas the expression of pdk1 positively correlated with ZmSTOMAGEN. Light with wavelengths longer than 630 nm or shorter than 490 nm (band pass filter) increased the expression of pep1 and psad1. Although the expression of four genes in Zhengdan 958 was significantly higher than that of Xianyu 335, changes in the expression of ZmSTOMAGEN, pdk1, or pep1 exerted no significant influence on stomatal function and photosynthetic rate. Our results suggest that light with wavelengths shorter than 490 nm promoted the expression of stomatal proteins and pdk1, facilitated the absorption of inorganic elements, and contributed to stomatal function in photosynthesis. Meanwhile, light with wavelengths longer than 630 nm inhibited the expression of pep1 and pdk1. Light with wavelengths longer than 630 nm or shorter than 490 nm promoted the expression of pep1, pdk1, and psad1., T. D. Liu, X. W. Zhang, Y. Xu, S. Q. Liu, X. W. Chen., and Obsahuje bibliografii