In this study, effects of yellow (Y), purple (P), red (R), blue (B), green (G), and white (W) light on growth and development of tobacco plants were evaluated. We showed that monochromatic light reduced the growth, net photosynthetic rate (PN), stomatal conductance, intercellular CO2, and transpiration rate of tobacco. Such a reduction in PN occurred probably due to the stomatal limitation contrary to plants grown under W. Photochemical quenching coefficient (qP), maximal fluorescence of dark-adapted state, effective quantum yield of PSII photochemistry (ΦPSII), and maximal quantum yield of PSII photochemistry (Fv/Fm) of plants decreased under all monochromatic illuminations. The decline in ΦPSII occurred mostly due to the reduction in qP. The increase in minimal fluorescence of dark-adapted state and the decrease in Fv/Fm indicated the damage or inactivation of the reaction center of PSII under monochromatic light. Plants under Y and G showed the maximal nonphotochemical quenching with minimum PN compared with the W plants. Morphogenesis of plants was also affected by light quality. Under B light, plants exhibited smaller angles between stem and petiole, and the whole plants showed a compact type, while the angles increased under Y, P, R, and G and the plants were of an unconsolidated style. The total soluble sugar content increased significantly under B. The reducing sugar content increased under B but decreased significantly under R and G compared with W. In conclusion, different monochromatic light quality inhibited plants growth by reducing the activity of photosynthetic apparatus in plants. R and B light were more effective to drive photosynthesis and promote the plant growth, while Y and G light showed an suppression effect on plants growth. LEDs could be used as optimal light resources for plant cultivation in a greenhouse., L. Y. Yang, L. T. Wang, J. H. Ma, E. D. Ma, J. Y. Li, M. Gong., and Obsahuje bibliografii
The acclimation to high light, elevated temperature, and combination of both factors was evaluated in tomato (Solanum lycopersicum cv. M82) by determination of photochemical activities of PSI and PSII and by analyzing 77 K fluorescence of isolated thylakoid membranes. Developed plants were exposed for six days to different combinations of temperature and light intensity followed by five days of a recovery period. Photochemical activities of both photosystems showed different sensitivity towards the heat treatment in dependence on light intensity. Elevated temperature exhibited more negative impact on PSII activity, while PSI was slightly stimulated. Analysis of 77 K fluorescence emission and excitation spectra showed alterations in the energy distribution between both photosystems indicating alterations in light-harvesting complexes. Light intensity affected the antenna complexes of both photosystems stronger than temperature. Our results demonstrated that simultaneous action of high-light intensity and high temperature promoted the acclimation of tomato plants regarding the activity of both photosystems in thylakoid membranes., A. Faik, A. V. Popova, M. Velitchkova., and Obsahuje bibliografii
The four Fabaceae species of different chilling tolerance (Pisum sativum L., Glycine max. Merr., Phaseolus vulgaris L. and Vigna unguiculata L.) were subjected to simulated bad weather periods at the beginning of the growth season. The treatment parameters were 14 d at constant 10 “C, 100 pmol m-2 s"*, 80 % relative humidity within a 12 h photoperiod. During chilling and subsequent recovery, photosynthesis, chlorophyll fluorescence and assimilate concentrations, as well as ribulose-1,5- bisphosphate carboxylase/oxygenase (RuBPCO) activity were followed. Despite the observation that no significant photoinhibition had been induced by the treatment, French beán and cowpea showed a strong decrease of photosynthetic capacity within the first week. Diuring chilling, soybean, French beán and cowpea virtually did not grow fiirther, but acciunulated large amounts of starch, in contrast to pea. Specific activity of RuBPCO (Mg2+- and HC03'-activated) was not altered significantly by the chilling treatment. Yet in French beán a generál protein breakdovm occurred in the second week. At the same time, a very strong decrease of qp was obtained in this species, indicating a breakdown of the electron transport. Pea and soybean were not negatively afifected by the long-term chilling.
Wheat plants were cultivated in a growth chamber at normál (35 Pa, C35 plants) and enhanced (70 Pa, C70 plants) CO2 partial pressure. In C35 plants the net photosynthetic rate (P^) of flag leaves and the concentrations of saccharides such as sucrose, glucose, fructose and starch were increased. The C70 plants possessed higher chlorophyll (Chl) a and Chl b contents. The CO2 response of Pn at saturating photosynthetically active radiation (PAR) was very similar for both variants. At the highest CO2 concentration saccharides accumulated in both variants as a consequence of decreased export rate. The response of to ^t saturating CO2 concentrations was similar in the two variants. On the other hand, the response of water vapour pressure conductance (gH2o) to PAR in C35 plants followed a hyperbolic response to PAR, while in the Cjq plants it was linearly related to PAR up to the mean PAR ušed for growth. In this variant ^^20 seemed to change parallelly to changes in the mesophyll demand for CO2 caused by PAR.
Based on a 20-year fertilization experiment with wheat-maize double cropping system, the effects of different long-term fertilization treatments on leaf photosynthetic characteristics and grain yield in different winter wheat (Triticum aestivum L.) cultivars were studied in the growing seasons of 2000-2001 and 2001-2002. A total of nine fertilization treatments were implemented, i.e. no fertilizer (CK), N fertilizer (N), N and P fertilizers (NP), N and K fertilizers (NK), N, P, and K fertilizers (NPK), only organic manure (M), organic manure and N fertilizer (MN), organic manure and N and P fertilizers (MNP), and organic manure and N, P, and K fertilizers (MNPK). With the treatments of combined organic manure and inorganic fertilizers (TMI), net photosynthetic rate (PN), maximal activity of photosystem 2, PS2 (Fv/Fm), and chlorophyll content (SPAD value) of flag leaves and leaf area index (LAI) were much higher at the mid grain filling stage (20 or 23 d post anthesis, DPA), and exhibited slower declines at the late grain filling stage (30 DPA), compared with the treatments of only inorganic fertilizers (TI). The maximal canopy photosynthetic traits expressed as PN×LAI and SPAD×LAI at the mid grain filling stage were also higher in TMI than those in TI, which resulted in different grain yields in TMI and TI. Among the treatments of TMI or among the treatments of TI, both flag leaf and canopy photosynthetic abilities and yield levels increased with the supplement of inorganic nutrients (N, P, and K fertilizers), except for the treatment of NK. Under NK, soil contents of N and K increased while that of P decreased. Hence the unbalanced nutrients in soil from the improper input of nutrients in NK treatment were probably responsible for the reduced flag leaf and canopy photosynthetic characteristics and LAI, and for the fast declining of flag leaf photosynthetic traits during grain filling, resulting in the reduced yield of NK similar to the level of CK. and D. Jiang ... [et al.].
Three-years-old trees of Satsuma mandarin (Citrus unshiu [Mak.] Marc.) cv. Okitsu were exposed to O3 fumigation during long term (one year) in open-top chambers. As a result of the treatment, chlorophyll a fluorescence and gas exchange parameters were modified with respect to trees growing in O3-free conditions. Net photosynthetic rate and stomatal conductance decreased and intercellular CO2 concentration increased according to a reduction of the non-cyclic electron flow and a lower capacity to reduce the quinone pool. O3 also reduced the development of non-photochemical quenching preventing the dissipation of excess excitation energy and, therefore, generated several alterations in photosynthetic apparatus. All these effects were obtained in long-term exposure and higher O3 concentration. In O3 ambient conditions, the effects were minor. and A. Calatayud ... [et al.].
In order to investigate the effects of low irradiation (LI) on cucumber (Cucumis sativus L. cv. Jinyou 35) during a ripening stage, our experiment was carried out in a climate chamber. Two levels of PAR were set for plants: normal irradiation [NI, 600 μmol(photon) m-2 s-1] and low irradiation [LI, 100 μmol(photon) m-2 s-1], respectively. The experiments lasted for 9 d; then both groups of plants were transferred under NI to recover for 16 d. The plants showed severe chlorosis after the LI treatment. Chlorophyll (Chl) a, initial slope, photosynthetic rate at saturating irradiation (P max), light saturation point, maximal photochemical efficiency of PSII (Fv/Fm), electron transport rate of PSII (ETR), soluble protein content, and catalase (CAT) activity in cucumber leaves decreased under LI stress, while Chl b, carotenoids, light compensation point, nonphotochemical quenching (qN), superoxide dismutase (SOD), and malondialdehyde (MDA) exhibited an increasing trend under LI. After 16 d of recovery, values of P max, Fv/Fm, ETR, qN, SOD, CAT, MDA, and soluble protein were close to those of the control after one, three, and five days of the LI treatment, while those kept under LI for 7 and 9 d could not return to the control level. Therefore, 7 d of LI stress was a meteorological disaster index for LI in cucumber at the fruit stage., Z. Q. Yang, C. H. Yuan, W. Han, Y. X. Li, F. Xiao., and Obsahuje seznam literatury
Pepper is a thermophilous and heliophilic vegetable. In China, pepper is grown in greenhouse during winter and spring under lower temperature and irradiation. In this study, we investigated the effects of low temperature and low irradiance (LTLI) on the physiological characteristics and the expression of related genes in five pepper species, Capsicum annuum L. (CA), C. baccatum L. (CB), C. chinense Jacquin (CC), C. frutescens L. (CF), and C. pubescens Ruiz & Pavon (CP) in order to screen for greenhouse species that is resistant to such adverse conditions. We observed significant reductions not only in photosynthetic pigments and stomatal conductance but also in proline, total soluble sugar, enzyme activity, and root activity; disordered arrangements of leaf palisade and spongy tissues; and first rising and then falling expression of C-repeat binding factor (CBF3) and cold-regulated genes (CORc410). These results indicate that pepper is not resistant to LTLI. We also found that CP showed significantly higher photosynthetic activity, more proline and total soluble sugar, higher enzyme activity, higher root activity, higher CBF3 and CORc410 expression levels, more tightly packed leaf palisade and spongy tissues, and thicker bundle sheath than the other four species did under LTLI, while CF exhibited the lowest values for these indicators. It demonstrated significant differences in the ability to resist to LTLI among different species, with CP showing the strongest resistance, followed by CB. Therefore, we recommend the introduction of CP and CB to greenhouse cultivation to further screen for low temperature and low light-resistant pepper varieties to increase pepper production by strengthening intervariety hybridization., L. J. Ou, G. Wei, Z.Q. Zhang, X. Z. Dai, X. X. Zou., and Obsahuje bibliografii
The effects of four manganese (Mn) concentrations (1, 10, 50, and 100 g m-3 = Mn1, Mn10, Mn50, Mn100) in solution culture on growth variables were studied for seedlings of five deciduous broad-leaved trees with different successional characteristics and shoot development patterns in northern Japan. The five species were: Betula ermanii, Betula platyphylla var. japonica, and Alnus hirsuta (early-successional species with continuous leaf development), Ulmus davidiana var. japonica (mid-successional species with flush and continuous leaf development), and Acer mono (late-successional species with a flush type leaf development). In plants grown in the Mn environment for about 45 d, relative growth rate (RGR) decreased with increasing Mn supply. Between the 1 and 100 g(Mn) m-3, RGR decreased by 20 % for B. ermanii and B. platyphylla, by 40 % for A. hirsuta and A. mono, and by 80 % for U. davidiana. Specific leaf area (SLA) and leaf mass ratio (LMR) of all species were little affected by high Mn supply. In U. davidiana, however, there was a 67 % decrease in LMR in Mn100 plants. Leaf area ratio (LAR) was higher in early-successional species than in mid- and late-successional ones but differed little among Mn treatments within species, except for U. davidiana where LAR declined substantially with increased Mn supply. While LAR, which represents the relative size of assimilatory apparatus, was little affected, net photosynthetic rate (PN) saturated with radiant energy decreased with increasing Mn supply in all species. Thus PN was adversely affected by high accumulation of Mn in leaves, which resulted in an overall reduction in biomass production. However, the proportional allocation of photosynthates to the assimilatory apparatus was not affected by different Mn toxicity in hardwood tree seedlings. and M. Kitao, T. T. Lei, T. Koike.
Seedlings of four tree species (Bischofia javanica, Dracontomelon dao, Erythrina orientalis, and Pterocarpus indicus) were planted in flat and sloping grassland in plantation sites established in May 2002 in the La Mesa watershed, Philippines. Tree growth and net photosynthetic rate (PN) were monitored. The height, diameter at the root collar, and PN of the four species grown in the sloping grass site were larger than those of seedlings grown in the flat grass site. In addition, soil moisture contents in the sloping grass site were higher than those of the flat grass site. Growth of the four species was probably strongly associated with microenvironments (e.g. air temperature) in both tested sites. and S.-Y. Woo, D. K. Lee, Y.-K. Lee.