The recognition of aquatic organisms plays a crucial role in the monitoring of the pollution and for the adoption of rapid preventive actions. A compact microscopic optical imaging system is proposed in order to acquire and treat the multibands fluorescence of several pigments in phytoplankton organisms. Two algorithms for automatic recognition of phytoplankton were proposed with a minimum number of calibration parameters. The first algorithm provides a morphological recognition based on "watershed" segmentation and Fourier descriptors, while the second one builds fluorescence pigment images by "k-means" partition of intensity ratios. The operation of these algorithms was illustrated by the study of two different organisms: a cyanobacteria (Dolichospermum sp.) and an alga (Cladophora sp.). The family and the genus of these organisms were then classified into a database which is independent of the size, the orientation and the position of the specimens in the images., M. Lauffer, F. Genty, S. Margueron, J. L. Collette., and Obsahuje bibliografii
For Tunisian olive tree orchards, nitrogen deficiency is an important nutritional problem, in addition to the availability of water. Establishment of relationships between nutrients such as nitrogen and ecophysiological parameters is a promising method to manage fertilisation at orchard level. Therefore, a nitrogen stress experiment with one-year-old olive trees (Olea europaea L. 'Koroneiki' and 'Meski') was conducted with trees respectively subjected to four nitrogen supply regimes (23.96 meq l-1, 9.58 meq l-1, 4.79 meq l-1 and 0 meq l-1 NO3-).
The current paper focuses on the use of the SPAD-502 portable chlorophyll (Chl) meter, a nondestructive method for fertilisation management under nitrogen stress conditions of olive trees. Maximum net photosynthetic assimilation rates, chlorophyll fluorescence parameters and the SPAD Chl index were therefore measured simultaneously and the Chl and nitrogen content of the leaves were analysed. Significant correlations were established in the olive tree leaves between SPAD-502 readings on the one hand and Chl content, nitrogen content, photosynthetic assimilation rate, and Chl fluorescence parameters (ΦPSII and ETR) on the other hand. and O. Boussadia ... [et al.].
Different pigments often occur together and affect photosynthetic characteristics of the respective leaf portions. In this study, photosynthetic activity in variegated leaves of five cultivars of the ornamental and medicinal plant, Coleus × hybridus hort., was estimated by image analysis and point data measurements of major chlorophyll (Chl) fluorescence parameters and related to the amount of photosynthetic pigments measured with a Chl meter or spectrophotometrically in leaf extracts. Significant differences in Chl and carotenoid (Car) contents were noticed among differentially pigmented sectors of a leaf and among the cultivars. Although the higher Chl concentration was noticed in purple parts compared to green parts of the leaves, the values of minimal and maximal fluorescence yield at the dark- and light-adapted state (F0, Fm, F0', Fm', respectively) were a little lower than those in the green sectors, indicating photoprotective effects provided by anthocyanins and Car, more abundant in the red parts. The lowest Chl and Car content was detected in creamy-yellow and pink sectors and this contributed to low F0, Fm, and Fm', maximal quantum yield of PSII photochemistry, and nonphotochemical and photochemical quenching but high PSII maximum efficiency and effective quantum yield of PSII photochemistry. Both methods of Chl fluorescence analysis revealed heterogeneity in capture, transfer, and dissipation of excitation energy but Chl fluorescence imaging was more suitable in examining very narrow pigmented leaf areas., M. Borek, R. Bączek-Kwinta, M. Rapacz., and Seznam literatury
An early senescence (es) mutant of rice Oryza sativa L. with progressing death of most of leaves before heading stage was identified in the field in Hainan province. After tillering stage, the brown striations were found in the base of green leaves randomly, and then expanded to whole leaves. No fungi, bacteria, and viruses were detected in the brown striations suggesting that it was a genetic mutant. The ultrastructure of leaf cells at the site of brown striations showed breakdown of chloroplast thylakoid membrane structures and other organelles, and condensation of the cytoplasm at severe senescence stage. The photosynthetic activity and chlorophyll (Chl) contents decreased irreversibly along with leaf senescence process. and L. F. Wang, Y. Y. Chen.
The present study revealed that Ginkgo biloba and Platanus occidentalis, the most abundant roadside trees in Seoul, grown under polluted environmental conditions, displayed lower contents of total chlorophyll (Chl), carotenoids (Car), and ascorbic acid (AsA) compared to the trees grown under clean conditions. The reduction in Chl, Car, and AsA contents was 59, 53, and 50%, respectively, in G. biloba, contrary to 26, 23, and 24%, respectively, in P. occidentalis. Furthermore, relative ion leakage and leaf temperature was higher in the trees grown under polluted conditions than in those grown under clean conditions. The increase in relative ion leakage and leaf temperature was 58 and 3% for G. biloba and 17 and 4% for P. occidentalis, respectively. Our results, therefore, highlighted the negative impact of urban environmental pollution on the physiological and biochemical parameters in roadside trees., H. N. You, S. Y. Woo, C. R. Park., and Seznam literatury
This study aimed to determine the effects of plant growth-promoting rhizobacteria Bacillus subtilis JS on the growth and physiological changes of Populus euramericana and Populus deltoides x P. nigra. Poplar seedlings were treated with B. subtilis JS and their growth was monitored for up to 120 d. Three different types of treatments [control, B1 (B. subtilis:double-distilled water, 1:100, v/v), and B2 (1:50)] were established. B. subtilis JS enhanced seedling height by 62% and total biomass by 37% after 120 d. Physiologically, the photosynthetic rate increased by 54%, and the total chlorophyll (Chl) content, foliage nitrogen and phosphate content were significantly higher after treatment with B2 than that of the control. These results suggest that the total Chl content is directly related to not only the photosynthetic capacity of the foliage but also to the nitrogen content, indicating that the strain JS may promote the growth of poplar., J. H. Jang, S.-H. Kim, I. Khaine, M. J. Kwak, H. K. Lee, T. Y. Lee, W. Y. Lee, S. Y. Woo., and Obsahuje bibliografii
Macroalgae must be able to survive in conditions of different light intensities with no damage to their physiological performance or vital processes. Irradiance can stimulate the biosynthesis of certain photoprotective compounds of biotechnological interest, such as pigments and proteins. Pterocladiella capillacea is a shade-grown alga, which play a role key in the balance of marine ecosystems. In addition, it is considered one of the best sources of bacteriological agar and agarose with a wide pharmacological potential. In order to evaluate the photosensitivity in P. capillacea under 60 (control) and moderate light intensity of 300 μmol(photon) m-2 s-1, photosynthetic performance and chemical composition were assessed. P. capillacea showed photosensitivity without evidence of photodamage. The results indicate the possibility to increase a growth rate and probably infer productivity in long-term cultivation by stimulation at moderate light intensity. Increasing photosynthetic pigment and protein contents were also observed under medium light, an interesting result for functional ingredient approaches., T. B. Harb, A. Nardelli, F. Chow., and Obsahuje bibliografii
LED lamps with various combinations of red (R) and blue (B) wavelengths were used to supplement sunlight for the growth of a heat-resistant (HR) and heat-sensitive (HS) recombinant inbred lines (RIL) of lettuce. The RB-LED ratios were 100R:0B (0B), 92R:8B (8B), 84R:16B (16B), and 76R:24B (24B) with an equal PPFD of 100 μmol m-2 s-1. The greatest leaf expansion rates were observed at 8B for both genotypes. All HR-RILs had similar values of growth parameters and specific leaf area (SLA). However, higher values of growth parameters were observed in HS-RIL with 0B, 8B, and 16B than that under 24B and sunlight. Furthermore, HS-RIL had higher SLA under 0B compared to other conditions. Photosynthetic light-use efficiency and maximal oxygen evolution rate were the lowest under 8B for both genotypes. The quality of LED lighting, if provided, seemed to implicate genotype dependence, probably as a result of their different sensitivities to heat stress., T. W. Choong, J. He, L. Qin, S. K. Lee., and Obsahuje bibliografii
The source-sink relationship is one of major determinants of plant performance. The influence of reproductive sink demand on light-saturated photosynthesis (Pmax), dark respiration (RD), stomatal conductance (gs), intrinsic water-use efficiency (WUEi), contents of soluble sugar (SSC), nitrogen, carbon, and photosynthetic pigments was examined in blueberry (Vaccinium corymbosum L. cv. ‘Brigitta’) during the final stage of rapid fruit growth. Measurements were performed three times per day on developed, sun-exposed leaves of girdled shoots with 0.1, 1, and 10 fruit per leaf (0.1F:L, 1F:L, and 10F:L, respectively) and nongirdled shoots bearing one fruit per leaf (NG). Girdling and lower fruit amount induced lower Pmax, gs, N, and total chlorophyll (Chl) and higher WUEi, SSC, RD, Chl a/b ratio and carotenoids-to-chlorophylls ratio (Car/Chl) for the 1F:L and 0.1F:L treatments. The impact of girdling was counterbalanced by 10F:L, with NG and 10F:L having similar values. Variables other than Pmax, RD, gs, WUEi, and SSC were unaffected throughout the course of the day. Pmax and gs decreased during the course of the day, but gs decreased more than Pmax in the afternoon, while WUEi was increasing in almost all treatments. SSC increased from the morning until afternoon, whereas RD peaked at noon regardless of the treatment. Generally, Pmax was closely and negatively correlated to SSC, indicating that sugar-sensing mechanisms played an important role in regulation of blueberry leaf photosynthesis. With respect to treatments, Pmax and N content were positively related, while RD was not associated to substrate availability. The enhanced Car/Chl ratio showed a higher photoprotection under the lower sink demand. Changes in the source-sink relationship in 'Brigitta' blueberry led to a rearrangement of physiological and structural leaf traits which allowed adjusting the daily balance between carbon assimilation and absorbed light energy., E. Jorquera-Fontena, M. Alberdi, M. Reyes-Díaz, N. Franck., and Obsahuje bibliografii
Ramie (Boehmeria nivea L.) is an important crop that serves as fine fiber material, high protein feedstuff, and valuable herbal medicine in China. However, increasing salinity in soil limits the productivity. We investigated in a greenhouse experiment responses to salinity in two ramie cultivars, Chuanzhu-12 (salt-tolerant cultivar, ST) and Xiangzhu-2 (salt-sensitive cultivar, SS), to elucidate the salt tolerance mechanism of this species. Salinity stress substantially reduced both chlorophyll and carotenoid contents. In addition, net photosynthesis, transpiration rate, stomatal conductance, intercellular CO2 concentration, and the ratio of intercellular CO2 to ambient CO2 were affected, less in ST. Nevertheless, salinity stress markedly improved water use efficiency and intrinsic water use efficiency in both species. Moreover, relative water contents, soluble proteins, and catalase activity were substantially impaired, while proline accumulation and superoxide dismutase activity were enhanced substantially, more in ST. Furthermore, noteworthy increase in peroxidase activity and decrease in malondialdehyde content was recorded in ST, whereas, in SS, these attributes changed conversely. Overall, the cultivar ST exhibited salt tolerance due to its higher photosynthetic capacity, chlorophyll content, antioxidative enzyme activity, and nonenzymatic antioxidants, as well as reduced lipid peroxidation and maintenance of the tissue water content. This revealed the salt tolerance mechanism of ramie plants for adaptation to salt affected soil., C.-J. Huang, G. Wei, Y.-C. Jie , J.-J. Xu, S.-Y. Zhao, L.-C. Wang, S. A. Anjum., and Obsahuje seznam literatury