Objective To study the water-sensitive reflectance spectra bands of Phyllostachys violascens canopy leaves and screen the suitable reflectance spectral indexes of leaf water content, aiming at ...nondestructive estimation of leaf water content.Method The present study investigated the canopy leaf reflectance spectrum characteristics of Ph. violascens during isolated natural water loss process. The correlation between reflectance spectral indexes and leaf water indicators were calculated and analyzed. The regression equation between leaf relative water content (RWC) and reflectance spectral indexes were also calculated.Result The leaf water content and its spectral reflectance were negatively correlated in the near-infrared region. The spectral reflectance sensitivity analysis showed that the spectral reflectance in 1 400~1 600 nm and 1 800~2 000 nm was significantly changed with the decrease of the leaf water content. Correlation analysis and regression model between different spectral reflectance indexes
Objective A total of 50 healthy clusters about 150 needles were sampled from 40 Larix olgensis trees at the age of 10 to 40 years in Jingouling Forest Farm of Wangqing Forestry Bureau, Jilin ...Province, for the establishment of leaf area regression models and estimation of specific leaf area.Method The needle area, needle length, needle width and needle perimeter were obtained using WinSEEDLE software, and the needles were dried to a constant weight to obtain the needle dry mass. The unitary, binary and ternary regression models were established with needle length (L), needle width (W), needle perimeter (P) and needle dry mass (M) as independent variables and needle area (LA) as a dependent variable. Linear, exponential and power function models were used for fitting. The mean error, total relative error, mean system error, mean prediction error and root mean square error were used to verify the errors and evaluate the goodness of model fitting. The variance of arithmetic average method, ratio estimation me
Objective Illustrating the aphid gall number and distribution of Schlechtendalia chinensis under two inoculation methods (natural migration and artificial aphid bags) and their effects on the foliage ...growth of host Rhus chinensis.Method The sample sites and host plants were selected by random group setting in the fields which inoculated by natural migration and hanging aphid bags. The growth indexes and traits of the galls and their host trees were measured or counted. The host plant growths effected by aphid galls were analyzed using variance analysis.Result No significant difference was observed in the gall numbers per tree of the two inoculation methods. However, the average of total gall volume per compound leaf on the trees inoculated by aphid bags was 170.92±14.85 cm3 which was almost twice the average gall volume (85.82±9.40 cm3) on the trees inoculated by natural migration, and the total area of leaflets per compound leaf on the trees inoculated by artificial pouch was 616.26±32.73 cm2 which was
Leaf anatomical characters of twelve species from the genus Cyperus, a genus known to contain species with both C3 and C4 plants, have been investigated. We investigated and established the ...usefulness of all‐inclusive functional leaf anatomical characters for identifying the photosynthetic pathways of these species. The species investigated were C. articulatus L., C. compressus L., C. difformis L., C. dilatatus Schum. & Thonn., C. distans L., C. esculentus L., C. haspan L., C. imbricatus Retz., C. iria L., C. rotundus L., C. sphacelatus Rottb. and C. tenuiculmis (Boeck.) Hooper, collected from locations in southwestern Nigeria. Standard anatomical procedures for examining epidermal and cross sections of leaves were employed. Our data suggested that a combination of characters, such as the occurrence of Kranz tissue, maximum cell distant count, maximum lateral cell count, interveinal distance, and to some extent leaf and mesophyll thickness, provide a reliable basis for the assessment of the photosynthetic pathways of the investigated species as compared to the isolated characters used previously. The study indicate that C. difformis and C. haspan are C3 species while the rest follow the C4 photosynthetic pathway. A salient feature of this study is the identification of C. dilatatus as belonging to the C4 group.
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The authors aimed to estimate the area of the leaf blade of different plants based on linear and dry weight measures, calibrated with the free software ImageJ. The leaves of cotton plants (Gossypium ...hirsutum L) var. IMACD 6001, cashew (Anacardium occidentale L) var. FAGA 10, soybean (Glycine max L) var. M-SOY 7639RR, and corn (Zea mays L) var. Penta TL were collected from the lower third, middle and top in different phenological phases. It was found that images with a resolution of at least 7.2 megapixels can be used to estimate the actual leaf blade area, processed with the ImageJ software till 324cm^sup 2^. They observed a good agreement in the estimation of the leaf blade area based on linear and dry mass measures and, therefore, it is recommended to estimate leaf area leaves with damaged pieces or measures from several samples of leaves collected at the field based on the dry weight of the leaves, as it is operationally viable.
In plants, reactive oxygen species (ROS) associated with the response to pathogen attack are generated by NADPH oxidases or apoplastic peroxidases. Antisense expression of a heterologous French bean ...(Phaseolus vulgaris) peroxidase (FBP1) cDNA in Arabidopsis thaliana was previously shown to diminish the expression of two Arabidopsis peroxidases (peroxidase 33 PRX33 and PRX34), block the oxidative burst in response to a fungal elicitor, and cause enhanced susceptibility to a broad range of fungal and bacterial pathogens. Here we show that mature leaves of T-DNA insertion lines with diminished expression of PRX33 and PRX34 exhibit reduced ROS and callose deposition in response to microbeassociated molecular patterns (MAMPs), including the synthetic peptides Flg22 and Elf26 corresponding to bacterial flagellili and elongation factor Tu, respectively. PRX33 and PRX34 knockdown lines also exhibited diminished activation of Flg22-activated genes after Flg22 treatment. These MAMP-activated genes were also downregulated in unchallenged leaves of the peroxidase knockdown lines, suggesting that a low level of apoplastic ROS production may be required to preprime basal resistance. Finally, the PRX33 knockdown line is more susceptible to Pseudomonas syringae than wild-type plants. In aggregate, these data demonstrate that the peroxidase-dependent oxidative burst plays an important role in Arabidopsis basal resistance mediated by the recognition of MAMPs.
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Exosomes are extracellular vesicles (EVs) that play a central role in intercellular signaling in mammals by transporting proteins and small RNAs. Plants are also known to produce EVs, particularly in ...response to pathogen infection. The contents of plant EVs have not been analyzed, however, and their function is unknown. Here, we describe a method for purifying EVs from the apoplastic fluids of Arabidopsis (Arabidopsis thaliana) leaves. Proteomic analyses of these EVs revealed that they are highly enriched in proteins involved in biotic and abiotic stress responses. Consistent with this finding, EV secretion was enhanced in plants infected with Pseudomonas syringae and in response to treatment with salicylic acid. These findings suggest that EVs may represent an important component of plant immune responses.
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Leaf senescence is not a passive degenerative process; it represents a process of nutrient relocation, in which materials are salvaged for growth at a later stage or to produce the next generation. ...Leaf senescence is regulated by various factors, such as darkness, stress, aging, and phytohormones. Strigolactone is a recently identified phytohormone, and it has multiple functions in plant development, including repression of branching. Although strigolactone is implicated in the regulation of leaf senescence, little is known about its molecular mechanism of action. In this study, strigolactone biosynthesis mutant strains of Arabidopsis (Arabidopsis thaliana) showed a delayed senescence phenotype during dark incubation. The strigolactone biosynthesis genesMORE AXIALLY GROWTH3 (MAX3)andMAX4were drastically induced during dark incubation and treatment with the senescence-promoting phytohormone ethylene, suggesting that strigolactone is synthesized in the leaf during leaf senescence. This hypothesis was confirmed by a grafting experiment usingmax4as the stock and Columbia-0 as the scion, in which the leaves from the Columbia-0 scion senesced earlier thanmax4stock leaves. Dark incubation induced the synthesis of ethylene independent of strigolactone. Strigolactone biosynthesis mutants showed a delayed senescence phenotype during ethylene treatment in the light. Furthermore, leaf senescence was strongly accelerated by the application of strigolactone in the presence of ethylene and not by strigolactone alone. These observations suggest that strigolactone promotes leaf senescence by enhancing the action of ethylene. Thus, dark-induced senescence is regulated by a two-step mechanism: induction of ethylene synthesis and consequent induction of strigolactone synthesis in the leaf.
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