1,720,968 research outputs found
Abscisic acid levels and seed structure in abscision affected fruits of Malus domestica Borkh
No full textDynamics of Pollen Grain Germination in Two Cultivars of Malus domestica: the Influence of Actinomycin D on Fresh and Stored Pollen Grains
No full textThe pattern of germination has been detected in the presence or in the absence of Actinomycin D (AmD) in fresh and stored binucleate pollen grains of' Golden Delicious' (GD) and' Starkrimson' (S). Pollen tube growth consisted of two distinct phases, autotrophic and heterotrophic, in both fresh and stored pollen grains. The pollens of the two cultivars differ: (i) in the length of the first phase, being 3 h in GD and 2 h in S, and (ii) in the response to storage. As far as the response to storage is concerned the cultivar S seems to be more
damaged than GD when the storage effect is evaluated as the first phase length; less damaged than GD when the effect is expressed as tube length
Transcriptomic changes induced by an acute ozone stress in sensitive and tolerant Populus spp
No full textAn Acute O3 Stress Induces Changes in Chromatin Organization and in Functional Activity of Nuclei and Nucleoli in Sensitive Poplar Clones Leaves
No full textViability of stored pollen grains of malus domestica borkh as evaluated by the incorporation of labelled nucleic acid precursors
No full textViability of stored pollen grains of Malus domestica Borkh, cultivars "Golden delicious" and "Starkrimson" is expressed as: 1) percentage of labelled generative and vegetative cells after feeding with 3H-thymidine and 3H-uridine; 2) percentage of germinated pollen grains. The ability to incorporate nucleic acid precursors ecreases during storage; the vegetative cytoplasm response to storage is slower than the nuclear response, in respect to both 3H-thymidine and 3H-uridine incorporation. The germination ability is not influenced by the investigated storage. No relationship between the capacity of incorporating nucleic acid precursors and pollen grains germination is therefore detectable
Stress induced morphogenic responses at different As concentrations in Pteris vittata roots
No full textOzone damage and tolerance in leaves of two poplar genotypes
No full textThe effects induced by an acute ozone exposure were investigated in two poplar hybrids differentially O3 susceptible in terms of leaf injuries: Populus deltoides x maximowiczii, Eridano clone and Populus x euramericana, I-214 clone, the sensitive and the tolerant respectively. Both the leaf anatomy and the responses induced by ozone in the leaves were analysed, using a cyto-histochemical approach. Morphoanatomical characters, such as amphistomatous lamina, higher stomatal density and relaxed mesophyll cell packing (evaluated by the palisadeness coeffi cient), observed in the sensitive clone leaves, may favour a greater O3 uptake in the apoplast and increase the cumulative dose of pollutant per mesophyll cell, with respect to tolerant clone leaves. Mesophyll cells of sensitive plants were the main targets for O3. After an acute ozone treatment, the palisade parenchyma cells showed a decrease in chloroplast number and size, resulting best suited both to perceive the stress by O3 or reactive oxygen species (ROS) and to activate several signal transduction pathways, in relation to their morphological, physiological and functional properties predisposing an efficient cell communication, signalling and stimuli sensing. The quick and well localized pattern of cell death induced by O3 in sensitive poplar leaves was accompanied by some hallmarks of programmed cell death (PCD): nuclear shrinkage, chromatin condensation and cell wall collapse
Ozone Induces a HR-like Response in the O3-Sensitive Populus Deltoides x Maximowiczii Eridano Clone
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