1,720,976 research outputs found
Proteolysis in embryogenesis of Phaseolus coccineus: possible control by ionic strength
No full textThe presence of both alkaline and acidic proteinase activities has been evidenced in the suspensor of 11 mm long seeds of Phaseolus coccineus.
The acidic activity is mainly localized in the basal giant cells and is regulated by low molecular weight thermostable inhibitors. There is evidence from in vitro experiments that ionic strength may regulate the activity
Transcriptomic changes induced by an acute ozone stress in sensitive and tolerant Populus spp
No full textAbscisic acid levels and cell structure in single seed tissues of shedding affected fruits of Malus domestica Borkh
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
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
An Acute O3 Stress Induces Changes in Chromatin Organization and in Functional Activity of Nuclei and Nucleoli in Sensitive Poplar Clones Leaves
No full textOzone Induces a HR-like Response in the O3-Sensitive Populus Deltoides x Maximowiczii Eridano Clone
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