Search results for "abscission"
showing 7 items of 17 documents
Investigations on the content indole-3-acetic spruce needles of healthy and damaged trees of various sites
1993
Summary Surveys were made on the concentration of indole-3-acetic acid (IAA) in spruce trees of various sites. The concentrations of the hormone were specified with a radioimmunoassay after the needle extract had been purified in several steps. The content of IAA in needles of damaged trees was distinctly lower than the content in needles of healthy trees. Another feature was the annual rythm of the IAA content with the maximum of concentration in June. A distinct diurnal course with highest level of concentration during the early afternoon hours was also observed. The diurnal rhythm of the damaged trees was clearly lower. The supposition is that the lower IAA content is responsible for a p…
NUTRITIONAL AND HORMONAL FACTORS AFFECTING FRUIT SET IN AVOCADO (Persea americana Mill.)
2017
Under favourable conditions, the avocado sets more fruits than the tree is able to bring to maturity, so that the plant adjusts, during the early stages of development, its ability to nourish them by modifying their number, that is, causing the fruit drop of those who can not maintain their growth rate. Accordingly, carbohydrate availability could be a key factor in the physiological abscission of these fruits. Since this species presents dichogamy, the abscission of fruits has also been attributed to the absence of pollination, but at the same time it has been related to failures in seed development, embryo abortion, seed coat collapse, and with the effect of an environmental stress, espec…
Transcriptomic Analysis of the Pistacia vera (L.) Fruits Enable the Identification of Genes and Hormone-Related Gene Linked to Inflorescence Bud Absc…
2021
Pistacia vera (L.) is an alternate bearing species. The tree produces axillary inflorescence buds every year. Still, they abscise in “ON” overloaded shoots, causing a limited production in the following “OFF” year, causing a significant and unfavorable production fluctuation. In this work, we carried out de novo discovery and transcriptomic analysis in fruits of “ON” and “OFF” shoots of the cultivar Bianca. We also investigated whether the fruit signaling pathway and hormone biosynthesis directly or indirectly linked to the premature fall of the inflorescence buds causing alternate bearing. We identified 1536 differentially expressed genes (DE…
Morphological and anatomical observations of abnormal somatic embryos from anther cultures of Citrus reticulata
2010
A morphological and anatomical study of regenerants obtained from mandarin anther culture was carried out. Beside morphologically normal somatic embryos, abnormal structures were originated in the course of somatic embryogenesis. Anatomical anomalies can be found at several growth stages, causing the formation of slender stems, stubby structures, non-functional leaves. When too long, some structures are subject to shedding, with the formation of various abscission zones. Most of them are subject to degeneration, although many are capable of further, localized, morphogenesis. A thorough knowledge of morphology and anatomy of normal and abnormal regenerants could make possible to select and s…
Grapevine fruit set: Physiology of the abscission zone
2000
Effects of ethylene and of 'anti-ethylene' compounds on the floral pedicel abscission zone in grapevines were analysed via a laboratory model consisting of isolated flowers held in Petri dishes. Our model permitted precise determination of abscission and enabled us to test a range of physiologically-active compounds including ethylene precursors, and antagonists of ethylene action. For example, a precursor of ethylene, 1-aminocyclopropane-l-carboxylic acid, had the same effect as ethylene in promoting abscission. Conversely, an inhibition of ethylene action by silver thiosulfate or an inhibition of ethylene synthesis by amino-oxyacetic acid both strongly inhibited abscission zone function. …
Absence of the endo-beta-1,4-glucanases Cel1 and Cel2 reduces susceptibility to Botrytis cinerea in tomato.
2007
Cel1 and Cel2 are members of the tomato (Solanum lycopersicum Mill) endo-beta-1,4-glucanase (EGase) family that may play a role in fruit ripening and organ abscission. This work demonstrates that Cel1 protein is present in other vegetative tissues and accumulates during leaf development. We recently reported the downregulation of both the Cel1 mRNA and protein upon fungal infection, suggesting the involvement of EGases in plant-pathogen interactions. This hypothesis was confirmed by assessing the resistance to Botrytis cinerea infection of transgenic plants expressing both genes in an antisense orientation (Anti-Cel1, Anti-Cel2 and Anti-Cel1-Cel2). The Anti-Cel1-Cel2 plants showed enhanced …
Zur Bewertung der Blattdornen vonHalimodendron halodendron (Fabaceae)
1979
Halimodendron halodendron is a spiny shrub of north-western Asia. The spines are formed by the rachises of the paripinnate leaves. After abscission of pinnae the rigid rachises remain for several years. In culture these rachis spines do not develop fully.