Apical Bud Growth Research Articles

Biological activity of crenatin, a glucoside from chestnut

Crenatin (3, 4, 5, tri-hydroxybenzyl alcohol, 4-glucoside) isolated from chestnut, was studied for its ability for improvement of rooting in the bean rooting test. Crenatin itself had a positive effect on number of roots. Moreover it enhanced the number of IAA-induced roots. In addition, a retardation of the apical bud growth was observed.

High temperature effects on apical bud morphology, dark respiration, and fixed growth of blue spruce

Night temperatures during bud elongation affected the fixed growth of preformed subapical buds of blue spruce (Piceapungens Engelm., 'Fat Albert' and 'Foxtail') but not apical bud growth. Plant volume decreased when nights were >14 °C, primarily because of reduced growth of each elongating subapical bud and not a decrease in number of growing points. Apical buds produced under a 30 °C day generally were broader and more flat topped, with more open, noncompressed bud scales than those produced under a 26 °C day. Night temperature had a greater effect on apical bud morphology than day temperature. The extent of bud break and growth during year n + 1 was inversely related to night temperature under which bud initiation and development occurred and directly related to the degree of apical bud normality noted during year n. 'Foxtail' had a greater degree of apical bud normality, a higher percentage of bud break, and retained its characteristic growth habit better than 'Fat Albert' following bud formation at high day and night temperatures. 'Foxtail' also had the lowest respiration rate and appeared to minimize detrimental effects of high temperatures through maintenance of a relatively low respiratory Q10 value (increase in respiration rate for each 10 °C increase in temperature) over a wide temperature range.

Functions of microtubules in the Saccharomyces cerevisiae cell cycle.

We used the inhibitor nocodazole in conjunction with immunofluorescence and electron microscopy to investigate microtubule function in the yeast cell cycle. Under appropriate conditions, this drug produced a rapid and essentially complete disassembly of cytoplasmic and intranuclear microtubules, accompanied by a rapid and essentially complete block of cellular and nuclear division. These effects were similar to, but more profound than, the effects of the related drug methyl benzimidazole carbamate (MBC). In the nocodazole-treated cells, the selection of nonrandom budding sites, the formation of chitin rings and rings of 10-nm filaments at those sites, bud emergence, differential bud enlargement, and apical bud growth appeared to proceed normally, and the intracellular distribution of actin was not detectably perturbed. Thus, the cytoplasmic microtubules are apparently not essential for the establishment of cell polarity and the localization of cell-surface growth. In contrast, nocodazole profoundly affected the behavior of the nucleus. Although spindle-pole bodies (SPBs) could duplicate in the absence of microtubules, SPB separation was blocked. Moreover, complete spindles present at the beginning of drug treatment appeared to collapse, drawing the opposed SPBs and associated nuclear envelope close together. Nuclei did not migrate to the mother-bud necks in nocodazole-treated cells, although nuclei that had reached the necks before drug treatment remained there. Moreover, the double SPBs in arrested cells were often not oriented toward the budding sites, in contrast to the situation in normal cells. Thus, microtubules (cytoplasmic, intranuclear, or both) appear to be necessary for the migration and proper orientation of the nucleus, as well as for SPB separation, spindle function, and nuclear division.

Manipulation of the polyamine content and senescence of apical buds of G2 peas

The effect of various treatments on the apical senescence and polyamine content of apical buds of G2 peas was analysed. Defruiting prevented senescence and increased bud size and polyamine content. Exogenous applications of GA20 enhanced bud size and spermidine concentration. Applied spermidine had a slight effect on spermidine level but did not delay senescence. ACC strongly induced adecrease in bud size and, at 10mM, apical senescence. This was accompanied by a steady decline in the level of all polyamines though their concentration remained constant until 10 mM ACC, where a drop was noted. Spermidine in the presence of ACC modulated the effect of ACC on the bud size white returning the internal polyamine content to control levels. AVG, an inhibitor of ACC synthesis produced pronounced increases in putrescine though no apparent effect on apical bud growth. Polyamine synthesis inhibitors were without effect on growth or internal polyamine content. The internal polyamine content appeared to correlate with apical bud size and vigor but did not show any consistent relationship to apical bud senescence.

Effect of Abscisic Acid and Other Plant Hormones on Growth of Apical and Lateral Buds of Seedlings

AbstractThe effect of abscisic acid (AbA) on the growth of lateral and apical buds was studied in seedlings of Pisum sativum and some other species. The hormone was applied in three different ways: 1) directly to the lateral bud on the second node of decapitated pea seedlings as 5 μI droplets in an ethanolic solution; 2) to the cut surface of decapitated seedlings: 3) to the apical bud of intact plants.AbA directly applied in amounts of 5 to 0.1 μg to the lateral bud of the second node of decapitated seedlings had a strong inhibitory effect on the bud. Application to the cut surface of seedlings decapitated about 5 mm above the second node resulted in slight inhibition of the lateral bud on the second node and in growth promotion of the bud on the first node. When AbA at 10 to 0.1 μg was applied to the apical bud of intact seedlings, the growth of this bud was inhibited but the lateral buds grew out.It is concluded that the release of the lateral buds from apícal dominance is the result of the inhibitory effect of AbA on growth of the apical bud and of low transport of AbA. This conclusion is supported by application of GA3 and IAA, individually and each combined with AbA.