1,721,026 research outputs found
Mezzi chimici di controllo del germogliamento del tubero di patata (Solanum tuberosum L.)
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Are xylem radial development and hydraulic conductivity in downwardly-growing grapevine shoots influenced by perturbed auxin metabolism? RID A-6610-2010
No full textDownwardly-growing grapevine shoots have smaller and more frequent vessels than upwardly-growing ones and, as a consequence, a lower hydraulic conductivity. Here, grapevine (Vitis vinifera L.) shoot growth orientation was manipulated to test whether downward shoot orientation negatively affects vessel growth in the apex via a shortage of water and nutrients. The orientation of the central vine shoot portion was inverted by two consecutive 135degrees bends, resulting in double-bent N-shaped vines; the central downward shoot portion was of different lengths in the experimental treatments to induce increasing reductions of shoot conductivity. These treatments reduced shoot conductivity and water flow, but had no effects on vessel development and frequency in the apex. In a second experiment, auxin concentration was assessed in shoots of upwardly- and downwardly-growing plants. IAA concentration at the apical internodes was higher in downwardly-oriented shoots than in shoots growing upwards. In addition, a higher density and a lower vessel diameter were observed in the lower, than the upper side, of the downwardly-oriented shoot, suggesting increased accumulation of auxin in the lower side. These results suggest that the downward orientation induces accumulation of auxin in the apex, which in turn affects the density and the size of the xylem vessels, causing reduction of hydraulic conductivity
The effects of (S)-(+)-carvone treatments on seed potato tuber dormancy and sprouting
Full text linkPotato seed tubers may suffer from premature sprouting during storage, thus limiting their suitability for cultivation. Commonly used sprout suppressant treatments negatively affect bud viability and therefore a reliable method to inhibit bud development must still be found for seed tubers. The monoterpene carvone ((S)-(+)-carvone) was tested in small scale experiments. The vapour of this compound fully inhibited bud growth of tubers cv. Monalisa stored at 23 degrees C without affecting bud viability throughout 6 months of treatment. The most effective range of carvone vapour concentrations was between 0.34 and 1.06 mu mol mol(-1). With these qualities we can expect carvene to become a suitable sprout suppressant for seed tubers
Cytological and hormonal investigations on programmed cell death of the nucellus of Sechium edule Sw
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Strigolactone may interact with gibberellin to control apical dominance in pea (Pisum sativum)
Full text linkThe role of strigolactones as plant growth regulators
has been demonstrated through research on biosynthesis
and signaling mutant plants and through the use of
GR24, a synthetic analog of this class of molecules. Strigolactone
mutants show a bushy phenotype and GR24 application
inhibits the growth of axillary buds in these mutants,
thus restoring the phenotype of a wild plant, which is characterized
by a stronger apical dominance. In this work, we
tested the effectiveness of this chemical on pea (Pisum sativum)
plants following apex removal, which disrupts apical
dominance and leads to axillary bud outgrowth. Moreover,
we searched for relationships between the response to the
strigolactone and gibberellin metabolism by applying GR24
to both climbing and dwarf peas, the latters being mutants
for gibberellin biosynthesis. The results suggest that the
endogenous level of the bioactive gibberellin GA1 might
modulate the response of decapitated pea plants to GR24, by
changing bud sensitivity to the applied strigolactone
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