Effect of the Form and Concentration of N on the Growth and Mineral Composition of Olive Seedlings

Abstract

The influence of three salts (KN03, NH4N03 and (NH4>2S04) in different concentrations, on the growth and mineral composition of olive seedlings cultured in vitra and in greenhouse conditions, was studied. The best growth was obtained in in vitra culture through the applications of NH4N03, in concentrations of 10 and 20 mM of N. Addition of (NH4)2S04 clearly damaged the seedlings and increased the contents of S in the seedlings' tissues. AH the treatments led to a direct relationship between concel'ltration of N in the medium and N in the seedling tissues, however the N-increases were lowest for KN03 and highest for ammonium applications, especiaHy for NH4N03. In greenhouse conditions aH the N-treatments significantly increased the growth of the seedlings but no significant differences between N-salts were observed except for (NH4)2S04 at the highest concentration. Treatment with (NH4)2S04 did not induce any symptom of toxicity in the seedlings, in contrast to the behaviour of in vitro seedlings. The treatments did not cause significant changes in the mineral composition of the seedling tissues. These circumstances were related to the fact that an oxidation process (nitrification) was produced from N-NH4 to N-N03 in the nutritive solutions in the containers.

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“…In vitro olive embryo germination has become a powerful tool to overcome the problems derived from the low ability of the seeds to germinate in the field Sarmiento et al, 1994;Acebedo et al, 1997), and thus to speed up the process of obtaining new olive plants for olive breeding programs.…”

“…By means of in vitro olive zygotic embryo germination with an appropriate nitrogen supply, a reduction of the germination time, a germination percentage close to 100% and an increase of the growth rate of seedlings has been achieved (García et al, 1994;Sarmiento et al, 1994;Acebedo et al, 1997). Nevertheless, olive germinated in vitro still shows a limited proliferation rate due mainly to a lack of secondary shoot production; this technique needs further improvement.…”

Influence of the Mycorrhizal Glomus Intraradices on the Development of in Vitro Raised Olive Seedlings During Acclimation Phase

“…By in vitro culture of isolated mature olive embryos very high germination percentages have been obtained (Troncoso et al, 1991;Voyiatzis and Pritsa, 1994;Voyiatzis, 1995) in few days, even reaching 100% (Acebedo et al, 1997) and by using appropriate nitrogen forms and concentrations (García et al, 1994;Sarmiento et al, 1994) and sugar (García et al, 2002) a high in vitro growth of the seedlings was obtained. The use of a suitable substratum (Rugini, 1984), nutritive solutions (García et al, 1999) and photoperiod (Alvarado, 1994) during the hardening phase also increases the plant development.…”

In Vitro Selection of Salt-Tolerant Olive Clones

“…Thus, removal of the stony endocarp accelerates germination, and enhances the percentage of germinated seeds (SotomayorLeón  Caballero, 1990;Lambardi et al, 1994). Even better results are attained by the in vitro culture of isolated embryos (Troncoso et al, 1991;Sarmiento et al, 1994;Voyiatzis  Pritsa, 1994;Acebedo et al, 1997), particularly at low temperature (Voyiatzis, 1995), showing its potential for use in olive breeding works (Troncoso,1994).…”