The effect of low initial medium pH on in vitro white poplar growth

Abstract

The effect of low initial medium pH on shoot and root development of five white poplar (Populus alba L.) genotypes was tested. The shoot height, fresh mass of shoots per jar, dry mass of shoots per jar, number of roots, as well as the length of the longest root were measured and final pH of the media determined, after 35 days of culture in vitro. Three initial pH values of the medium were tested: 3.0, 4.0 and 5.5 as control. Agar solidification at pH 3.0 was not achieved after sterilization in autoclave, but it was successful after sterilizing in a microwave oven. The obtained results indicate that the tested genotypes are able to significantly influence the changes of media pH during culture. The effect of differences among the examined media was significant for biomass accumulation and final media pH. Generally, significantly higher values of fresh and dry shoot mass, shoot height and the longest root length were recorded on a medium with initial pH 3.0 then on a standard medium with pH 5.5.The implications of the obtained results for the improvement of in vitro propagation of white poplars are discussed.

U istraživanju je testiran efekat niske početne pH vrednosti hranljive podloge na razvoj izbojaka i korena pet genotipova bele domaće topole (Populus alba L.). Nakon 35 dana kultivacije u kulturi in vitro mereni su visina izbojaka, sveža masa izbojaka po teglici, suva masa izbojaka po teglici, broj korenova, dužina najdužeg korena i određena je konačna pH vrednost hranljive podloge. Tri početne vrednosti pH medijuma - 3,0, 4,0 i 5,5- ispitane su kao standardna pH vrednost medijuma (kontrola). Problemi sa očvršćavanjem podloge kod podloga sa niskom početnom pH nakon sterilizacije, prevaziđene su sterilizacijom podloge u mikrotalasnoj pećnici. Dobijeni rezultati ukazuju na to da ispitivani genotipovi imaju mogućnost da utiču na promenu pH podloge tokom uzgoja u kulturi in vitro. Većina ispitivanih genotipova bele topole ostvarila je značajno bolji rast i razvoj izbojka i korenovog sistema, kao i akumulaciju biomase na podlozi sa početnom vrednošću pH. U radu se diskutuje o implikacijama dobijenih rezultata za poboljšanje in vitro razmnožavanja bele topole.