Responses of rose plants cultivar ‘Sonia’ and Rosa indica major to changes in pH and aeration of the root environment in hydroponic culture
1989; Elsevier BV; Volume: 37; Issue: 4 Linguagem: Inglês
10.1016/0304-4238(89)90145-3
ISSN1879-1018
Autores Tópico(s)Plant nutrient uptake and metabolism
ResumoRoots of a rose cultivar 'Sonia' and a rose rootstock Rosa indica major were both able to reduce the pH of a nutrient solution containing ammonium. Root growth was inhibited when plants were exposed to either pH 8 or pH 4 solutions in comparison with plants grown in solution of pH 6. Plant growth, leaf size and content of chlorophyll were not affected in plants at pH 4, while all these variables were reduced at pH 8 in comparison with plants grown at pH 6. After 4 days in solution of pH 8 the leakage of electrolytes from 'Sonia' roots was significantly higher than that from roots of R. indica while at pH 6 no differences were observed. The inhibition of growth of 'Sonia' by high pH was prevented by grafting on a R. indica rootstock, however leaf chlorosis was not prevented. The primary roots of 'Sonia' plants deteriorated completely after 11 days in the high pH solution. During this period roots of R. indica only showed symptoms of partial necrosis. The adventitious roots formed after the decay of the primary roots were more tolerant to the high pH but a decrease in the chlorophyll content was still noted. The growth of both cultivars was significnatly reduced when grown in stagnant nutrient solutions with an uncontrolled pH, without forced aeration. When pH 6 was constantly maintained, the inhibition of growth caused by insufficient aeration was partially prevented. The acidification capacity and tolerance to high pH conditions are proposed as desirable characteristics in breeding of rose cultivars and rootstocks.
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