Two-week old seedlings of Pinus pinaster Ait. were grown in nutrient solutions at pH values ranging from 3.5 to 6.5. Acidity exerted a different influence on the growth of the main and lateral roots, thus changing the morphology of the whole root system. Roots grown at 3.5 pH had the shortest length, but the highest biomass and were markedly thickened. The total number of 2nd order lateral roots per plant was not significantly influenced by pH, whereas their length and the development of 3rd roots were the highest at 3.5 pH and the lowest at 6.5 pH. Mineral nutrition was affected by the pH of the culture solution. The P and Fe concentrations in roots were higher in the 3.5 and 4.5 pH solutions than in 5.5 and 6.5 pH. In contrast, lower K, Ca, Mg and especially Mn contents were found in the roots grown at 3.5 pH. However, needle dry weight was unaffected by low pH and neither chlorosis nor critical levels of mineral elements were observed. These results suggest that the compensatory growth of lateral roots allows P. pinaster seedlings to mantain an adequate nutritional status in the shoot even at highly acidic conditions.
The influence of pH on root morphology and mineral content of Pinus pinaster Ait. seedlings
ARDUINI, IDUNA
;
1998-01-01
Abstract
Two-week old seedlings of Pinus pinaster Ait. were grown in nutrient solutions at pH values ranging from 3.5 to 6.5. Acidity exerted a different influence on the growth of the main and lateral roots, thus changing the morphology of the whole root system. Roots grown at 3.5 pH had the shortest length, but the highest biomass and were markedly thickened. The total number of 2nd order lateral roots per plant was not significantly influenced by pH, whereas their length and the development of 3rd roots were the highest at 3.5 pH and the lowest at 6.5 pH. Mineral nutrition was affected by the pH of the culture solution. The P and Fe concentrations in roots were higher in the 3.5 and 4.5 pH solutions than in 5.5 and 6.5 pH. In contrast, lower K, Ca, Mg and especially Mn contents were found in the roots grown at 3.5 pH. However, needle dry weight was unaffected by low pH and neither chlorosis nor critical levels of mineral elements were observed. These results suggest that the compensatory growth of lateral roots allows P. pinaster seedlings to mantain an adequate nutritional status in the shoot even at highly acidic conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
