As. Aiello et Wr. Graves, 2 LEGUMINOUS TREE SPECIES DIFFER IN GROWTH AND ION UPTAKE IN HOAGLANDSOLUTION - PHOSPHORUS TOXICITY IN AMUR-MAACKIA, Journal of plant nutrition, 19(7), 1996, pp. 1061-1073
Hydroponic culture of tree seedlings is used commonly to study root bi
ology; however, we have found that two species of woody legumes differ
in their responses to this practice. Seedlings of Amur maackia (Maack
ia amurensis Rupr. & Maxim.) and black locust (Robinia pseudoacacia L.
) were culture in 1, 5, 10, 25, 50, and 100% Hoagland solution #1 for
5 weeks. Total drug mass of black locust increased with increasing sol
ution concentration up to 50%. Amur maackia dry mass was greatest in 5
% solution. Bronzing, chlorosis and necrosis occurred on leaves of Amu
r maackia in solutions 10% and symptom severity increased with solutio
n strength. Leaf phosphorus (P) content of Amur maackia increased from
0.40 to 1.95% of dry mass as solution strength increased from 5 to 50
%. Amur maackia grown in a soil-based medium and irrigated with 50% so
lution showed no foliar toxicity symptoms, and P content of the leaves
of these plants was 0.279%. Laminae of Amur maackia had higher mangan
ese (Mn) content than laminae of black locust at solution concentratio
ns above 5%. Levels of calcium (Ca) and magnesium (Mg) in laminae of A
mur maackia suggest an enhanced ability of this species to absorb ions
from its medium. Results indicate no elemental deficiencies for eithe
r species. We conclude that black locust can be grown hydroponically u
sing standard methods. However, growth of Amur maackia in solution is
inhibited at concentrations of Hoagland solution #1 > 10%, suggesting
a sensitivity to the availability of ions and perhaps an enhanced abil
ity to sequester ions from its medium.