Unveiling the aluminum tolerance by Tithonia diversifolia grown in acid
soil: insights from morphological, anatomical, and nutritional analysis
Abstract
The objective of this study was to assess the effect of different soil
acidity levels, determined by base-cation saturation (BCS) levels, on
the anatomical, and morphological analyses of the roots, the nutritional
status of the plants, as well as the root and shoot biomass production.
A 107-days greenhouse experiment was carried out, employing a randomized
block design with a 2x4 factorial arrangement. The factors included two
propagation methods (seeds and stem cuttings) and four BCS levels (19%,
39%, 52%, and 63%). There was no observed interaction between
propagation methods and BCS levels regarding root and shoot biomass
production. This indicates that T. diversifolia’s tolerance to
acidic soils is not affected by the propagation method. However,
stem-propagated plants exhibited significantly greater root (31%
increase) and shoot (26% increase) biomass production compared to
seed-propagated plants. Regardless of the propagation method, T.
diversifolia plants grown in soil with a 19% BCS level showed a
substantial reduction in root (45% decrease) and shoot (31% decrease)
biomass compared to the 63% BCS level treatment. The root anatomy and
morphology of T. diversifolia are affected when cultivated in
acidic soils with a 19% BCS level. Nevertheless, the PAS test detected
some mucilage in T. diversifolia roots, suggesting a potential
defense mechanism for Al 3+. The shoot biomass of
T. diversifolia plants cultivated in soil with a 19% BCS level
exhibited greater nutritional values compared to the 63% BCS level. In
conclusion, propagation methods have a limited impact on the tolerance
of T. diversifolia to acidic soils. Despite the negative effects
on root and shoot biomass production, T. diversifolia effectively
maintains nutrient uptake even under acidic soil conditions with Al
3+ availability of 5 mmol c dm
-3.