442-10 Effect of Silicon on Root Morphological Parameter of Silicon Accumulating and Non-Accumulating Plants Under Aluminum Stress.
Poster Number 1317
See more from this Division: SSSA Division: Soil Fertility & Plant NutritionSee more from this Session: Multiple Nutrients and Micronutrients
Wednesday, November 5, 2014
Long Beach Convention Center, Exhibit Hall ABC
The main symptom caused by aluminum (Al3+) stress in plants is root growth inhibition, influencing negatively the water and nutrients uptake. Although silicon (Si) is not considered to be an essential nutrient for plants, it is known to effectively mitigate various abiotic stresses in plants, such as Al3+ stress common in acids soil. However the mechanism of this interaction between Si and Al3+ is not well understood, especially in Si non-accumulator plants as castor beans. The majority of researches on this role of Si had been done on Si accumulators as rice and sugarcane. Moreover there is not any information about that interaction in plants root, since the main effect of Si in plant is on the shoot. So, because of the damage caused by Al3+ on plants is on the root the aim of this study was to evaluate the influence of Si on the root morphological parameter of a Si accumulating plant (upland rice) and Si-non-accumulating plant (castor bean) under Al3+ stress. There were two experiments, the first experiment was upland rice (Si accumulating plant) and second experiment was castor bean (Si non-accumulating plant). The experiments were conducted in nutrient solutions, and were laid out in randomized blocks, (Factorial design, 2x4) with four replications. In the first experiment (upland rice), the treatments included four combinations of Si and Al3+; 1) 0 Si and 0 Al3+, 2) 1.7 mmol L-1 Si and 0 Al3+, 3) 1.7 mmol L-1 Si and 1.4 mmol L-1 Al3+, 4) 0 Si and 1.4 mmol L-1 Al3+ ; imposed on two upland rice cultivars Maravilha (Al3+ susceptible); ANA 7007 (Al3+ tolerant). In the second experiment (castor bean), the treatments were four combinations of Si and Al3+; 1) 0 Si and 0 Al3+, 2) 1.7 mmol L-1 Si and 0 Al3+, 3) 1.7 mmol L-1 Si and 1.1 mmol L-1 Al3+, 4) 0 Si and 1.1 mmol L-1 Al3+; imposed on two castor bean cultivars CRZ 6 (Al3+ susceptible); CRZ 18 (Al3+ tolerant). The root parameters were length, surface area, volume and diameter of upland rice and castor bean plants. Differences were observed in all upland rice root parameters among treatments. The treatments without Al3+ showed better growth over all other treatments. However, there was no significant difference between Si applied with Al3+ and the Al3+ alone treatments in the parameters. Therefore, Si application did not improve the upland rice root development under Al3+ stress. For castor bean root parameters, the treatments without Al3+ showed better root length, surface area and volume over all other treatments, and there were no difference between Si applied with Al3+ and the Al3+ alone for these treatments. However the treatment Si applied with Al3+ showed lower root diameter over all other treatments. The root diameter increased with Al3+ application, it occurred because the root become stunted according of root meristem injury or death and increase the rigidity of the cell wall and their diameter. But in this case, Si applied with Al3+, the Al3+ toxicity did not increase the root diameter of castor bean plants, maybe the Si contributed a little for that, but it needs more studies. Si did not improve upland rice and castor bean root growth under Al3+ stress.
See more from this Division: SSSA Division: Soil Fertility & Plant NutritionSee more from this Session: Multiple Nutrients and Micronutrients