Silicon supplied via foliar application and root to attenuate potassium deficiency in common bean plants

Abstract

Potassium (K) deficiency affects physiological performance and decreases vegetative growth in common bean plants. Although silicon (Si) supplied via nutrient solution or foliar application may alleviate nutritional stress, research on the bean crop is incipient. Thus, two experiments were carried out: initially, a test was performed to determine the best source and foliar concentration of silicon. Subsequently, the chosen Si source was supplied in nutrient solution via roots or foliar application to verify whether Si supply forms are efficient in alleviating the effects of K deficiency. For these purposes, a completely randomized 2 × 3 factorial design was used, with two levels of K: deficient (0.2 mmol L−1 of K) and sufficient (6 mmol L−1 of K); and Si: in nutrient solution via roots (2 mmol L−1 of Si) or foliar application (5.4 mmol L−1 of Si) and control (0 mmol L−1 of Si). Our findings revealed that Si supplied via foliar spraying using the source of sodium silicate and stabilized potassium at a concentration of 5.4 mmol L−1 was agronomically viable for the cultivation of bean plant. K deficiency, when not supplied with silicon, compromised plant growth. Moreover, root-and-foliar-applied Si attenuated the effects of K deficiency as it increased chlorophylls and carotenoids content, photosynthetic activity, water use efficiency and vegetative growth. For the first time, the role of Si to mitigate K deficiency in the bean crop was evidenced, with a view to further research on plants that do not accumulate this beneficial element.

Effect of Potassium Deficiency on Physiological Responses and Anatomical Structure of Basil, Ocimum basilicum L.

“…After 30 days of treatment, the cultivation of basil on a potassium-depleted medium led to a reduction in plant growth and to the appearance of chlorosis, which increased with decreasing K + concentration in the medium ( Figure 1 ). Our results are in agreement with those reported by dos Santos Sarah et al [ 24 ], who showed that potassium deficiency resulted in chlorosis in the oldest leaves of bean plants cultivated in a hydroponic system. Other researchers found that K + deficiency was manifested by the presence of brown spots on old leaves [ 25 ].…”

“…Our results showed that the content of chlorophyll and carotenoid pigments dropped progressively with low K + concentrations in the medium, except under conditions of potassium deprivation. These results are comparable to those reported by dos Santos Sarah et al [ 24 ], who showed that potassium deficiency in the growing medium decreased chlorophyll content in bean plants. The apparent coordination of the decrease in carotenoid content with that of chlorophylls suggests that chlorophyll and carotenoid biosynthetic pathways, which both occur in the plastids [ 32 ], are synchronously regulated in O. basilicum leaves.…”

Impact of Silicon on Plant Nutrition and Significance of Silicon Mobilizing Bacteria in Agronomic Practices

“…Under K deficiency conditions plants showed low photosynthetic rate, less nutrient uptake and reduced gas exchange which led to stunted vegetative growth. However, Si application relieve the stress by enhancing water use efficiency, increased dry matter with elevated level of chlorophyll pigments [269]. In Chenopodium quinoa plants Si augmentation mitigates the deficiency of N, P, K, Ca and Mg by protecting photosynthetic machinery and its metabolism.…”

“…Moreover, Si amendment increase the membrane integrity, reduce the electrolyte leakage and stabilizes the plant as compared to plants without any Si application [271]. K deficiency is a common problem in bean plant and foliar application of Si limits the drastic effects of deficiency and enhance plant growth and yield [269]. Finally, it is very important to understand the role of silicic acid in the Si-cycle and availability of nutrient under different environment and cropping system to obtain knowledge better nutrients management.…”

Foliar Application of Silicon in Vitis vinifera: Targeted Metabolomics Analysis as a Tool to Investigate the Chemical Variations in Berries of Four Grapevine Cultivars

“…Si can be applied to soil, and several studies have shown its role on nutrient availability on the rhizosphere and root uptake [ 1 ]. On the other hand, this element can also be used by foliar application, as recently described for bean plants where Si foliar application has been used to attenuate potassium deficiency [ 8 ].…”