The response of hydroponically grown lettuce under Mn stress to differentiated application of silica sol

Abstract

A way to alleviate excessive Mn nutrition of plants is through silicon application. The aim of the present study was to examine the effect of different Si concentrations in a nutrient solution and Si plant spraying treatments (in the form of silica sol) on the yielding and nutritional status of hydroponically grown lettuce under Mn-stress. The experiments were conducted under controlled conditions in a phytotron. The influence of the following Si levels in the nutrient solution (5.5-control; 15.5; 23.25 and 31 mg Si dm-3) and foliar sprays (distilled water; Si solution) were investigated. Silicon supplied through fertigation significantly affected the plant's nutrient status and alleviated the Mn stress, increasing fresh matter production, RWC (Relative Water Content) and the number of leaves per plants, while decreasing the share of dry matter. The Si nutrition did not change the content of Mn in the leaves, but caused a significant increase in N, P, Na, Fe and Si concentrations with a simultaneous decrease of Zn and Cu levels. The content of Ca, Mg and K was relatively stable (except for the treatment with the most intensive Si nutrition). Generally, the concentrations of N, P, K, Ca, Mg, Na and Fe within the tested Si range were higher than in the control, while being lower in the case of Zn and Cu. Overall, the foliar application of Si did not change plant yielding, the number of leaves on plants and most macro-and microelement concentration in leaves, but modified significantly the RWC as well as the Cu and Na content. The dry matter content under Si nutrition was varied. In summary, an effective method to alleviate Mn-stress is to apply silica sol to a nutrient solution used for plant fertigation.

Zinc Oxide and Silicone Nanoparticles to Improve the Resistance Mechanism and Annual Productivity of Salt-Stressed Mango Trees

“…The activity of CAT had also increased with the application of 50 mg/L nZnO + 150 mg/L nSi and 50 mg/L nZnO, but 100 mg/L nZnO showed less CAT activity than the control. These results also indicated that a lower enzyme activity was always achieved with the application of 300 mg/L nSi, either alone or in combination with any level of nZnO; this may be because excess Si might cause a nutrient imbalance [71,85], affecting the enzymatic component of the antioxidant system, or due to the inhibition effect of high Si concentrations [87]. A significant reduction in SOD activity, associated with significant increase in POX and CAT activity from one season to another, may infer a less compromised antioxidant system in the 2018 season [94].…”

“…Previous reports showed the role of silicon in increasing the leaf area of banana [68], grapes [69], and potato [70]. Kleiber [71] reported that Si increased leaf fresh weight, relative water content, and the number of leaves per plant, while reducing the dry matter content of salt-stressed lettuce.…”

Alleviation Effect of Selenium on Manganese Stress of Plants

“…Also Si application in nutrient solution (in the form of orthosilic acid) may reduce Mn content in tomato fruits by about 10% [41]. In the case of lettuce the application of the same form of Si did not influence the content of Mn in leaves [42].…”

Effect of choline-stabilized orthosilic acid application on tomato grown under increasing Mn stress

“…lobato et al (2013) stated that an increased Si nutrition under water deficiency caused positive and significant changes of transpiration rate and the chlorophyll (a, b and total) content. Kleiber et al (2015) observed that higher Si concentrations in a nutrient solution (in the form of silica sol) significantly influenced plant nutrient status and alleviated the Mn stress as well as stimulating fresh matter production, rWC (relative Water Content) and the number of leaves in lettuce. The response to Si nutrition could vary depending on a cultivar (lobato et al 2013).…”

“…The earliest studies focusing on this problem were conducted on lettuce as a model plant, using e.g. silica sol and choline-stabilized orthosilic acid (ch-OSA) as sources of Si (Kleiber 2014a, Kleiber et al 2015. Ch-OSA is known as a bioavailable form of silicon (EUrOPEAN FOOd SAFETy AUTHOrITy 2009) and may also be used in human therapy (Spector et al 2008): combined ch-OSA treatment with Ca/Vit d3 had a potential beneficial effect on bone collagen compared to Ca/Vit d3 alone, which suggests that this treatment is of potential use in osteoporosis.…”