Effects of Silicon and Salinity on Fruit Yield and Quality of Tomato Grown Hydroponically

Abstract

The effects of silicon added to the nutrient solution either at a standard electrical conductivity (EC) of 2.2 dS m-1 or at an increased EC of 4.8 dS m-1 on yield, nutritional status and fruit quality were investigated in a tomato crop grown in a closed hydroponic system. Si was added in form of a water-soluble potassium silicate compound at a reference concentration of 2.25 mM. The EC was raised either by NaCl or by extra addition of K, Ca, and Mg salts of nitrates and sulfates at rates resulting in the same K:Ca:Mg and NO 3 :SO 4 ratios and NH 4 , P, and micronutrient concentrations in all treatments. The average EC values in the drainage water were 3.7 and 3.4 dS m-1 in the low EC treatments without and with Si supply, respectively, and 5.8, 5.7 and 5.8 dS m-1 in the salinity treatments involving NaCl addition, NaCl and Si addition, and extra nutrients combined with Si addition, respectively. The increase of the EC up to 4.8 dS m-1 by adding NaCl had no significant influence on the fruit yield of tomato, when Si was added to the saline nutrient solution. In contrast, the fruit yield per plant was significantly restricted at this level of salinity, when no Si was added to the NaCl-enriched nutrient solution, or when Si was included but salinity was induced by extra addition of major nutrients. In both cases, the yield depressions were exclusively due to a lower mean fruit weight. The β-carotene and lycopene contents of fruit were significantly increased by Si and nutrient-induced salinity. Both Si and EC enhanced the fruit firmness and the contents of total solid solutes and vitamin C in the tomato fruit. Moreover, the addition of Si significantly restricted the occurrence of blossom-end rot in tomato fruit when the plants were not exposed to salinity.

Response of Soil Application of Diatomaceous Earth as a Source of Silicon on Leaf Nutrient Status of Guava

“…This is due to silicon helps in more absorption of calcium, magnesium, zinc, manganese, and copper in to the plant tissue. Similar results were noticed by Lalithya et al, (2014) in sapota, Bhavya (2010) in Bangalore Blue grapes, Stamatakis et al, (2003) in tomato and Prado and Natale (2005) in passion fruit, Mary (2005) in rose, Kamenidou and Toddy (2008) in ornamental sunflower, Kamenidou et al, (2009) in zinnia and Kamenidou et al, (2010) in gerbera.…”

Antioxidant Content and Quality of Fruits as Affected by Nigari, an Effluent of Salt Industries, and Fruit Ages of Sweet Pepper (Capsicum annuum L.)

“…Nigari also contained Si that might have effect on improvement of β-carotene content in sweet pepper. Stamatakis et al (2003) observed that Si enhanced β-carotene synthesis in tomato that agreed our results in sweet pepper.…”

“…Furthermore, nigari contains Si that might have a positive effect on fruit yield in sweet pepper. Stamatakis et al (2003) found a positive effect of Si addition to the nutrient solution under saline condition in tomato fruit yield. Alexander & Clough (1998) also observed that marketable yield of pepper increased due to increased supply of Ca 2+ , mainly because of decrease in BER-affected fruits.…”

Effect of Silica on Physical and Biochemical Characters of Guava

“…This progressive increase could be related to increase in total soluble solids. Bhavya (2010) obtained the similar result in Bangalore Blue grapes, Su et al, (2011) in apple and Stamatakis et al, (2003) in tomato. …”

“…Similarly, Su et al, (2011) made observations in apple, Bhavya (2010) in Bangalore blue grapes, and Stamatakis et al, (2003) in tomato.…”