A Method for Silicon Analysis in Citrus and Horticulture Leaf Tissue

Abstract

Silicon (Si) is classified as a beneficial element in higher plants. Although there is an abundance of literature on Si extraction and analysis in graminaceous crops such as rice and sugarcane, there is limited information on the validation of these methods for most dicotyledonous horticultural crops. These methods include gravimetric extraction, which requires a larger sample size the smaller the Si content in the test plant. An autoclave inductive digestion is considered effective by some and criticized by others due to the use of a strong oxidant and its sensitivity to the level of Si in the plant material. Microwave digestion occurs in a closed system which avoids contamination is quick and results in a high recovery rate due to its high extraction temperature. The aim of this experiment was to validate Si measurement following microwave digestion using inductively coupled plasma optical emission spectrometry (ICP-OES) and molybdenum blue colorimetry. The recovery of Si additions as SiO2 was 82%-96% by ICP-OES and 85-94% by colorimetry. The recoveries did not differ between measurement methods (P>0.05), but the ICP-OES were more consistent. The limit of detection for Si determination by means of ICP-OES and that for the spectrophotometry method were 71 µg L -1 and 330 µg L -1, respectively.

Exogenous Silicon Application Improves Chilling Injury Tolerance and Photosynthetic Performance of Citrus

“…These citrus cultivars are widely cultivated on a commercial scale in South Africa. These two cultivars were selected for the study to represent two genetically distinct citrus species, namely, orange and soft citrus (mandarins) [35].…”

“…Potassium silicate solution was applied as a drench fortnightly over a three-month period at 0, 100, 500, 1000, and 2000 mg L −1 of Si, with four replications and 3 trees per replicate. The optimal Si application rate was determined to be 1000 mg L −1 [35,36] and was selected for the subsequent experiment (i.e., the field trial).…”