Effect of silicon application on four indigenous Zea mays L. varieties for agro-ecological carbon sequestration potential in Nigeria

Phytoliths have the ability to sequester carbon during their formation in plants as a result of absorption of soluble silicon in the form of monosilicic acid in their tissues. The effect of silicon application on phytolith production in four locally farmed varieties of Zea mays L. was investigated in the botanical garden, University of Calabar, Nigeria. Four levels of silicon 0 mg, 2500 mg, 5000 mg, and 7500 mg were added to soil in polythene bags in which seeds of four varieties of Z. mays L.; 91 SUWANI, TZL COMP 4, DT STR Y SYN 2 and IWO SYN C2 were planted. Wet oxidation method was used in the extraction of phytoliths from the leaves of the test plants. The concentration of silicon affected the phytolith quantity of the different varieties significantly (P = 0.05). The highest quantity of phytoliths was recorded in plants treated with 7500 mg silicon concentration. A total of 654 phytoliths were counted making up 26 morphotypes. Phytolith morphotypes were identified using the International Code for Phytolith Nomenclature (ICPN) descriptors. Phytolith morphotypes identified include cross, fusiform, rectangle and elongate which also ranked the highest in abundance with 91, 87, 85, and 70 phytoliths respectively in the four varieties while acicular, unciform, stellate and carinate morphotypes were amongst the least in abundance. Unidentified phytoliths comprised 1.53 percent of the total number of phytoliths counted. Four morphotypes; cross, cuneiform, elongate, and rectangle occurred in all four varieties studied. The results obtained from this study indicate that increased availability of silicon enhanced the phytolith production of the four varieties studied, therefore its implication in carbon sequestration. The opinion here is that the number of phytoliths will positively affect the amount of carbon occluded by the plant