1Botany Department, Jomo Kenyatta University, PO Box 62000, Nairobi, Kenya
2Botany Department, Nairobi University, PO Box 30197, Nairobi, Kenya
3Botany Department, Kenyatta University, PO Box 43844, Nairobi, Kenya
4Department of Plant Physiology, Bayreuth University, 95440, Bayreuth, Germany