Indian J. of Agricultura Science, v.25, n.4, p.237-252, 1955. SHARMA, S. N.; SIROHI, G. S. The effect of ammonium and nitrate on CO2 assimilation, Germline stem (GS) cells can be isolated from spermatogonia, which shared the characteristics of SSCs and embryonic stem cells (ESCs), and can be passaged