Histochemical study of shoot-root apices inPanicum miliaceum Linn. seedlings

Abstract

The histochemical nature of shoot and root apices inPanicum miliaceum L. seedlings was studied using light microscopic histochemical procedures on tissue-sections. The substances localized are: RNA, proteins, polysaccharides and reducing sugars.

The shoot apex generally shows uniform distribution of starch grains in all the zones, the presence of which is noticed more in the subtending area of the shoot apex. RNA is abundant in the flank zones, comparatively low in the corpus region and very low in the subtending area of the shoot apex. Proteins and reducing sugars are rich in all the zones of the apex. Present observation confirms that the shoot apex ofPanicum is quite active metabolically.

In the root apex, the so-called quiescent centre lacks starch, which is present in the cortex and mature root-cap cells. RNA and proteins are low in the quiescent zone, but high in the root-cap initials, procambial strands and cortex. Reducing sugars are rich in the root apex, but low or negligible in mature root-cap cells and in subtending regions of the root. Based on the present study, the quiescent zone could be identified inPanicum root.