Stems of Allium cepa L. contain starch

Abstract

SUMMARYStems oi Allium cepa L. were prepared for histochemical analysis and stained by periodic acid-Schiff reaction and Lugol's iodine for detecting starch grains (amyloplasts). Starch was found in the root cap of the root initials, around the central cylinder vascular tissues of the stem and in the primary thickening meristem during sprouting hut not during dormancy.

Sprouting of the fructan‐ and starch‐storing geophyte Lachenalia minima: Effects on carbohydrate and water content within the bulbs

“…Histological examinations on Helianthus tuberosus showed that low amounts of starch are detectable in the tuber during tuber development and the beginning of sprouting, but not during dormancy (Ernst 1991). A similar result was obtained for onion bulbs (Ernst and Bufler 1994). Fructan, the principal carbohydrate reserve, is found throughout the onion bulb (Darbyshire and Henry 1978), while the occurrence of starch is restricted to the stems (=basal plate).…”

“…Fructan, the principal carbohydrate reserve, is found throughout the onion bulb (Darbyshire and Henry 1978), while the occurrence of starch is restricted to the stems (=basal plate). Starch can be detected in its primary thickening meristem during sprouting but not during dormancy (Ernst and Bufler 1994). These results allow for speculation that the two carbohydrates – fructan and starch – fulfil different roles during specific phenological phases (e.g.…”

Dormancy and sprouting in onion (Allium cepa L.) bulbs. I. Changes in carbohydrate metabolism

“…In this study, macroscopically visible growth of the dormant structure (sprout leaves), but not mitotic activity (Abdalla and Mann, 1963;Matejko and Dahlhelm, 1991;Pak et al, 1995), absence of starch in the primary thickening meristem (Ernst and Bufler, 1994), or (Miedema, 1994), was the basis for dormancy evaluation. As in young photosynthetic leaves (Heath and Hollies, 1965), the leaf blades of sprout leaves started to elongate long before elongation of the leaf sheath (Figure 1), therefore allowing the collection of sprout leaves of the same size-class at each sampling date during the experimental period (Bufler, 2001).…”

Analysis of Fructans from Higher Plants by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

“…In onion (A. cepa L.) bulbs low-molecular-weight fructans are the principle storage carbohydrate, whereas starch is far less abundant (28,29). In onions the total amount of extractable carbohydrates is FIG.…”