Growth‐Regulating Substances in Roots of Wheat

Abstract

The aim of tlie present investigation was to separate und show the effect of j^rowtb-regulating substances in roots of wheat, and especially to find out if there are root growth-regulating substances with actions differing from that of auxin, particularly of tbe anti-auxin type.Material. Wbeat plants were grown in a nutrient solution at 22° C. The roots were harvested 10 to 12 days after germination and immediately extracted; 60 to 200 g. of roots (fresh weight) were used for each extract.Preparation of extracts: After washing the roots were crushed in a little ether and allowed to stand in ether for 48 hours at 5° C in the dark. About 500 ml. of peroxide-free ether were used per 100 g. of roots. Finally the roots were pressed and washed with several portions of ether in a IJiichner funnel. As it was found impo.ssible to carry out the following chromatograjjhy without a preliminary rough separation, only the acid fraction of the extracts was examined after preparation by repeated shaking with NaHCO;j-sohition (pH c. 8.5), acidifying this solution with HCl till pII 3 to 4, and shakiiig again wilh ether. Tbe etber was completely distilled off under reduced pressure in a nitrogen atmospbere. When further preparation was not immediately undertaken, in order to avoid oxidation as far as possible the residue was stored in tbe dark at 5' C in a nitrogen atmospbere until the following day, when it wa.s laken up in etbcr till a final volume of 1.5 ml.Method of separation. The different compounds contained in tbe extracts were separated by means of paper chroniatography, wbich was carried out at 22^ C on Munktell no. OB paper, with n-hutanol saturated with water and ammonia, as described by Luckwill (1), and with descending solvents.[406]

Studies on a Shoot and Root Cell Elongation Stimnlator in Pinus silvestris

“…The earlier investigations, by Lexander (1953) and by Kefford 11955 a), confirmed the observalion of Uennet-(-lark and Kefford thai accelerator-a has a stinuihiting effect, even if it sometimes is weak, on the growth of shoots as well as of roots. Lt'xander showed furthermore that the growth of the roots is due lo cell elongation.…”

“…The chroiniitogiain strips were sectioned and l>ioassayed imrtly in the wbeat root cell elongation test, and partly in the Avena coleoptite section test, 't'hese two tests are nsed rontincly at this inslitntc and are earlier described (liurstrom 1942, Lexander 1953, Fransson 1958.…”

The r�le of abscisic acid in root growth and gravireaction: A critical review

“…On paper chromatograms it had an Rf value distinct from that of IAA and was named by them "inhibitor-(l" . Later, inhibitor-# was found in roots of several species [7] such as Lens culinaris [129], Lycopersicon esculentum [27], Pisum sativum [30], Triticum aestivum [101] and Vicia faba [99] . By the mid-1960s the possibility was being considered [195] that among the naturally occurring inhibitors found in plant extracts, of which inhibitor-/3 was a prominent example, there were some that could be hormones essential for the regulation of growth and development .…”

Auxins and Growth‐Inhibiting Substances in Maize Kernels

“…From tbe figures in tbeir work the presence of exceedingly sruall auiounts of olher substances can be inferred, but they theuiselvos do not menliou this iu tlieir paper. The X3 found by Stove aud Tbimann, however, bas been earlier discovered by Lexander (1953) in extracts of wbeat roots. In the area for X;, in tbe chromatograms she was sometimes able to Iind an indication of growlh stimulation, sometimes not.…”