Indole-3-acetic acid in root nodules of Alnus glutinosa (L.) Gaertn

McLaughlin, Margaret Elizabeth Edwards (1979) Indole-3-acetic acid in root nodules of Alnus glutinosa (L.) Gaertn. MSc(R) thesis, University of Glasgow.

Abstract

Two aspects of the occurrence of 1AA in nodulated plants of Alnus glutinosa have been investigated. Endogenous levels of 1AA. in root nodule extracts were compared to those from Myrica gale and Vicia faba. The mobility of exogenously-applied radioactive 1AA (1-14C-1AA and 5-3H-1AA.), mainly to the host plant after application to root nodules, but also within alder seedlings after application to the shoot apex, has also been examined. Levels of endogenous 1AA in root nodules were estimated initially by bioassay and GC-MS(S.1.M.). The purity of the extracts proved insufficient for satisfactory analysis, so further purification techniques were developed involving the use of gel permeation chromatography and preparative and analytical high performance liquid chromatography. Estimates of 1AA levels in root nodule and root extracts Alnus glutinosa and Vicia faba, were made by U.V. absorbance of analytical HPLC eluates after satisfactory purification had been achieved. The mobility of radioactive 1AA was followed after introduction of the label into the apical bud and nodule lobe by micropipette injection. A second method of label application to the root nodules, by absorption via an exposed vascular strand of a root nodule, was also investigated. Differences in distribution of radioactivity, as a result of the two methods of application of 1AA to the nodule, suggested that application by micropipette injection avoided direct penetration of the conducting tissue. Much of the methanol soluble radioactivity recovered in extracts of the plant parts in all experiments, remained in the aqueous fraction after solvent partitioning. However, movement of 1AA.-like radioactivity as determined by monitoring of preparative HPLC eluates of acidic ether extracts of the separated plant parts, was shown from the root nodules of alder seedlings to all parts of the host plant. Movement also from the apical bud to the rest of the plant within a 24 hour absorption period, following analysis of acidic ether extracts of plant parts by TLC, was shown. 1AA-like radioactivity (as determined by preparative HPLC) was found in both bark and wood of the stem after application of label to the nodule either by micropipette injection or by absorption via an exposed vascular strand. Since purification of extracts for endogenous 1AA by preparative HPLC, showed that contaminants were still present, further evidence to confirm the mobility of radioactive 1AA both out of and into the root nodules of Alnus glutinos a seedlings is required.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: C T Wheeler
• Keywords: Plant sciences
• Date of Award: 1979
• Depositing User: Enlighten Team
• Unique ID: glathesis:1979-72263
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 24 May 2019 15:12
• Last Modified: 24 May 2019 15:12
• URI: https://theses.gla.ac.uk/id/eprint/72263