The interaction of plant growth regulators with cell membrane constituents

Sheridan, Norman P (1986) The interaction of plant growth regulators with cell membrane constituents. (PhD thesis), Kingston Polytechnic,

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The thesis describes the interaction of auxins with membrane fractions prepared from etiolated epicotyl tissue of ‘Pisum Sativum’ seedling. The interaction of auxins with phospholipids was also examined. Two classes of high affinity binding tissue sites were found in the growing region of the epicotyl tissue. Kinetic analysis of the data resulted in dissociation constant values of: K[sub]1=2.2x 10[sup]-7 M, n[sub]1=1.8x10[sup]-10 moles/g fresh wt; K[sub]2=11x10[sup]-7M, n[sub]2=3x10[sup]-10 moles/g fresh wt. These sites were not found in the non-growing region of the pea epicotyl suggesting that they may be involved in the growth process. From the competition studies reported here, it would appear that site 2 showed greater auxin specificity than site 1 and this could be considered a candidate as an auxin receptor. Sucrose gradient fractionation techniques were employed to further separate the two binding sites and it was shown that site 2 binding was associated with fractions rich in plasma membrane while site 1 was associated with the endoplasmic reticulum. Separation of the solubilized sites by gel permeation methods indicated an apparent molecular weight of 42,000 daltons. IAA was shown to complex with the polar head group region of phospholipids, in CDCl[sub]3, although the strength of the complex was rather low (Kd=1.9x10[sup]-2 Molal). The strength of binding was influenced by the polar head groups of the phospholipids, but did not appear to be affected by the fatty acyl chain length. The physiological significances of such interactions are discussed.

Item Type: Thesis (PhD)
Physical Location: This item is held in stock at Kingston University Library.
Faculty, School or Research Centre: Faculty of Science (until 2011)
Depositing User: Automatic Import Agent
Date Deposited: 09 Sep 2011 21:38
Last Modified: 06 Nov 2018 11:23

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