auxin

American  

[awk-sin] / ˈɔk sɪn /

noun

Biochemistry.

1. a class of substances that in minute amounts regulate or modify the growth of plants, especially root formation, bud growth, and fruit and leaf drop.

---

auxin British  

/ ˈɔːksɪn /

noun

1. any of various plant hormones, such as indoleacetic acid, that promote growth and control fruit and flower development. Synthetic auxins are widely used in agriculture and horticulture

---

auxin Scientific  

/ ôk′sĭn /

1. Any of various hormones or similar substances that promote and regulate the growth and development of plants. Auxins are produced in the meristem of shoot tips and move down the plant, causing various effects. Auxins cause the cells below the shoot apex to expand or elongate, and this (rather than cell division) is what causes the plant to increase in height. In woody plants, auxins also stimulate cell division in the cambium, which produces vascular tissue. Auxins inhibit the growth of lateral buds so that the plant grows upwards more than outwards. They can be produced artificially in laboratories for such purposes as speeding plant growth and regulating how fast fruit will ripen.

---

Other Word Forms

• auxinic adjective

Etymology

Origin of auxin

First recorded in 1930–35; aux- + -in ²

Example Sentences

Plant hormones like auxin and cytokinin have been connected to the angle of root growth in the past, but the mechanisms of that connection have remained poorly understood.

From Science Daily • Feb. 14, 2024

Removing the stem tip reduces the auxin and allows more branches to develop along the stem.

From Seattle Times • Dec. 27, 2023

The tree produces less of a chemical called auxin, and that drop in auxin contributes to a weakening of tissue at the leaf stem’s base, creating what’s known as an abscission layer.

From Slate • Dec. 5, 2023

In 2007, Bayer began to breed a short corn for the region’s farmers by selecting varieties with a mutation that limits transport of another growth hormone, auxin, in the stalk.

From Science Magazine • Oct. 25, 2023

Formula for preparing auxin: The auxin solution is prepared as recommended by G. H. Poesch in the Ohio Agricultural Experiment Station Bimonthly Bulletin, 191, April, 1938.

From Northern Nut Growers Association Report of the Proceedings at the 44th Annual Meeting Rochester, N.Y. August 31 and September 1, 1953 by Northern Nut Growers Association