Crop Ecophys Plant Hormones

What are plant hormones?

Nat. substances produced by the plant that coordinate complex steps to control plant behavioral patterns and functions

Do plant hormones act at low or high concentrations?

Low

Are plant hormones produced in one part of the plant and transported to other parts or do they only elicit response locally?

Both

5 classical plant hormones

Auxins, Ethylene, Abscisic Acid, Cytokinin, Gibberellins

Newer Classes of plant hormones

Salicylic Acid, Strigolactones, Jasmonic Acid, Brassinolide

Difference betwn natural plant hormones and PGRs

PGRs= natural or synthetic substances that influence plant growth and development. All natural plant hormones are PGRs, but not all PGRs are natural plant hormones.

Major factor that allows cereal yields to keep up with world population increases

high-yielding varieties, large amounts of fertilizer and pesticides.

Introduction of what genes were crucial to the green revolution

Dwarfing genes

What hormone pathway are dwarfing genes involved in?

GA Gibberellin plant hormone pathway

How do dwarfing genes work in wheat

The Reduced height (Rht) genes of wheat interfere with the signal transduction pathway of the GA growth hormone

How do dwarfing genes work in rice?

The semi-dwarf1 (sd1) gene from rice impairs the biosynthesis of GA

Dwarf =

Semi Dwarf =

Dwarf = 50% or less the height of the normal plant

Semi Dwarf = Mutant variety with height that lies between 50-100% that of the normal plant

Where did wheat dwarfing genes of the Green Revolution originate

Japan

What is Norin 10

Japanese crosses semi-dwarf variety (Daruma) X American high yielding varieties to produce Norin 10. Norin 10 used in breeding programs in the US to produce a number of high-yielding semi-dwarf cultivars.

Norin 10 cross sent to Norman Bourlaug

Norin 10 X Brevor 14

What do Cytokinis do

Stimulate shoot differentiation

What do Auxins do

Stimulate root initiation

What is ABA (Abscicic acid) involved in 😂

Abiotic Stress, Seed Development, Growth and Development

Analog of which hormone may have practical application for reducing water use in plants, and can be substituted for ABA for prolonged periods of time?

ABA

Brassinosteroids do what?

Regulate a wide range of physiological processes including plant growth and development, and plant immunity

Brassinolide

A plant sterol first isolated from pollen of rape. Brassinolide could promote stem elongation and cell division

Which hormones is a good candidate for a commercial biocontrol product as they interfere with ecdysteroids at their site of action

Brassinosteroids

Jasmonic acid (JA) roles

Plant defense (induce proteinase inhibitors, against herbivorous insects), plant development, adaption to environmental stress, plant defense reactions

Which hormone used in seed treatment to stimulate natural anti-pest defense of plants that germinate from treated seeds

Jasmonic acid (JA)

Which hromone can help amerliiorate toxicity in plants caused by abiotic stresses

JAs

Microbial infection increases —— —— (plant hormone) content at the infection site

Salicylic acid

Programmed cell death by binding to receptor NPR3 and mediating degradation of the cell-death suppressor NPR1 hormone to help restrict spread of pathogen

Salicylic acid