Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Free-Radical Chain Reaction and Polymerization of Alkenes02:35

Free-Radical Chain Reaction and Polymerization of Alkenes

The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control01:23

Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control

The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Cycloaddition Reactions: MO Requirements for Photochemical Activation01:12

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Accelerated endogenous growth in Avena coleoptile segments.

Planta·2014
Same author

The stability of the postulated wall-loosening enzyme in acid-induced growth.

Planta·2013
Same author

Identification and metabolic characterization of the Zea mays mitochondrial homolog of the Escherichia coli groEL protein.

Plant molecular biology·2013
Same author

Coordinatively polymeric and monomeric bismuth(III) complexes with pyridine carboxylic acids.

Dalton transactions (Cambridge, England : 2003)·2010
Same author

Cerium(IV)-lanthanide(III)-pyridine-2,6-dicarboxylic acid system: coordination salts, chains, and rings.

Inorganic chemistry·2009
Same author

Solvent water tapes in two hydrates of mu-oxo-bis[bis(2,2'-bipyridine-kappa2N,N')(sulfato-kappaO)iron(III)].

Acta crystallographica. Section C, Crystal structure communications·2006

Related Experiment Video

Updated: Jun 25, 2026

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
12:27

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

Published on: September 8, 2013

Kinetics of shoot inversion-induced ethylene production in Pharbitis nil.

T K Prasad1, M G Cline

  • 1Department of Botany, Ohio State University, Columbus 43210, USA.

Botanical Gazette (Chicago, Ill.)
|January 1, 1986
PubMed
Summary

Shoot inversion significantly increases ethylene production in Pharbitis nil shoots. This response, involving 1-aminocyclopropane-1-carboxylic acid, can be rapidly controlled by altering shoot orientation.

Keywords:
NASA Discipline Number 40-10NASA Discipline Plant BiologyNASA Program Space BiologyNon-NASA Center

More Related Videos

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
07:28

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

Published on: November 27, 2015

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Related Experiment Videos

Last Updated: Jun 25, 2026

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
12:27

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

Published on: September 8, 2013

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
07:28

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

Published on: November 27, 2015

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Area of Science:

  • Plant Physiology
  • Plant Hormones
  • Ethylene Biosynthesis

Background:

  • Ethylene is a crucial plant hormone regulating various growth and developmental processes.
  • Mechanical stimuli, such as shoot inversion, are known to influence plant hormone production.

Purpose of the Study:

  • To investigate the effect of shoot inversion on ethylene production in Pharbitis nil.
  • To determine the characteristics of the ethylene response to shoot inversion, including its latency, persistence, and re-inducibility.

Main Methods:

  • Measuring ethylene production in Pharbitis nil main shoots subjected to inversion.
  • Analyzing the production of 1-aminocyclopropane-1-carboxylic acid (ACC), the ethylene precursor.
  • Experimenting with excised stem segments and intact stems to assess response dynamics.

Main Results:

  • Shoot inversion induced a significant increase in ethylene production with a latency of approximately 2.75 hours.
  • The ethylene response was found to be non-persistent, allowing for rapid termination and reinitiation by altering shoot orientation.
  • ACC production patterns mirrored ethylene production, and both intact stems and excised segments demonstrated inducible, inhibitable, and reinducible ethylene evolution.

Conclusions:

  • Shoot inversion is a potent stimulus for ethylene production in Pharbitis nil.
  • The plant's ethylene response to mechanical stress is dynamic and rapidly adaptable.
  • Ethylene production induced by shoot inversion is independent of tissue wounding.