Paclobutrazol, PBZ is a plant growth retardant and triazole

Triazole

Triazole refers to either one of a pair of isomeric chemical compounds with molecular formula C2H3N3, having a five-membered ring of two carbon atoms and three nitrogen atoms.The two isomers are:*1,2,3-Triazole 100px*1,2,4-Triazole 100px...

 fungicide. It is a known opponent of the plant hormone

Plant hormone

Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...

 gibberellin

Gibberellin

Gibberellins are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence....

. It acts by inhibiting gibberellin biosynthesis, reducing internodial

Internode

Internode may refer to:* A portion of a plant stem between nodes* Internode , an Internet service provider in Australia* Internodal segment, a portion of a nerve fiber...

 growth to give stouter stems, increasing root growth, causing early fruitset and increasing seedset in plants such as tomato

Tomato

The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...

  and pepper. PBZ has also been shown to reduce frost

Frost

Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...

 sensitivity in plants.
PBZ is used by arborist

Arborist

An arborist, or arboriculturist, is a professional in the practice of arboriculture, which is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants...

s to reduce shoot growth and has been shown to have additional positive effects on trees and shrubs. Among those are improved resistance to drought

Drought

A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...

 stress, darker green leaves, higher resistance against fungi and bacteria, and enhanced development of roots. Cambial

Meristem

A meristem is the tissue in most plants consisting of undifferentiated cells , found in zones of the plant where growth can take place....

 growth as well as shoot growth has been shown to be reduced in some tree species.

Application methods

PBZ is normally applied to the soil to be taken up by the roots and transported via the xylem

Xylem

Xylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...

to the upper parts of the plant. Foliar application is mostly ineffective. Seeds can be soaked with PBZ to reduce seedling growth.
PBZ is the active component of Bonzi TM with 4g/l.