Reprinted from HoRtSciENCE, Vol. 19(1), February 1984A publication of the American Society for Horticultural Science, Alexandria, Virginia

Terminology for the Description of DevelopmentalStages of Horticultural Crops

A.E. Watada1, R.C. Herner2, A.A. Kader3, R.J. Roman!3, and G.L. Staby4

Postharvest Working Group,American Society for Horticultural Science

Terms describing or identifying develop-mental stages of horticultural crops are notused consistently, thus the meaning of eachterm becomes ambiguous. The cause for thisdiscrepancy is speculative; however, the dis-crepancy could be minimized if a set of widelyapplicable definitions were available as guidesin selecting the appropriate terms. Lott (2)recommended definitions for the terms "ma-ture" and "ripening" and their derivatives.However, his definitions of the term "ma-ture" and its derivatives were restricted tofruit while it is still attached to the plant, andthe definitions of the term "ripe" and itsderivatives were restricted to physiologicalchanges and conditions which occur in fruitfollowing harvest, which limit the use of termsonly to specific fruits and exclude any ofthose ripening prior to harvest.

Gortner et al. (1) proposed definitions forthe terms "development," "prematura-tion," "maturation," "ripening," and "se-nescence," which were based mainly onphysical and biochemical changes in a givenfruit. Definitions based on physical and bio-chemical parameters of a given fruit accu-rately describe the physiological state of thatfruit, but they limit the applicability of theterms only to those fruit that are similar tothe specified fruit. "Development" as de-scribed by Gortner et al. (1) is restricted toperiod during which new tissue is formed andbrought to morphological completion. As nowunderstood, developmental processes con-tinue to the death of the plant. These andother terms are used to describe stages ofdevelopment not only of fruit, but also thoseof nonfruit vegetables and floral and nurserycrops; therefore, the definitions should bephrased so that the terms are applicable to awide range of horticultural crops. The defi-nitions should be brief but explicit to avoid

Received for publication 19 Mar. 1983. The costof publishing this paper was defrayed in part bythe payment of page charges. Under postal regu-lations, this paper therefore must be hereby markedadvertisement solely to indicate this fact.'Horticultural Crops Quality Laboratory, HSI, ARS,S&E, U.S. Department of Agriculture, Beltsville.MD 20705

department of Horticulture, Michigan State Uni-versity, East Lansing, MI 48824.

'Department of Pomology, University of Califor-nia, Davis, CA 95616.

4FoodSource, Inc., 1221 Anderson Drive, San Ra-fael, CA 94901.

the synonymous use of different, but closelyrelated terms. Terms such as "maturation"and "maturity" unfortunately have dualusages: they can refer to a physiological stageand to the time of harvest. Since these 2 termsgenerally represent different stages of de-velopment, the definitions must indicate thecontext of application. The following defi-nitions have been derived to fulfill these needs:

Development: The series of processes fromthe initiation of growth to death of a plant orplant part.

Growth: The irreversible increase in phys-ical attributes (characteristics) of a devel-oping plant or plant part.

Maturation: The stage of developmentleading to the attainment of physiological orhorticultural maturity.

Physiological maturity: The stage of de-velopment when a plant or plant part willcontinue ontogeny even if detached.

Horticultural maturity: The stage of de-velopment when a plant or plant part pos-sesses the prerequisites for utilization byconsumers for a particular purpose.

Ripening: The composite of the processesthat occur from the latter stages of growthand development through the early stages ofsenescence and that results in characteristicaesthetic and/or food quality, as evidencedby changes in composition, color, texture,or other sensory attributes.

Climacteric period: The period in the de-velopment of some plant parts that involvesa series of biochemical changes associatedwith the natural respiratory rise and autoca-talytic production of ethylene. The climac-teric period consists of the preclimacteric,preclimacteric minimum, climacteric rise,climacteric peak, and postclimacteric phases(Fig. 1).

Aging: Any increment of time which may(or may not) be accompanied by physiolog-ical change.

Senescence: Those processes that followphysiological maturity or horticultural ma-turity and lead to death of tissue.

The stages of development can overlap, asindicated by broken lines at the ends of thesolid lines in Fig. 2. For example, growth ofmost fruit ceases by the early stages of ma-turation but growth of some fruits, such asapples and pears, continues through matur-ation and into the initial part of ripening. Theterm "growth" is restricted to irreversibleincreases in physical characteristics and ex-cludes the reversible, temporary increases that

results from uptake of water or other sub-stances. "Physiological maturity" and "rip-ening" are phenomena generally observedwith many fruits and some flowers but gen-erally not with other organs such as roots,foliage, stems, and tubers. The well-knownterm "climacteric" is included here to em-phasize that the term applies to the respira-tory rise which occurs naturally and notinduced by external stress. The various phasesof the climacteric period are identified dif-ferently by people, thus they are identifiedappropriately in Fig. 1. "Aging" is includedbecause its connotation in a scientific contextcan differ from that of common usage whereaging is equated with senescence (4). In sci-ence, the term "aging" is used when ma-terials such as t issue sl ices, extracts,organelles, and even some mature but un-harvested fruit (e.g., avocados) may agewithout necessarily undergoing changes as-sociated with physiological senescence.

The term "horticultural maturity" is de-fined on a relative scheme as suggested byRyall and Lipton (3), because the term canrefer to any stage of development. For ex-ample, sprouts or seedlings are horticultur-ally mature in the early stage of development,whereas most vegetative tissues, inflorensc-ences, flowers, fruits, and underground stor-age organs become horticulturally mature inthe midstage, and seeds and nuts in the latestage of development (Fig. 2). The stagesdepicted for a specific type of morphologicaltissue also need to be considered on a relativescheme. For example, among the under-ground storage organs, the potato tuber isharvested after the plants have bloomed,whereas carrots and onions are harvested be-

Climacteric peak

Postclimacteric

Climacteric rise

reclimacteric minimum

TIME

Fig. 1. Phases of the climacteric period.

HORTSCIENCE, VOL. 19(1), FEBRUARY 1984

o

DEVELOPMENTUJQ

GROWTH

MATURATION

PHYSIOLOGICALMATURITY

RIPENING

SENESCENCE

SPROUTS

HORTICULTURAL MATURITY

STEMS 8 LEAVES

asparagus, celery, lettuce, cabbage

INFLORESCENCES

art ichoke, broccol i ,caul i f lower

PARTIALLYDEVELOPED FRUITS

cucumber, green bean,okra,sweet corn

FULLYDEVELOPED FRUITS

apple,pear, citrus,tomato

ROOTS 8 TUBERS SEEDS

carrot , onion, potato dry bean

SEEDLINGS

CUT & POTTEDFOLIAGE

NURSERY STOCK

POTTEDFLOWERING CUTPLANTS FLOWERS SEEDS

Ornamenta l Crops

Fig. 2. Stages of development and senescence based on physiological processes and usage of horti-cultural crops.

fore the plants have bloomed. Fruits havebeen separated into 2 groups: those harvestedwhen partially developed and physiologicallyimmature, and those harvested when fullydeveloped and physiologically mature, or evenripe.

These definitions are based on detailed dis-cussions held at several ASHS PostharvestWorking Group meetings and at the 1982Gordon Research Conference on PostharvestPhysiology. Progress reports have appeared

in newsletters of the Working Group. Thedefinitions should serve as a point of refer-ence to minimize ambiguities and encourageappropriate use of these terms by postharvestbiologists and others in describing the de-velopmental stages of horticultural crops.

Literature Cited

1. Conner, W.A. ,G.G. Dull. andB.H. Krauss.1967. Fruit development, maturation, ripen-ing, and senescence: a biochemical basis for

horticultural terminology. HortScience2(4):141-144.

2. Lott, R.V. 1945. The terminology of fruit ma-turation and ripening. Proc. Amer. Soc. Hort.Sci. 46:166-172.

3. Ryall, A.L. and W.J. Lipton. 1979. Han-dling, transportation, and storage of fruits andvegetables. Vol. 1, Vegetables and melons.2nd ed. AVI Publ. Co., Westport, Conn.

4. Webster's New International Dictionary ot theEnglish Language. 1942. Unabridged 2nd ed.G&C Merriam Company, Springfield, Mass.

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