J. Agronomy & Crop Science 164, 16—19 (1990)© 1990 Paul Parey Scientific Publishers, Berlin and FiamburgISSN 0931-2250

Department of Crop Sciencey Faculty of Agriculture, University of Peradeniya,Peradeniya, Sri Lanka

Relationship Between Storage and Germinability of Cardamom{Elatteria cardamomum Maton)

U. R. SANGAKKARA

Authors' address: Dr. U. R. SANGAKKARA, Faculty of Agriculture, University of Peradeniya, Peradeniya, SriLanka.

With 2 tables

Received February 20, 1989; accepted May 8, 1989

Abstract

Cardamom seeds are considered recalcitrant, with relatively low retention of germinability during storage.Thus, a study tested the effects of drying temperatures on moisture loss and reduction in germinability ofcardamom seeds. In addition, the effect of storage material and temperatures on retention of germinabilitywas evaluated. The mature seeds of cardamom contamcd a high percentage of water at har\est, andgerminability at harvest was around 62 %, confirming the recalcitrant nature of the seeds. Seed germmabilitywas completely lost at moisture levels below 50 % (dry wt. basis) and higher temperatures reduced moisturelevels and germinability faster. Drying at 20 °C retained some degree of germinabiliry for 7 days. In terms ofstorage, sealed polythene containers and low temperature (5 °C) was optimal for maintaining some degree ofgerminability of cardamom seeds during storage for approximately 15 days.

Introduction

Most tropical food crops produce seeds withlow moisture contents at maturity, which areeasily stored after dehydration. These aretermed orthodox seeds (ROBKRTS 1973). Theviability of these seeds arc maintained by stor-ing at relatively low moisture contents (IPBGR1976). In contrast, seeds of most tropical pe-rennial species have relatively high moisturecontents. These seeds are unable to withstanddehydration while maintaining viability. Thesearc termed recalcitrant seeds (ROBLRTS 1973),and are stored for variable periods of time atrelatively high moisture content (GRAHAM andPATTERSON 1982). In addition, the extent towhich recalcitrant seeds tolerate dehydrationvaries among species.

Cardamom seeds are produced from a pe-rennial shrub Elatteria cardamom Maton. This

species, which is an important tropical spice(PuRSEGLOVE et al. 1981) is widely used inculinary and pharmaceutical trades. The seedsof this species is considered recalcitrant (KING

and ROBERTS 1979) due to their relatively highmoisture content and poor storability. How-ever, relatively few studies have illustrated thestorability of this species. SINGH (1974) reportsthe relatively short lifespan of seeds of car-damom, while PuRst-GLOVE et al. (19SI) indi-cate the loss of seed viability within a few daysafter harvest.

Due to poor storability of cardamom seeds,propagation is carried out vegetatively. How-ever, this technique has many limitations(PuRSEGLOVE et al. 1981), especially in terms ofproducing new varieties. Thus, a study wascarried out to determine the relationship be-tween drying and storage methods on the re-tention of germinability of cardamom seeds.

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Relationship Between Storage and Germinability of Cardamom 17

Materials and Methods

Mature capsules of cardamom (variety Mysore) har-vested from the Department of Minor Export Crops,Matale, Sri Lanka, were placed between moist paperto avoid dessication, and transported on the sameday to the laboratory of the Faculty of Agriculture,University of Peradeniya. These were stored at 5 °Covernight and experiments initiated the next day.

Seeds were carefully removed from capsules, and asub sample tested gravimetrically for moisture con-tent (dry wt. basis) and germinability. The seeds cobe tested for germinability were pretreated with25 % nitric acid to scarify the hard seed coat andwashed in flowing water as recommended by theDepartment of Minor Export Crops, Sri Lanka(1981). The treated seeds were dusted with a fungi-cide (Serasan 40 %) and placed on moist sand in petridishes, covered with 1 mm of sand and placed at20—25 °C. Germmation was tested on four lots of40 seeds and emerged seedlings were counted after 45days, as cardamom seeds germinate in 30—40 days(PURSEGLOVE et al. 1981). The effect of drying tem-peratures on seed moisture content and gcrminabili-ty was tested by drying samples of fresh seeds dustedwith Serasan 40 % at 20, 30 and 40 "C. Subsamplesof approximately 150 seeds were removed at 2 dayinten'als upto 15 days. Seed moisture contents andgerminability was determined in the above describedmanner in lots containing 40 seeds obtained from thesub samples.

The effect of storage method was determined byplacing freshly har\'ested seeds in different materialsat room temperature (22.5 ± 1.8 °C) or at 5 °C(±0.28 *̂ C). The selected material were aluminiumfoil or polythene (Gauge 250 — unsealed or sealedafter seed placement). Small packets containing ap-proximately 120 seeds were made after treating theseeds with Serasan 40 %. These packets were placedin the selected temperatures. One packet of eachmaterial containing seeds was removed from the twotemperature regimes at 2 day inter\'als. The seedswere scarified and germinated as per methods de-scribed earlier. Germination was recorded at the45th day on three lots of seeds, each containing 30seeds.

Results and Discussion

The moisture content of freshly harvested seedwas 75.25 % (±0.42) on a dry weight basis(42.14 % on a wet wt. basis), and germinabili-ty determined at 45 days was 62.3 %(±1.22 %). This indicates the relatively highseed moisture content of cardamom seeds atmaturity which places it in the recalcitrantgroup, and the low germinability in contrast toother tropical orthodox seeds.

The effect of drying temperature on seedmoisture and germination is presented inTable 1. Drying at a higher temperature re-duces moisture contents rapidly. For example,drying at 40 °C reduces the seed moisture con-tent by 5 % in 24 hours primarily due to thehigh hear and ease of dessication of the smallseeds (1000 seed wt. 0.174 g). The seeds lose44 % of their initial moisture content in 5 daysat this temperature. In contrast, moisture re-duction is considerably slower at 20 °C, andseeds lose only 16 % of the initial moisturecontent in 5 days at this temperature.

Recalcitrant seeds lose their germinabilityrapidly, when seed moisture content falls be-low some high critical level (KING and ROBERTS

1979, AKORODA 1984). This is also illustratedby seeds of cardamom (Table 1). The germina-bility of seeds is completely lost at moisturecontents below 50 % (dry wt. basis). The rateof loss of germinability is different at the threedrying temperatures. Seeds dried at 40 °C losemoisture faster, and also germinability, whencompared to seeds dried at 20 and 30 '̂ C. Thisillustrates that dr)''ing at high temperatures caninjure seed tissues due to rapid loss of water,which reduces seed germinability. Seeds driedat 20 °C retains some degree of germinabilityfor a relatively longer period of time (7 days)when compared to 5 and 1—2 days at 30 and

Table 1. Effect of drying temperature on moisture content (dry wt. basis) and germinability (%) of cardamom

Dryingtemperature

Measurement Day 1 Day 3 Day 5 Day 7 Day 9 Day 11

20 °C

30 "C

40 "C

C V%

% moisturegermination %7o moisturegermination %% moisturegermination %

74.2560.472.1561.370.9642.8

68.1154.164.2222.753.1202.2

63.2742.559.7808.842.89

54.3228.249.08

0

37.78

48,0

45,

.23

.73

40.76

8.77 12.25 9.98 13.27 19.24 4.09

18

Table 2. Relationship

TreatmentStorage method

between

Storage

method

temp. ''C

of storage and g

Day 1 Day 3

;erminab

Day 5

ility of cardamom

Germination %Day 7 Day 9 Day 11 Day

S A N G A K K A R A

13Day 15 S,

Alummium foil

Polythene (open)

Polythene (sealed)

C V %

room5°Croom5°Croom5 'C

temp.

temp.

temp.

3647

31

46

5259

5.86

1211082831

54

14.23

018

0

16

21

51

IS.11

002

0

04

11

47

8.77

—0—00

43

11.02

—0

—

00

37

19.45

———

——

28

9.88

———

——

12

16.56

2.73.89.7

5.31.982.6

40 °C respectively. Thus, under normal condi-tions, cardamom seeds need to be dried at lowtemperatures in order to retain some degree ofgerminability.

The relationship between storage tempera-ture and material in mamtammg seed germina-bility is illustrated in Table 2. Germinability ismaintained for a relatively longer period whenstored at 5 °C in contrast to higher tempera-tures. This can be attributed to the retention ofseed moisture of these recalcitrant seeds at5 °C, which is important in maintaining ger-minability (HANSON 1984). Seeds stored atroom temperature (22 °C) in all types of con-tainers lose germinabitity faster, due to morerapid loss of seed moisture at this temperature.

Seeds in all three containers respond in asimilar manner at both temperatures. This sug-gests the importance of storage temperature onretention of germinability of cardamom seeds,which in turn can be related to moisture loss.

Seeds stored in alummium foil lose theirgerminability taster than those stored inpolythene. The permeability of this material,and its heat absorbing capacity affects theseeds, especially if stored at high temperatures.In contrast, polythene which permits gas diffu-sion but not moisture is more suitable forstoring cardamom seeds, especially if sealed.Thus, cardamom seeds stored in sealedpolythene retains some degree of germinabilityupto 7 days at room temperature. If stored at5 °C, germinability although reduced by45—47%, is maintained for 15 days. Thisenables the procurement ol plants from storedseeds which generally loses viability in 2—3days under normal conditions (SINGH 1974).Seeds stored in open polythene bags lose ger-minability faster, primarily due to the unpro-tected nature of the container. However,

poh'thene containers, either open sealed, offera greater degree of protection in maintaininggerminability of recalcitrant cardamom seeds.

Conclusions

This study confirms the recalcitrant nature ofcardamom seeds due to the high moisture con-tent of mature seeds, and relatively low ger-minability, which is lost rapidly. Seed ger-minability is lost completely lost at relativelyhigh seed moisture content (50 % dry wt.basis) and drying temperature has a significanteffect on maintainancc of seed germinability.Cardamom seeds are also affected by storagetemperature and material. Storage of seeds insealed polythene at low temperatures arc con-sidered the best mode ot storing the seeds ofthis recalcitrant species for propagation pur-poses to maintain some degree of germinabilityfor 10—14 days. If drying is required, fungici-dal treatment and slow removal of seed mois-ture under low temperatures (similar to thatunder shade) is considered suitable to maintaingerminability.

Zusammenfassung

Beziehungen zwischen der Lagerung undder Keimfahigkeit von Cardamom (EhttcrijcarcL^momum Maton)

Cardamomsamen werden als schwer keimfahigbetrachtet; ferner ist eine relativ geringe Erhal-tung der Keimfahigkeit wahrend der LagerhaUtung festzustcllcn. Es wurde daher eine Untcr-suchung durchgefiihrt, die Einfliisse trockncn-der Temperaturen aut den Feuchtigkeitsverlustund den Riickgang der Keimfahigkeit von Car-damomsamen zu untersuchen. Zusatzlich wur-de der EinflufJ des Lagermaterials und der

Relationship Between Storage and Germinability of Cardamom 19

Temperaturen auf die Erhaltung der Keimfa-higkeit erfaEt. Reife Samen von Cardamomwiesen einen hohen Wassergehalt zur Erntcauf; ihre Keimfahigkeit zur Ernte betrug rund62 %; das bestatigt die von Natur aus ungiin-stige Keimfahigkeit der Samen. Die Samen-keimfahigkeit ging bei einem Feuchtigkeitsge-halt unter 50 % (Trockcngewichtsbasis) verlo-ren; hohere Temperaturen reduzierten dieFeuchtigkeitsgehalte und die Keimfahigkeit ra-scher. Trocknen der Samen bei 20 "̂ C erhielt ineinem gewissen Umfang die Keimfahigkeit furdie Dauer von sieben Tagen. Im Hinblick aufdie Lagerung erwiesen sich versiegelte Polya-thylenbehalter und eine niedrige Temperatur(5 °C) als optimal fiir die Erhaltung einer ge-wissen Keimfahigkeit von Cardamomsamenwahrend einer Lagerung fiir annahernd15 Tage.

References

AKORODA, M . O. , 1984: Seed dessication and recal-citrance in Tefairia occidentalis. Seed Science andTechnology 14, 327—332.

Department of Minor Export Crops, Sri Lanka,19S1: Cardamom. Technical Bulletin 6, Dept. ofMinor E.xport Crops, Sri Lanka. 13 pp.

GRAHAM, M., and B. D. PATTERSON, 1982: Re-

sponse of plants to low nonfreezing temperatures:Proteins, metabolism and acclimation. Annual Re-view of Plant Physiology 33, 347—372.

HANSON, J., 1984: The storage of seeds of tropicaltree fruits. In: HOLDEN, H. W., and J. T. WlL-LIAMS (eds.), Crop Genetice Resources. Conserva-tion and evaluation. George Allen & Unwin, Lon-don, U.K., 53—62.

IBPGR, 1976: Report of IBPGR Working group onengineering. Design and cost aspects of longtermseed storage facilities. IBPGR, Rome.

KING, M . W. , and E. H. ROBERTS, 1979: The stor-age of recalcitrant seeds — Achievements and pos-sible approaches. IBPGR, Rome. 91 pp.

PuRSEGLOVE, J. W., E. G. BROWN, G. L. GREEN,

and S. R. J. ROBBINS, 1981: Cardamom. In Spices.Longmans, U.K., 581—643.

ROBERTS, E. H . , 1973: Predicting the storage life ofseeds. Seed Science and Technology 1, 499—514.

SiNGM, H. B., 1974: Cardamom. In: Handbook ofPlant Introduction in Tropical Crops. IBPGR,Rome. No. 93, S5—93.