Departamento de Fisiologia Vegetal, Universidade Estadual de Campinas, 13.100 Campinas, Brazil

Effects of #-Ecdysone and Altosid on Flowering, Juvenility and Sex Expression

G. M. FELIPPE

With 1 figure

Received January 18, 1979 . Accepted February 16, 1979

Summary

The effects of both /i-ecdysone and altosid upon flowering, juvenility and sex expression are shown.

The effect of altosid and /i-ecdysone was studied in the long-short day plant Kalanchoe gastonisbonnieri under short days conditions. In this plant GA3 substitutes for the long days. The insect hormones had no effect in Kalanchoe.

Sex expression was seen in Cucurbita pepo. /i-ecdysone did not simulate GA3• Altosid slightly delayed the appearance of female flowers.

On Coffea arabica cv. Mundo Novo the buds of the plageotropic branches first appear in the 10th leaf pair and then in pairs thereafter. Altosid delayed the appearance of the plageo­tropic buds.

Key words: /i-ecdysone, altosid, flowering, juvenility, sex expression.

Introduction

In insects juvenile hormone (JH) acts in conjunction with ecdysone to determine whether the moult will go from larval-larval to larval-adult (GILBERT, 1974). fJ-ecdysone has been extracted from several plants (HIKINO and TAKEMOTO, 1974), and the phytoecdysones are found in very high quantities in plants. 4.8 kg of dried Podocarpus leaves yielded 2 g of ponasterone A, an ecdysone-like substance, whereas a similar amount of dried silkworm pupae yields only about 0.1 mg of fJ-ecdysone (GILBERT, 1974). Ajugalactone, which shows an inhibitory action against ponasterone A, has also been found in plants (Ajuga decumbens) (NAKANISHI, KOREEDA and SCHOOLEY, 1974). The occurrence of ecdysones in plants raises the question whether they have any beneficial or adverse effects upon the plants themselves or on phyto­phagous animals in their natural habitat. However, no definite answer has yet been found.

Substances similar to insect juvenile hormone have also been found in plants. The methyl ester of todomatuic acid (juvabione) was isolated from Abies balsamea, and

z. Pflanzenphysiol. Bd. 94. S. 79-84. 1979.

80 G. M. FELIPPE

this substance shows high juvenile hormone actiVIty in Pyrrhocoris apterus (BOWERS et al., 1966). Precocene 1 and 2, which act as anti-juvenile hormones were isolated from Ageratum houstonianum (BOWERS et al., 1976; RONDEsT, 1976).

Ecdysone promotes some growth in the dwarf pea bioassay (CARLISLE et al., 1963). f)-ecdysone did not promote either lettuce hypocotyl elongation or stem elongation in beans, and thus did not simulate the effect of gibberellic acid (FELIPPE, 1979). However, f)-ecdysone in a preliminary experiment seemed to inhibit female flower formation in Cucurbita pepo (FELIPPE, 1979). Altosid (a synthetic juvenile hormone) had no effect upon flowering (FELIPPE, 1977). However, in a preliminary experi­ment, altosid appeared to inhibit female flower formation in Cucurbita pepo (FELIPPE, 1979).

In this paper the effects of both f)-ecdysone and altosid upon flowering, juvenility and sex expression are shown.

Material and Methods

The plants used were Kalanchoe gastonisbonnieri, Coffea arabica cv. Mundo Novo and Cucurbita pepo cv. 40 days. K. gastonisbonnieri, a long-short day for flowering was kept in short days (8 hours sunlight). Coffea and Cucurbita were grown in a green-house in en­vironmental conditions.

Altosid (isopropyl-ll-methoxy-3,7,11-trimethyl-2,4-dodecadienoate) is one of the known synthetic juvenile hormone for insects (HENRICK, STAAL and SIDDALL, 1973). jJ-ecdysone (ecdysterone Rotho) and altosid both in two concentrations (1000 and 5000 ppm), and GA3,

gibberellic acid (at 500 ppm) were used in Kalanchoe and Cucurbita. 10 ,ul pf the solutions were applied with the aid of a micropipette, once in Cucurbita (cotyledon) and nine times (over a period of 24 days) in one of the most apical leaves of Kalanchoe. Altosid at 1000 ppm was brushed on only one pair of leaves of Coffea; in one treatment the altosid was applied beginning from the first (JH-1) and in the other from the 6th pair (JH-6) up­wards. In each application only the youngest pair fully developed received the JH. JH was applied once a week during 44 weeks for JH-1 and 32 weeks for JH-6 (from December 1977 to October 1978).

Results and Discussion

Altosid had no effect upon flowering of Pharbitis nil, Xanthium strumarium, Stevia rebaudiana and Porophyllum lanceolatum, all of them short-day plants for flowering (FELIPPE, 1977). Here, results for a long-short day plant are shown. Kalanchoe gastonisbonnieri is a long-short day plant in which the long days can be substituted by application of gibberellic acid for flowering (VALlo and ROCHA, 1976). The plants were grown in short days and when well developed they were treated with GA3, JH (altosid) and f)-ecdysone. The results can be seen in table 1. It can be seen that after 35 days from the beginning of the treatment, bolting and small blossoms were induced in the GA3-treated plants, and by day 55 all these plants were in full flower. The controls in short days and those treated with altosid or ecdysone did not flower. So ecdysone did not simulate the GA3 effect. It has been

Z. Pflanzenphysiol. Bd. 94. S. 79-84. 1979.

,8-Ecdysone and altosid: juvenility and flowering 81

Table 1: Flowering of the long-short day plant Kalanchoe gastonisbonnieri. 10,tt1 of GA3 (500 ppm), JH (1000 and 5000 ppm) and ,8-ecdysone (1000 and 5000 ppm) applied in an apical leaf twice a week. Plants kept in short-days.

days from beginning of hormonal treatment

35 55 85

Control rosette rosette rosette

GA3 500 ppm bolting and small full flowering full flowering blossoms

ecdysone 1000 ppm rosette rosette rosette 5000 ppm rosette rosette rosette

JH 1000 ppm rosette rosette rosette 5000 ppm rosette rosette rosette

shown (FELIPPE, 1979) that ecdysone did not simulate the GAs effect in lettuce and beans.

FELIPPE (1979) showed in a preliminary experiment that both altosid and ecdysone delayed the appearance of female flowers in a Cucurbita cv., like gibberellic acid. The experiment was repeated with a higher number of plants of the same cultivar and with more concentrations of JH and p-ecdysone. The results are shown in table 2 and figure 1 A. Table 2 shows the leaf in which axil the first female flower appeared, being leaf 8 for control and leaf 14 for the GA3-treated plant. Thus GAs at 500 ppm strongly delayed the appearance of the first female flower. No effect of ecdysone could be seen (compare the two concentrations used), and a small delay in the case of the JH (two leaves later at the 5000 ppm concentration). In figure 1 A the per­centage of plants in which the female flowers appeared till the 10th leaf (included) and after the 10th leaf is shown, and the difference is very clear between control and GAs-treated plants. No effect of ecdysone can be seen, but it seems that altosid did retard the appearance of the first female flower, although the concentration was 10 times stronger than that of GAs, and the effect smaller. So it seems that in this case JH simulates, in part, the effect of GA3, but ecdysone does not, thus the results of the preliminary experiment for ecdysone can not be accepted (FELIPPE, 1979).

Table 2: Sex expression on Cucurbita pepo cv. 40 days. Leaf in which axil appeared the first female flower.

Concentration GAs JH Ecdysone ppm

o (control) 8 8 8 500 15

1000 9 9 5000 10 8

Z. Pjlanzenphysiol. Bd. 94. S. 79-84. 1979.

82 G. M. FELIPPE

A

LIOO 01

~ 0 ;;:

.. 80 ri E 01 ...

t 60 .. .&. .... . ~~ .... t: 01 III ., L. Q.

III 20 .... t: II Q.

... 0

o'l C Ecd. JH GA3 1000 5000 1000 5000 500 ppm

B C ..: em u

ILSDS% t: II

!,---Z 40 40 .~ r---f ... 0 30 30 .. 01 II "ii. .&. 20 20 .... . §

.. .... t: 10 10 .!! Q.

'0 EZ. ~ 0 C JH-I JH-6

Leaf number

Fig. 1: Effects of p-ecdysone and altosid (JH) in Cucurbita pepo cv. 40 days and Coffea arabica cv. Mundo Novo. A. Changes on sex expression in C. pepo. 10,u1 of GAs (500 ppm), JH (1000 and 5000 ppm) and p-ecdysone (1000 and 5000 ppm) were applied with a micropipette in one cotyledon. Before leaf 10: open; after leaf 10: shaded. - B. Appearance of the pair of plagiotropic buds on the axil of the pair of leaves of Coffea. Control: open circle. JH-l: closed triangles. JH-6: closed squares. - C. Height (em) of Coffea plants. Plants measured from the soil to the stem axis when the plagiotropic branch started to appear. LSDS % is also presented.

Z. Pjlanzenphysiol. Bd. 94. S. 79-84. 1979.

P-Ecdysone and altosid: juvenility and flowering 83

Coffea cv. Mundo Novo presents axillary dormant buds from the cotyledons up­wards in the axil of each leaf pair. If the apex is removed, these buds come out of dormancy and form orthotropic branches, one of which will substitute the main axis. Coffea also produces a second type of bud just above the orthotropic branch buds. These buds always develop into plagiotropic branches, and in the cv. Mundo Novo the plagiotropic buds only appear just above the axil of the 10th leaf pair. Thus the appearance of plagiotropic buds is considered by us as the end of the ju­venile period. The aim of the experiment in which altosid was applied in Coffea cv. Mundo Novo was to see if the JH would maintain the plants in a juvenile state, retarding the appearance of the plagiotropic buds. An early (JH-1) and a late ap­plication (JH-6) were tried. It has been shown that altosid did not alter the mi­nimum leaf number for flowering (FELIPPE, 1977), and according to VINCE-PRUE (1975) the concept for minimum leaf number is close to, but not exactly the same as the concept of juvenility.

The results for Coffea are shown in figure 1 Band 1 C. In figure 1 B can be seen that the plagiotropic buds appeared with the 10th pair, and by pair 12 all the plants presented the buds. On the JH-1 treatment only 15 Ofo of the plants presented the buds on the 10th pair, and the buds were delayed until the 12th and 13th pairs. The JH-6 is intermediate between the control and JH-l. Thus, JH delayed the appearance of the buds and thus maintained the plants longer in a juvenile state, but, the effect is really very small when one remembers the amount of altosid that a plant treated from the first pair received. The exact quantity is unknown as the solution was brushed on the leaf, but JH at 1000 ppm was applied once a week during 44 weeks on both leaves of the pair.

The growth of the plants, when considered as height, was also decreased by altosid treatment (Figure 1 C).

Altosid therefore seems to have a certain effect, delaying female flower forma­tion in Cucurbita and retarding growth of Coffea. Ecdysone was completely inactive in all experiments. According to GEUNS (1978) one should therefore be cautious when interpreting results obtained with crude extracts of unknown hormone composition, like those of CARLISLE et ai., (1963).

Acknowledgements

Many thanks are due to LILIAN ZAIDAN and SEBASTIANA R. Vieira for technical assistance, Dr. GEORGE SHEPHERD for correcting the English and REGINA HELENA L. BERGAMIN for typing the manuscript.

References

BOWERS, W. S., H. M. FALES, M. L. THOMPSON, and E. C. UEBEL: Juvenile hormone: iden­tification of an active compound from balsam fir. Science 154, 1020-1021 (1966).

BOWERS, W. S., T. OHTA, J. S. CLEERE, and P. A. MARSELLA: Discovery of insect anti­juvenile hormones in plants. Science 193, 542-547 (1976).

z. PJlanzenphysiol. Bd. 94. S. 79-84. 1979.

84 G. M. FELIPPE

CARLISLE, D. B., D. J OSBORNE, P. E. ELLIS, and J. E. MOORHOUSE: Reciprocal effects of insect and plant-growth substances. Nature (Lond.) 200, 1230 (1963).

FELIPPE, G. M.: Effect of insect juvenile hormone upon flowering. Z. Pflanzenphysiol. 85, 269-271 (1977).

- Insect growth hormones and their effect on some plants. II Congr. Latinoamericano de Bot. In press (1979).

GEUNS, J M. c.: Steroid hormones and plant growth and development. Phytochemistry 17, 1-14 (1978).

GILBERT, L. r.: Endocrine action during insect growth. In: GREEP, R. O. (Ed.): Recent pro­gress in hormone research 30,347-390. Academie Press, New York, 1974.

HENRICK, C. A., G. B. STAAL, and J B. SIDDALL: Alkyl 3,7,1l-trimethyl-2-,4-dodecadieno­ates, a new class of potent insect growth regulators with juvenile hormone activity. Agric. and Food Chern. 21, 354-359 (1973).

HIKINO, H. and T. TAKEMOTO: Ecdysones of plant origin. In: BURDETTE, W. J (Ed.): In­vertebrate endocrinology and hormonal heterophylly, 185-203. Springer-Verlag, Berlin, 1974.

NAKANISHI, K., M. KOREEDA, and D. A. SCHOOLEY: Recent studies on ecdysones. In: BURDETTE, W. J (Ed.): Invertebrate endocrinology and hormonal heterophylly, 204-217. Springer-Verlag, Berlin, 1974.

RONDEST, J: Les antihormones juveniles: pesticides de demain. La Recherche 7,975 (1976). VALIO, r. F. M. and R. F. ROCHA: Physiological effects of steviol. Z. Pflanzenphysiol. 78,

90-94 (1976). VINCE-PRUE, D.: Photoperiodism in plants. 444 pp. McGraw Hill, London, 1975.

G. M. FELIPPE, Departamento de Fisiologia Vegetal, Universidade Estadual de Campinas, 13.100 Campinas (Barao Geraldo) Brazil.

Z. Pjlanzenphysiol. Bd. 94. S. 79-84. 1979.