Vol. 76, No. 2: 95-101, 2007 ACTA SOCIETATIS BOTANICORUM POLONIAE 95

STRATIFICATION CONDITIONS DETERMINING SEED DORMANCY RELEASE OF EUROPEAN BLADDER NUT (STAPHYLEA PINNATA L.)

TADEUSZ TYLKOWSKI Laboratory of Seed Biology Institute of Dendrology, Polish Academy of Sciences Parkowa 5, 62-035 Kórnik, Poland e-mail: [email protected] (Received: May 29, 2006. Accepted: September 12, 2006)

ABSTRACT European bladder nut has its northern limit in Poland and is legally protected. Climatic conditions, edible seeds attractive for small animals and seed dormancy to a large extent affect its restocking under natural conditions. The aim of this study was to determine conditions for seed dormancy release. Nuts dried after collection to ca 11% of moisture content (fresh weight basis) may be stored without loss of seed viability for over 1 year in a cold store at the temperature of -3°C. For the purpose of seed dormancy release nuts need to be stratified. Seed dormancy release was found highest after the application of warm-followed-by- cold stratification, first for 4-6 weeks at the temperature of 15°C or at cyclically alternating temperature of 10~20°C (24+24 h/cycle), followed by 16-18 weeks at 3°C. Seeds germinate at 3°C with the same rate as at cycli- cally alternating temperature of 3~15°C (16+8 h/day). Drying of nuts at room temperature to approx. 11% during the warm stratification phase (after 2 or 4 weeks) and further stratification resulted in a significant increase in seed germinability. In some seed lots scarification of nuts (dried during the warm stratification phase) contributes to a further significant increase of seed germinability.

KEY WORDS: scarification; germination, sowing pretreatment.

INTRODUCTION capsule (with 2-3 cases), with 1-4 (7) relatively large, ap- prox. 1 cm in diameter, hard, spherical nuts with a light European bladder nut (Staphylea pinnata L.) is a shrub brown and shiny coat. In English, bladder nut is named due of medium height, up to 5-6 (9) m high, yielding numerous to the appearance of the inflated capsule resembling the root suckers. In Poland this species is found rather rarely bladder. Seeds contained in the capsule may also resemble and is covered by strict legal protection. Bladder nut is hard pistachio seeds, thus in French bladder nut is called a thermophyte and most frequently occupies stands of sou- „false pistachio” (faux pistachier). Fragrant bladder nut thern exposure at the slope foot. Its geographical limit in flowers are white or pinkish, collected in abundant clu- Poland reaches its northern limit, south of 52° parallel. sters, blooming in May or June. They may be autogamous Under natural conditions it is found primarily in forests or entomophilous. and coppices, on limestone sites which do not dry during Oil pressed from nuts was used for lighting in former ti- the vegetation season, located in Silesia, on the Wieluñ- mes. Moreover, bells, rattles and rosaries were made from Czêstochowa Upland and more frequently in the Carpa- seeds with an attractive shiny coat. In the past bladder nut thian Foothills (Gostyñska 1961). Archeobotanical studies was cultivated in relation with magic properties ascribed to in Poland indicate a much broader range of bladder nut in it and used in religious rites and culture rituals (Cieciñski the Tertiary period (Œrodoñ 1992). Staphylea pinnata avo- 2004). To satisfy aesthetic and cultural needs plants were ids lowlands. It occurs in upland areas in river valleys of most frequently dug out and transferred from forests to be central and southern Europe, from southern France (The planted in the vicinity of houses and temples. For this rea- Vosges and Lorraine), to the Balkans in Bulgaria and Kra- son some archeologists are of the opinion that in places snodar on the Black Sea. where bladder nut is growing, remnants of former settle- The first element of the Polish common name [k³okocz- ments may be expected to be found (Lata³owa 1994). ka po³udniowa] refers to the characteristic rattle heard in The considerable weight of bladder nut seeds (Beranová autumn when the wind shakes twigs burdened with ripe and Benediková 2005) prevents its spread over farther di- fruits. The fruit of bladder nut is a leathery, inflated round stances. After falling to the ground they are willingly eaten 96 DORMANCY RELEASE OF STAPHYLEA PINNATA L. SEEDS Tylkowski T. by small animals. Only scarcely seeds grow into seedlings MATERIAL AND METHODS in the vicinity of maternal plants. Seeds may be dissemina- ted by squirrels (Browicz 1959). The introduction of blad- Several experiments were conducted in 2000-2004 at the der nut to large scale cultivation is prevented by the lack of Laboratory of Seed Biology of the Institute of Dendrology insight into methods of seed dormancy release, both in Po- PAS in Kórnik on seed dormancy release and germination land and other countries where this plant is found. in bladder nut. Four of these experiments are presented in The rare occurrence and scarce generative progeny of this study. Seeds for tests were collected at the permission bladder nut within its geographical limits were the reasons of the Minister of the Environment (permit no. BOA-A- why studies were undertaken to develop procedures of seed 135-2330/01/RP) at the beginning of October 2000 and handling to produce seedlings. In order to actively protect 2001 from several shrubs in the Dukla forest district and in an endangered species it is necessary to know first the con- 2001 in the Arboretum in Bolestraszyce. ditions of its propagation. It does not refer here to vegetati- Moisture content (MC) of nuts as a percentage of water ve propagation, connected with cloning and reduction of (fresh weight basis) was determined after their crushing gene pool. Ex situ protection in arboreta and botanical gar- and drying at the temperature of 105°C for 24 h. dens is only a partial solution to this problem. In available Results of laboratory seed germination were transformed literature there is very limited information on generative to arc sin Ö% and subjected to the MANOVA variance propagation of bladder nut. analysis using the Statistica (1997) programme and tested These scarce and frequently divergent pieces of informa- with the use of the Tukey test at the confidence level of tion contributed to our decision to undertake studies on the P=0.05. determination of optimum conditions of seed storage, do- rmancy release and germination of bladder nut.

Germinability (%)

A AB 15~25°C 3~20°C 11.3 fgh 11.3 fgh 8weeks 3°C o.g.

B BB 15~25°C 3~20°C 16.7 efgh 20.0 def 12 weeks 3°C o.g.

C CB 15~25°C 15~25°C 3~20°C 10.7 h 30.0 abc 4weeks 3°C 4weeks 3°C 2weeks o.g.

D DB 15~25°C 15~25°C 15~25°C 3~20°C 20.7 cdef 34.0 ab 4weeks 3°C 4weeks 3°C 4weeks 3°C 2weeks 2weeks o.g.

E EB 20~25°C 3~20°C 15.3 fgh 28.0 abcd 8weeks 3°C o.g.

F FB 20~25°C 3~20°C 24.7 bcde 34.7 ab 12 weeks 3°C o.g.

G GB 20~25°C 20~25°C 3~20°C 17.3 efgh 36.0 a 4weeks 3°C 4weeks 3°C 2weeks o.g.

H HB 20~25°C 20~25°C 20~25°C 3~20°C 19.3 defg 32.0 ab 4weeks 3°C 4weeks 3°C 4weeks 3°C 2weeks 2weeks o.g. Means 17.0 L 28.2 K

Fig. 1. Seed germinability corresponding to stratification thermal layout of Experiment 1. Symbols: A-H – seeds not dried after collection; AB-HB – seeds dried after collection; o.g. – onset of seed germination. Results were tested using Tukey’s T-test. Identical letters denote values which do not differ signifi- cantly at P=0.05. Vol. 76, No. 2: 95-101, 2007 ACTA SOCIETATIS BOTANICORUM POLONIAE 97

Experiment 1 Experiment 2 Non-dried nuts after being collected in 2000 (Dukla Forest Nuts from several shrubs were collected in October 2001 District), with the MC of 32.2% and nuts dried at room tem- in the Dukla Forest District. Empty nuts were isolated after perature to 11.3% were stratified in a substrate. As a substra- separation in alcohol and removed. Full nuts with MC of te a 1:1 (v/v) moist mixture of glass-sand with sieved peat 14.3% were stored in tightly closed containers from 17 with pH of 6.5 was used. Optimum substrate moisture con- October 2001 to 3 December 2002 at the temperature of tent was tested manually by squeezing in the hand – a single -3°C. After storage nuts (in 3 replications 50 nuts each) drop of water should leak between fingers (Gordon and Ro- were used in the experiment (Fig. 2), the aim of which was we 1982, Suszka at all 1996). Nuts, in 3 replications of 50 to compare the effect on seed germination of the drying nuts each, were mixed with the substrate (1:3 v/v) and strati- procedure (for 3 days at room temperature) and drying and fied in a warm-followed-by-cold or warm-cold-warm-cold mechanical scarification after the completion of the warm systems, according to the design presented in Figure 1. phase of warm-followed-by-cold stratification at 15~25o/3°C During the warm phase of stratification cyclically alter- in the substrate. The applied stratification substrate was nating temperature was applied (under controlled condi- identical as in the previous experiment. The warm phase of tions): 15~25°C or 20~25°C in two-day cycles, i.e. 24 h at stratification in the cycle (24+24 h/cycle) lasted for 2, 4 lower temperature and next 24 h at higher temperature per and 6 weeks. The effect of the germination test temperature cycle. In the warm-followed-by-cold phase the warm phase at constant temperature of 3°C and cyclically variable tem- lasted 8 or 12 weeks, while in the warm-cold-warm-cold perature of 3~15°C (in the cycle of 16+8 h/day) on seed system 4-week warm phases were interrupted by a 2-week germinability was also compared. cold phase at 3°C. In both thermal systems after the last Mechanical scarification of dried nuts was performed warm phase there was a long-term (20-24 weeks) cold pha- manually. Nuts with the stigma directed upwards held in se at 3°C, i.e. until the onset of seed germination. two fingers (thumb and index finger) were placed between Once a week during the warm phase and every two we- vice jaws and were carefully crashed over the largest cir- eks in the cold phase stratified nuts/seeds were removed cumference until a characteristic cracking sound of the bre- from 250 ml containers, aired and possible moisture losses aking coat was heard. were eliminated in the substrate, after which they were again placed in containers. To prevent excessive evapora- Experiment 3 tion containers were covered with perforated lids. After collection in the Dukla Forest District in 2000 nuts After the completion of the cold stratification phase, de- dried to MC of 11.3% were stored for 14 months in a tigh- fined by the appearance of the first germinating seeds, se- tly closed container at the temperature of -3°C. After stora- eds were subjected to a germination test at cyclically varia- ge moisture content of nuts decreased to 10.7%. Nuts were ble temperature at 3~20°C (16 h at 3°C and 8 h at 20°C subjected to warm-followed-by-cold stratification in the every day) in identical substrate as during stratification. substrate (as in experiment 1), in 3 replications with 50 se- Seeds were considered germinated when the radicle was eds each (Fig. 3). The warm phase of stratification for 0, 2, over 5 mm long. 4 and 6 weeks was conducted at a constant temperature of

Germinability (%)

A B C 15~25°C 3~15°C 18.0 d-f 16.7 ef 12.0 f 3°C 3°C 22.0 b-f 22.7 b-f 20.7 c-f A – 6 weeks B – 4 weeks 17 weeks C–2weeks

drying for 3 days t D E F 15~25°C 3~15°C 38.7 a-e 32.0 a-f 25.3 b-f 3°C 3°C 33.3 a-f 30.0 a-f 33.3 a-f D–6weeks E – 4 weeks 17 weeks F–2weeks

drying for 3 days + scarification t G H I 15~25°C 3~15°C 41.3 a-d 46.7 ab 54.0 a 3°C 3°C 42.7 a-c 44.7 a-c 45.3 a-c G–6weeks H–4weeks 17 weeks I –2weeks

Fig. 2. Seed germinability corresponding to scheme of warm-followed-by-cold stratification of Experiment 2. Symbol t – drying of nuts for 3 days at room temperature. Results were tested using Tukey’s T-test. Identical letters used to denote values which do not differ significantly at P=0.05. 98 DORMANCY RELEASE OF STAPHYLEA PINNATA L. SEEDS Tylkowski T.

15°C t of Dendrology on 17 December 2001. After determination of moisture content (10.7%) they were packed to contai- dd 3°C 6 weeks 15 weeks ners and stored at -3°C until 14 April 2003. After storage 4 weeks the experiment was conducted according to the design pre- 2 weeks sented in Figure 4. 0 weeks Nuts were stratified in the substrate in 4 replications with 40 nuts, each in the thermal system of 15°/3°C, with the 10~20°C t warm phase of 9 weeks. During this phase nuts were dried for 2 days at room temperature, once after 6 weeks (va- dd 3°C 6 weeks riants A and B) or twice (after 4 and 6 weeks – variants 15 weeks 4 weeks C and D) or three times (after 2, 4 and 6 weeks – variants 2 weeks E and F). Additionally after the last drying nuts were scari- Fig. 3. Scheme of warm-followed-by-cold 15°/3°C or 10~20°/3°C stratifi- fied mechanically in a vice (variants B, D and F). cation of Experiment 3. Symbols: dd – drying of nuts for 5 days; t – me- chanical scarification of nuts. RESULTS 15°C or at cyclically alternating temperature of 10~20°C (changed every 24 h). After the warm phase nuts were Experiment 1 dried for 5 days at room temperature until MC of approx. The weight of 1000 fresh nuts (with MC of 32.2%) was 11%, followed by mechanical scarification as in Experi- approx. 275 g. ment 2. After scarification nuts were stratified in the sub- Irrespective of the applied thermal system during the strate at the temperature of 3°C, until the completion of se- warm phase of stratification, the first germinating seeds ap- ed germination. peared in the cold phase of stratification at 3°C after 20-27 weeks (fresh seeds 4-10%, dried seeds 4-20%). Elevation Experiment 4 of the germination test temperature from 3°C to 3~20°C re- Nuts, collected from several shrubs in 2001 in the Arbo- sulted in a relatively small increase in seed germinability. retum in Bolestraszyce, were sent by mail to the Institute After 4 weeks at 3~20°C germination settled at the level of

A 15°C t Germinability [%] 6 weeks 3 weeks 3°C 3°C 70.3 ab 16 weeks o.g. 9weeks

B 15°C tn 6 weeks 3 weeks 3°C 3°C 73.5 a 5 weeks o.g. 9weeks

C 15°C tt 4 weeks2 weeks 3 weeks 3°C 3°C 70.5 ab 16 weeks o.g. 9weeks

D 15°C ttn 4 weeks2 weeks 3 weeks 3°C 3°C 74.8 a 5 weeks o.g. 9weeks

E 15°C ttt 2 weeks2weeks 2 weeks 3 weeks 3°C 3°C 48.5 b ~16 weeks o.g. 9weeks

F 15°C tttn 2 weeks2weeks 2 weeks 3 weeks 3°C 3°C 55.8 ab ~10 weeks o.g. 9weeks

Fig. 4. Seed germinability corresponding to scheme of stratification layout of Experiment 4. Symbols: t – drying of nuts at room temperature for 2 days; n – mechanical scarification of nuts; o. g – onset of germination. Results were tested using Tukey’s T-test. Identical letters denote values which do not dif- fer significantly at P=0.05. Vol. 76, No. 2: 95-101, 2007 ACTA SOCIETATIS BOTANICORUM POLONIAE 99

10.7-24.7% for fresh seeds and 11.3-36.0% for seeds dried a significantly lower germination level than the other ther- after collection (Fig. 1). mal systems. Initial moisture content of seeds had a strong The highest germination rate was found for seeds dried effect on seed germination – a significantly lower percenta- after collection to the moisture content of 11.3% and next ge of seeds, which were not dried after collection, germina- stratified in the thermal system of 20~25o/3o/20~25o/3°C ted in comparison to dried seeds (Fig. 7). for 4+2+4+23 weeks, respectively. A total of only 17.3% seeds, which were not dried after collection, germinated in Experiment 2 the identical thermal layout system. The highest percentage (54%) of seeds germinated at the After the completion of the germination test most seeds, temperature of 3~15°C, when a 2-week warm stratification which did not germinate and did not show signs of decay, phase was applied, after which seeds were dried and scari- had light-colored coats (in contrast to several decayed se- fied, and after scarification they were stratified at 3°C for eds with dark colored coats). In an experiment, which is 14 weeks (Fig. 8). It also results that as many as 11 other not described in this study, most healthy seeds germinated results (out of 18) did not differ from the highest value at after repeated stratification. P=0.05. It results from the analysis of variance that all the analy- It results from the conducted analysis of variance that ne- zed factors had a statistically significant effect on seed ger- ither the length of the warm phase of stratification nor the minability. The application of cyclically variable tempera- temperature of the germination test were factors significan- ture of 20~25°C during the warm phase of stratification re- tly affecting seed germinability. Such an effect was found sulted in a higher seed germinability than that at the tempe- only for drying and scarification of nuts. After drying and rature of 15~20°C (Fig. 5). Also the thermal layout with an scarification seeds germinated at a significantly higher per- 8-week warm phase (variant A – Figs 1 and 6) resulted in centage than after only drying. In turn, dried seeds germi- nated at a significantly higher percentage than non-dried 30 seeds (Fig. 9). a Experiment 3 20 During stratification at 3°C the first germinating seeds b appeared after approx. 15 weeks. 10 Germination [%] 0 60 15~25°C 20~25°C 3~15°C Temperature ofwarm stratificationphase Fig. 5. The effect of warm phase temperature on seed germinability. Re- 40 sults denoted with identical letters do not differ significantly at P=0.05 (Tukey’s T-test).

30 20 Germination [%] a 20 a a b 10 0 048121620

Germination [%] 0 Weeks ABC D CFI

Thermal layout ofstratification Fig. 8. Course of seed germination at cyclically alternating temperature of Fig. 6. The effect of stratification thermal layout (A, B, C and D – denota- 3~15°C, after stratification at 15~25°C/3°C, with a 2-week warm phase tions as in Figure 1) on seed germination. Results denoted with identical with cyclically variable temperature changed every 24 h, and a cold phase letters do not differ significantly at P=0.05 (Tukey’s T-test). of 17 weeks (C), 16 weeks (F) and 14 weeks (I). In variant F after a warm phase of stratification seeds were dried for 3 days at room temperature, followed by continued stratification at 3°C, while in variant I after drying 30 seeds were additionally mechanically scarified – see Figure 2. a 60 20

b 40 a 10 b

Germination [%] 20 c

0 Germinability [%] 0 ND Control D D+S Seeds Fig. 9. A comparison of seed germination depending on applied procedu- Fig. 7. The effect of initial moisture contents of nuts (N – not dried after re: drying of nuts (D), drying and scarification (D+S) or none of these collection; D – dried after collection) on seed germinability. Results de- (Control), after warm phase of stratification at 15~25°/3°C. The results noted with identical letters do not differ at P=0.05 (Tukey’s T-test). were tested by Tukey’s T-test at P=0.05. 100 DORMANCY RELEASE OF STAPHYLEA PINNATA L. SEEDS Tylkowski T.

100 100 90 3°C Duration 90 3°C Duration of the warm phase of the warm phase 80 80 of stratification of stratification 70 15°/3°C 70 10~20°/3°C 60 60 50 6 weeks 50 6 weeks 40 40 4 weeks 4 weeks

Germination [%] 30 30 Germination [%] 20 2 weeks 20 2 weeks 10 0 weeks 10 0 weeks 0 0 0246810 0246810 Weeks Weeks

Fig. 10. Course of seed germination at 3°C after warm-followed-by-cold stratification at 15/3°C or 10~20°/3°C, with the warm phase of 0, 2, 4 or 6 weeks and a cold phase of 15 weeks. After the warm phase of stratification seeds were dried at room temperature to moisture content of approx. 10%.

Seeds not subjected to warm stratification (control) ger- 80 D D+S minated only at 20% after 18 weeks of stratification at 3°C. a a a a When a 2-week warm phase was applied (irrespective of 60 the temperature: 15°C or 10~20°C) seed germinability at b 3°C increased to over 40%, while after the extension of this b phase to 4 and 6 weeks – to over 50% (Fig. 10). 40 It turned out as a result of the conducted analysis of va-

riance that only the length of the warm stratification phase Germination [%] 20 had a highly significant effect on seed germinability, and not the thermal layout of this phase at a constant temperature of 0 15°C or at a cyclically variable temperature of 10~20°C. 123 After the results were tested using Tukey’s test (Fig. 11) Number ofdrying periods statistically the lowest results were obtained after stratifica- Fig. 12. A comparison of seed germinability after warm-followed-by-cold tion only at 3°C, slightly better after the application of a 2- stratification at 15°/3°C, with a 9-week warm phase during which nuts week warm phase, and the highest after the application of were dried (D) 1, 2 or 3 times or after the last drying seeds were additio- a 4- or 6-week warm phase preceding the cold phase at 3°C. nally scarified (D+S). Results were tested using Tukey’s T-test at P=0.05. Experiment 4 100 Drying performed once or twice during the warm phase 80 3°C of stratification at 15°/3°C, and next their scarification re- sulted in the highest percentage of seed germination (73.5 60 and 74.8%, respectively). However, from the statistical po- 40 int of view these results did not differ significantly from germinability of seeds subjected only to drying and not Germination [%] 20 subjected to mechanical scarification (Fig. 12). It also re- sults from the experiment that drying nuts 3 times had an 0 0 6 12 18 24 30 36 42 48 adverse effect on later seed germination (a significant de- crease in germination to 48.5%, Fig. 12). Weeks In spite of the lack of difference in seed germinability A B between dried nuts and dried and scarified nuts during the Fig. 13. The course of seed germination at 3°C. Cold stratification was preceded by a 9-week warm phase at 15°C. A – nuts dried; B – nuts dried 60 and scarified. Denotations as in Figure 4. 50 a a 40 b warm phase of stratification there was a distinct difference 30 between the course of their germination (Fig. 13). Seeds 20 from dried nuts, whose coat was mechanically scarified, c 10

Germinability [%] during the warm phase of stratification started to germinate 0 as early as after 5 weeks of stratification at 3°C, and the co- 0246urse of their germination lasted as long as to approx. the Weeks ofwarm stratificationphase 20th week. In contrast, seeds from nuts subjected only to Fig. 11. The effect of length of warm phase of warm-followed-by-cold drying during the warm phase of stratification started to stratification on seed germinability. Results denoted with identical letters germinate after 16 weeks of stratification at 3°C, and the do not differ significantly at P=0.05 (Tukey’s T-test). level of their germination settled around the 34th week Vol. 76, No. 2: 95-101, 2007 ACTA SOCIETATIS BOTANICORUM POLONIAE 101

(Fig. 13). Therefore scarification of nuts resulted in shorte- wed a significantly lower germination rate. It can be seen ning the time of seed stratification by ca. 14 weeks. from the above that not every bladder nut seed lot positive- ly responds to applied scarification of nut coats by increa- sed seed germinability. DISCUSSION It needs to be stressed that nut scarification should be conducted solely when they are dried to moisture content Literature data on the conditions of seed dormancy release of 10-14%. Scarification of moist nuts contributes to dama- and germination in bladder nut are exceptionally scarce and ge of the outer layers of cotyledon cells, which in half from contradictory. Bärtels (1982) was of the opinion that in order the side of the embryo axe adhere to the outer coat layers to complete the development of the embryo seeds require and are almost connected. Soon during stratification, the a long-term stratification of as many as 18 months. In turn, damaged cells will be sites where seed decay will initiate. Nikolaeva et al. (1985) stated only (after Misnik 1949) that Seeds with a short radicle (1-3 mm) may be sown to the seeds require long-term cold stratification. Piotto and Di Noi soil in the spring. (2001 and 2003) were of a different opinion, recommending sowing of seeds soon after collection or in the spring after a 24-week stratification (first a 12-week warm stratification ACKNOWLEDGEMENTS followed by a 12-week cold stratification), with no details on the range of thermal conditions. Under natural conditions I wish to express my sincere thanks to the district forest bladder nut propagated from seeds is found in sites of higher manager of the Dukla Forest District, Z. W³adyka, M.Sc, accumulation of humus (Cieciñski 2004). Eng., and Prof. J. Piórecki, Director of the Arboretum in Our experiments on seed germination showed that fully Bolestraszyce for their kind help in obtaining seeds of Eu- ripe nuts, not dried after collection (with MC of over 30%), ropean bladder nut for the purpose of this study. require for dormancy release a long-term warm-followed-by- cold stratification with at least a 12-week warm phase and a cold phase of over 20 weeks at 3°C. A shorter, i.e. 8-week LITERATURE CITED warm phase of stratification resulted in a significant decrease in seed germinability. Cyclically alternating (20~25°C) tem- ANONYMOUS 2001. The official Gazette „Dziennik Ustaw No. 106, item 1176 of 29 September 2001 (in Polish). perature of the warm phase in the cycle of 24+24 h/day resul- BÄRTELS A. 1982. Rozmna¿anie drzew i krzewów ozdobnych ted in a significant increase in seed germinability in compari- [Propagation of ornamental trees and shrubs]. PWRiL, War- son to the temperature of 15~25°C (Fig. 5). However, a signi- szawa. pp. 436 (in Polish). ficant effect on seed germination rate was found to the hi- BERANOVÁ L., BENEDIKOVÁ M. 2005. Morfologická varia- ghest degree for drying of nuts after collection to MC of bilita plodù a semen døinu obecného (Cornus mas L.) a klo- 11.3% before stratification (Fig. 7). koèe zpeøeného (Staphylea pinnata L.). [Fruits and seeds mor- In case of another seed lot (from 2001) it was shown that phological variability of Cornus mas L. and Staphylea pinnata the duration of the warm phase of stratification at 15~25°C, L.]. Zprávy Lesnického Výzkumu 2: 90-101. (in Czech). from 2 to 6 weeks, had no statistical effect on seed germi- BROWICZ K. 1959. O rozmna¿aniu siê k³okoczki po³udniowej nability (Fig. 2). However, as can be seen for seeds from (Staphylea pinnata L.). [On the propagation of the bladder nut (Staphylea pinnata L.]. Rocznik Dendrolog. XIII: 125-130 (in experiment 3 (Fig. 11) the lack or the application of a too Polish). short, only 2-week, warm stratification preceding stratifica- CIECIÑSKI J. 2004. Krzew naszych przodków [A shrub of our tion at 3°C had a significant effect on the lowering of seed ancestors]. Aura – ochrona œrodowiska 3: 34-35 (in Polish). germinability in comparison to the application of warm GORDON A.G., ROWE D.C. 1982. Seed Manual for ornamental phase of 4-6 weeks. trees and shrubs. Forestry Commission, Bulletin No. 59. After the initiation of seed germination during the cold GOSTYÑSKA M. 1961. Rozmieszczenie i ekologia k³okoczki phase of stratification at 3°C, the application of cyclically po³udniowej (Staphylea pinnata L.) w Polsce [The Distribu- variable temperature at 3~15°C (16+8 h/day) had no effect tion and Ecology of the Bladder nut – (Staphylea pinnata L.) on the level of their germinability when compared with the in Poland]. Arboretum Kórnickie VI: 5-71 (in Polish). cold phase at 3°C (Fig. 2). Seeds germinated equally well LATA£OWA M. 1994. The archeobotanical record of Staphylea rd th at both temperatures. pinnata L. from the 3 /4 century A.D. in northern Poland. Vegetation History and Archeobotany, 3 (2): 121-125. In turn, a significant effect on seed germination was fo- MISNIK G.E. 1949. Proizvodstvennaja charakteristika semjan und for a 3-day drying of nuts at room temperature and derev’ev i kustarnikov gorodskich nasaždenij. Moskva, Lenin- their scarification after the completion of the warm phase. grad. pp. 207. (in Russian) Both these procedures contributed to the highest degree to NIKOLAEVA M.G., RAZUMOVA M.V., GLADKOVA V.N. seed germination. Dried seeds from nuts not subjected to 1985. Spravoènik po prorašèivaniju pokojašèichsja semjan. scarification germinated at a statistically lower rate than Izd. Nauka, Leningrad. (in Russian). those from dried and scarified nuts, but to a higher degree PIOTTO B., DI NOI A. (ed.). 2001. Propagazione per seme di albe- than seeds from non-treated nuts (Fig. 9). ri e arbusti della flora Mediterranea [Seed propagation of Medi- In case of seeds collected at the Arboretum in Bolestra- terranean trees and shrubs]. ANPA, Roma. pp. 212. (in Italian). szyce no significant difference was shown in seed germina- PIOTTO B., DI NOI A. (ed.). 2003. Seed propagation of Mediter- ranean trees and shrubs. APAT 16/2003. pp. 108. bility between nuts dried (once or twice) and nuts dried and SUSZKA B., MULLER C., BONNET-MASIMBERT M. 1996. additionally mechanically scarified. Scarification of nuts Seeds of forest broadleaves from harvest to sowing. INRA, has fastened seed germination considerably. In turn, seeds Paris. pp. 295. from nuts subjected to drying repeated three times during ŒRODOÑ A. 1992. K³opoty z k³okoczk¹ [Troubles with Staphy- a warm phase of warm-followed-by-cold stratification sho- lea pinnata L.]. Wiad. Bot., 36 (1/2): 63-67 (in Polish)