Seed Dormancy and Pre-Treatments to Enhance Germinatio Selectenn I D Albizia Species
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Journal of Tropical Forest Science 8(3): 369 - 380 (1996) ' 369 SEED DORMANCY AND PRE-TREATMENTS TO ENHANCE GERMINATIO SELECTENN I D ALBIZIA SPECIES C. KannanS . Sudhakara*. K , Augustin. ,A Ashoka. K . P e& n College of Forestry, Kerala Agricultural University, P. O. Vellanikkara, Thrissur, Kerala, India - 680 654 Received November 1994 ______ ______ ____ ____ KANNAN SUDHAKARA, S. ,C AUGUSTINE, ,K. ASHOKAN& , ,A. 1996K . ,P . Seed dormancy and pre-treatments to enhance germination in selected Albizia species. An experimen conductes wa t bese th tfino t dt pre-treatmen dou improvo t t e th e germinatio d vigouan n f Albiziao r odoratissima, Albizia procera, d Albiziaan falcataria seeds. Soakin nickee gth d . odoratissimaseedA f o s r mechanicallo y scarified seeds of A. falcataria in flowing water gave the maximum germination percentage and vigour. Scarification with concentrate n gav e largesmi th e0 2 d tr o H0 21 SO r 4fo germination percentage and vigour in A. procera. Seedcoat extract of these seeds inhibited the germination of seeds of yardlong bean, okra, brinjal and rice. Thin Layer Chromatography showe e presencth d a coumarin-lik f o e e substance F witR ha value of 0.22 in the seedcoat of A. odoratissima. The presence of yet another substance was also indicated. Key words: Seed dormancy germinatio- ninhibito- rcoumari- Albizian- odoratissima, Albizia procera - Albizia falcataria KANNAN, C. S., SUDHAKARA, K., AUGUSTINE, A., & ASHOKAN, P. K. 1996. Kedormanan biji benih dan pra-rawatan untuk meningkatkan percambahan spesies- spesies terpilih Albizia. Satu eksperimen telah dijalankan untuk menentukan pra- rawatan terbaik untuk membaiki percambahan dan kesuburan biji benih Albizia odoratissima, Albizia procera dan Albizia falcataria. Merendam biji benih A. odoratissima yang tercalar atau biji benih A. falcataria yang dilelas secara mekanikal, di dalam air yang mengalir memberikan peratus percambahan dan kesuburan yang maksi- mum. Pelelasan dengan H2SO4 pekat selama 10 atau 20 min memberikan peratus percambaha n kesuburada n n yang paling besa i dalad r procera.. mA Ekstran kda kulit biji benih menghalang percambahan biji benih kacang panjang, bendi, terung dan padi. Lapisan Nipis Kromatografi menunjukkan kehadiran bahan seperti kumarin dengan satu nilai RF 0.22 di dalam kulit biji A. odoratissima. Kehadiran bahan-bahan lain juga turut dikesan. Introduction Growing multipurpose tree species (MPTS) is one of the ways to reverse tropical deforestation. Species like Albizia odoratissima, Albizia procera and Albizia falcataria of the family Fabaceae and sub-family Mimosoideae have received great attention because of their multiple uses and under-exploitation. *Author correspondencefor 0 37 Journal of Tropical Forest Science 0 (1996 38 8(3)- )9 :36 Albizia odaratissima is widely distributed as a constituent of many types of mixed deciduous forests (Troup 1921). The dark brown heart wood of this specis is used for house building, carts, wheel furnitured san . Leave twigd loppee san sar r dfo fodder. Albizia procera is commonly found in alluvial soils along streams and swamps (Troup 1921). The heartwood of this tree is very durable and used for carts, furnitur housd ean e building e wooth ; d also yields fine charcoal. Albizia falcataria is one of the fastest growing among the broad leaved tree species in the world tree excellens e.Th i manufacturinr tfo g cattamara paper fo d rm pulpan . Regeneration from e mosseeth s ti d often used cheapesdan t methof do propagation in these species, but the dormancy induced by the thick seedcoat is a great problem in achieving quick germination (Willan 1985). Natural regenera- tio Albiziaf no unsatisfactors i habitas it n yi t (Rai 1978). Msang Maghembd aan e (1986) observed that delayed and irregular germination in the nursery is a serious constraint in the large scale propagation of Albizia. Various treatments tried to break seed dormanc Albizian yi were, soakin t wate ho col n gi f variou r o rdo s temperature r differensfo t durations (Valencia 1973, Gupt Thapliyaa& l 1974, Kemp 1975, Diangana 1985, Granfulah & El-Hadidy 1987, Khan & Tripathi 1987, Bahuguna et al. 1989), mechanical scarification like nicking and puncturing of seedcoat (Khan & Tripathi 1987), nicking and soaking in flowing water for (Sajeevukumah 4 2 1995). al t e r, filin rubbind an g seedcoaf go t (Babele. al t ye 1986) t wirho ,e scarification (Sandiford 1988), hydrogen peroxide treatment (Carneiro 1975) and acid scarification (Rai 1978, Babeley et al. 1986, Rai et al. 1986, Granfula El-Hadidh& y 1987). Among these treatments watet ,ho r scarificatiod nan acid scarification prove more b o dt e successful. Sajeevukumar (1995 . etal ) reported presence th watea f eo r soluble germinating inhibiting chemica seedcoae th n li f to A. procera and A. falcataria. e presenTh t stud conductes ywa formulato dt e effectiv mord an ee practical pre-treatmen breao t t seee kth d dormanc d improvan y germinatioe eth f no odaratissima,. A procera falcataria. A A d an seeds. Another objectiv confiro t s ewa m presence th f chemicaeo l inhibito seedcoae th n ri thesf o t e species with special referenc . odaratissima.A o et Materials and methods Healthy and middle-aged trees of A. odoratissima, A. procera and A. falcataria were selected for seed collection. Details of weather parameters and location of the mother tree e givear s Tabln i Mature. 1 e pod. odoratissima,A f so procera. A d an falcataria. A were collected directly fro crowe mth meany nb pol f hoosd o ean n ko 26 Januar Januar4 2 199y y d 19921Ma an y 0 1991 , 2 respectively. Pods were dried in the sun, beaten with a stick and the released seeds were cleaned by winnowing. Cleaned seeds were mixed, sealed in polythene bags, made air tight and then stored in a refrigerator at approximately 5 °C. The length and width numbed an d f sounoo rpo f werd seedpo e r determinespe d from samplef so 25 pod foun si r replications weighe .Th see d tdan moisture content o thousanfa d seeds were also determined (ISTA 1985) detaile Th .givee sar Tabln i . e2 Journal of Tropical Forest Science 8(3): 369 - 380 (1996) 371 Tabl . Weathee1 r datlocatiod mothee an a th f no r trees Plac seef eo d Annual temperature Annual Species collection ______(°C)______ rainfall Latitude Longitude Altitude Maximum Minimum (mm) (m a.s.l.) Albizia Peechi Reserve 39.7 19.3 2955 10°32N 76°32 E 100 odoratissima Forest A. procera Peechi Reserve 39.7 19.3 2955 10°32N 76°32 E 100 Forest (March) (JAN) A.falcataria K.A.U. Main 39.9 20.9 3623 10°32N 76°1 0E 22.3 Campus, Vellanikkara seed an d d TablcharacteristicPo . e2 s odoratissima, . oA f . proceraA land A.falcataria . Species Mean pod Mean pod Mean number Weight of Moisture length (cm) width (cm) of seeds/pod 1000 seeds (g) (wet weight basis) A. odoratissima 17.1 3.2 8.0 49.4 5.66 C.V) (% . 10.23 9.84 16.00 A. procera 15.6 2.2 9.0 39.3 8.72 C.V) (% . 10.88 11.30 21.80 falcatariaA. 10.0 2.0 14.0 27.9 4.31 C.V. (%) 7.49 12.90 12.60 Seed treatments followine Th g treatments were applie sampledn i seeds 0 10 seed 5 f ,s2 o s eacn hi four replications. Water soaking e seeTh d sample treatee b o t s dpreviousln i wer t epu y heated water (20) 0ml at different temperature thed san ntreatmente alloweTh . h 4 cooo d2 t r s werelfo : T2 (40 °C), T3 (60 °C), T4 (70 °C), T5 (80 °C) and T6 (100 °C). Seeds soaked in water at ambient temperature for 24 h served as the control (Tl). Physical Methods A small portio f seedcoano removes wa t oppositd d en fro e hilue mth eth m (nicking) usin gnaia l cutte thed ran n soake stiln di l water (T7 r flowino ) g water (T8) at ambient temperature for 24 h. In another treatment (T9) , seeds were soake n i stil dfolloweh l 4 wate2 r complety b dfo r e remova e seedcoatth f o l . 372 Journal of Tropical Forest Science 8(3): 369-380 (1996) Mechanical scarification was done by shaking seeds mixed with four times of its volum containen ti f sana o e n horizontadi a t a r l(Approxn directiomi 0 1 r .nfo 160 shakes per minute). After scarification, seeds were separated from sand soaked an stiln di l water (T10 r flowino ) t ambiena g ) wate1 1 T tr ( temperaturr efo 24 h. Chemical methods The seeds were treated with the following chemicals of varying concentrations for different durations, washed thoroughl runninn yi g wate d thean rn soaked in water at room temperature for 24 h. In the case of concentrated sulphuric acid, 50 ml was taken and for all other chemicals 100 ml was used for treating the seeds. Treatment Chemical Concentration Duration T12 Sulphuric acid Concentrated 5 min T13 Sulphuric acid Concentrated 10 min T14 Sulphuric acid Concentrated n mi 0 2 T15 Sulphuric acid 5% 24 h T16 Sulphuric acid 10% 24 h T17 Sulphuric acid 20% 24 h T18 Sulphuric acid 40% 24 h T19 Hydrogen peroxide 1% 12 h T20 Hydrogen peroxide 2%. 12 h T21 Hydrogen peroxide 1% 24 h T22 Hydrogen peroxide 2% 24 h T23 Acetone 5% 24 h T24 Acetone 10% 24 h T25 Acetone 20% 24 h T26 Acetone 40% 24 h T27 Potassium nitrate 0.5% 24 h T28 Potassium nitrate 1.0% 24 h T29 Potassium nitrate 2.0% 24 h T30 Thiourea 0.5% 24 h T31 Thiourea 1.0% 24 h T32 Thiourea 2.0% 24 h T33 Gibberellic acid (GA3) 5 ppm 24 h T34 Gibberellic acid (GA3) m 10pp 24 h T35 Gibberellic acid (GA3) 20 ppm 24 h 3 37 Journal of Tropical Forest 0 (1996Science38 - (3)9 )8 36 : Treatment tespresenco e st th t f germinatioeo n inhibitors o presenctese T th t f egerminatioo n inhibiting chemical e seedcoatth n i s , seeds of A.