Boyce, P.C. Germinating Aroid Seeds-Some Observations. Aroideana 30
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p. C. BOYCE, 2007 145 Germinating Aroid Seeds - Some Observations Peter C. Boyce Malesiana Tropicals Suite 4, Level 9, Tun Jugah Tower No. 18 Jalan Abdul Rahman 93000 Kuching, Sarawak, Malaysia [email protected] INTRODUCTION quickly once the seed is cleaned of the berry pulp and so the seed should remain The following notes are based on more in the berry until ready to sow. If seed must than 20 years growing aroids from seed in be removed from the berry then it is vital Europe and a further four years doing the that it remains damp but not wet. Placing same in the everwet equatorial tropics of the seed in a folded, moistened kitchen East Malaysia. These notes reflect personal paper towel (not toilet paper, which breaks experience gained from trial and error - down when wet) inside a plastic bag kept mostly the latter - but with records made all the while on what failed and what, very in a cool room is a good temporary storage occasionally, worked but are in no way medium. intended to be neither comprehensive nor equivocal. Cleaning The cleaning methods will VaIY depend General ing on whether the seed is medium to large, Whether sowing seeds in a pot on the or small. For medium or large seeds windowsill in the temperate parts of the (e.g., Alocasia, Aglaonema, Amorphophal world or in trays in the tropics, the crucial Ius, etc.) that are easy to handle they first starting point is fresh seed. Aroid seed is for need be removed and cleaned of any the greater part recalcitrant (does not surrounding beny. The simplest method is withstand storage) and stored seed (that is to squash the berries gently onto kitchen to say commercially bought) very soon paper towel and then separate the seeds loses viability. from the pulp and any seed membrane. The seed membrane tightly adheres to the seed. Buying seed Its presence is detectable by the seed feeling slippery. Gently working the seed between Seed from commercial seed houses thumb and index finger will remove the generally gives poor to non-existent ger membrane, after which the seed will often mination, especially seed of species with feel very slightly rough. It is vital that this little or no endosperm, which includes cleaning is done wearing latex gloves - the Aglaonema. All seed should be purchased fruit pulp of almost all aroids ranges from inside the still-fleshy berry. Dried seed (in mildly to highly irritant. Gently rinse the seed or out of the berry) will have a low to non in a nylon sieve and dry on kitchen paper existent viability rate due to the problems towel for a minute or two to ease handling. of storing aroid seed. Small seeds, aside from being fiddly to handle, have the additional problem that Storage inside each berry the numerous seeds are Aroid seed stores poorly and dried seed embedded in very viscous gel which is will have a very low viability rate. For best water insoluble and thus difficult to re results seed must be sown as fresh as move. The easiest method is to put the possible. Seed viability falls extremely berries into a plastic beaker full of water, 146 ARO IDEA NA , Vol. 30 Fig. 1. Tray suitable fo r seed sowing in the everwet tropics. macerate them w ith the fingers anel then large seeds require to be just covered w ith leave th e bea k er and its contents in a warm, planting med ia and then well watered. shaded place fo r a few days to ferment (it Therea fter keep dam p and moderately w ill smell pretty bad at the end o f th e time shaded. Small and very small seed are best but th e seed w ill come to no harm) . After surface sown and then settled in by water fermentatio n it w ill be fo und that the gel is ing but not covered. very easil y washed o ff by placing th e entire Almost any orga nica ll y ri ch, mo isture beaker contents into a fine nylon sieve retentive yet well-drained med ium w ill under gently running water and w orking produce good germinatio n results. A suit the seed/ gel/pulp mass w ith th e fingers. able selecti on is: The decomposed gel will dissolve and the larger pieces o f berry, etc. , may be re 1:1 gro und sphagnum: Perlite/ coarse Ver moved b y hand. miculite, o r 1: 1 sieved coconut pea t (coir): washed Planting containers and coa rse (2-3 111m) ri ver sa nd, o r planting media 1: 1 sieved coconut pea t (coir): Perlite/ coarse Vermiculite, o r Pl astic pots o r trays are better then clay 1: 1 prop riety soil-less compost: Perlite/ (terracotta). Tn very wet tro pica l habitats coarse Vermiculite p lastic mes h trays o f the type used to drain kitchen dishes (crock ery) are excellent From experience for tro pica l speci es 1: 1 (Fig. 1) . ground sphagnum: Perlite works best in the Aroid seed requires light to germinate so everwet tropics w hile th e 1: 1 pro priety soil do not bury too deeply , if at all . M edium to less compost: Perlite mix is idea l for P. C. BOYCE. 2007 147 Fig. 3. A locasia chaN w ith mature fruits; note that the lower spathe w hile sti ll fres h has split segments that have recurved to reveal the fruit. be underway loosen the bag but do not remove immediately . Allow the plants Fi g. 2. A/ocasia X Po rtodo ra at onset o f inside to acclimatize to the drop in humid fruit maturity; note the persistent lower ity that the loosened bag provides . After spathe beginning to split lo ngitudinally to two or three days rem ove the bag at night reveal ripe orange-red berri es . to allow a period o f cooler temperatures before th e first full day w itho ut a covering. Temperate genera are best germinated in a frost-free greenho use. temperate regions. If using coconut pear (coir) ensure that the source is free o f sa lt NOTES FOR SPECIFIC GENERA contaminatio n; m ost coconut pea t origi nates fro m coastal areas of the tro pics and if no t properl y matured o ften contains signif AWCASIA (including XENOPI-IYA) ica nt sa lt contaminatio n. Temperate genera listed belO\v (Arul11, Size Arisaru m, Siarum & Dracunculus, El17i Alocasia seed is medium to moderately nium and H elicodiceros) benefit from large (on average black peppercorn size) a small q uantity o f mineral soil (c. 0.25) to and easy to handle. w hichever mbc is used. T he seed of these genera should be covered limeston e grit to Home collection the depth o f the seed , rather than sowing media. In most species the seed is mature o nce the persistent lower spathe splits into Germination recurved strips to revea l the orange-red berries (Figs. 2 & 3) although in the A. Idea l conditions fo r germination of trop longiloba complex the lower spathe \v ith ica l genera are a hea ted greenhouse o r in ers and fa lls befo re fruit maturity (Fig. 4). warm climates a shade house . If germinat ing indoors then choose a brightly lit but Cleaning not sunny w indowsill and put the entire pot inside a po lythene bag secured by an Sq uash o nto k itchen paper to\vel; re elastic band. Once germinatio n is seen to move pulp and seed membrane and rinse . 148 AROIDE A, Vol. 30 Fig. 4. Aloeasia long iloba "", ith the fruit d isplayed and the lower spathe w ithered and fallen. Sowing leads to either funga l o r bacterial ro tting. Thereafter, pot-on w ith m inimal root d is Cover to own depth. turbance. Germination Notes 2- 3 weeks at a minimum of 21 °C (70°F) As Aloeasia grow and enter maturity they and a maximum o f 29°C (84°F). Medium become very intolerant o f root disturbance. shade. It is impo rtant that after initial p ri cking OLit plants are potted o n in such a way as to Post germination minimize root damage. A IIO\N the seedlings to continue growing Species (a nd their hybrids) o riginatina until a second lea f has fully developed from limesto ne habitats benefit fro l11 a sca nt before transplanting. topdressing of sm all (Y2 - 1 cm) limesto ne chips. Species and hybrids concerned are: Transplantation A. x Amazonica , A.long iloba 'Iowii' (syn. A. lowii), A. jJ/.I/.eri, A. jJangeran , A. jJrineijJi At the start o f third lea f emergence eulus, A . regi n ula , A. reginae, A. reuersa & transplant into ind ividual pots taking ca re A. rid leyi. In additio n, although their no t to bury the stem base as this in va ri ably habitat is not recorded the following P. C. BOYCE, 2007 149 species also benefit from a limestone Transplantation dressing: A. c!ypeolata, A. nebula & A. sinuata. At the initial potting from germination it will be seen that there will already we an extensive root system and great care should AGLAONEMA, AGLAODORUM & NEPHTHYrIS be taken to prevent root damage. Once Size potted, grow on until the pot is full of roots and then pot on successively into the final and Aglaonema, Aglaodorum Nephthytis container or ready for planting put, avoid seed is large (hazelnut to date stone size) ing root disturbance at each potting.