Influence of light quality on the germination characteristics of seeds of selected pioneer, unde.-storey and canopy tree species in Kalinzu forest reserve, Uganda

Abstract

The effect of light qu11lity and .rnwiog <lqith 011 seed germination of sdtctc<I pi oneer, u11dcrstorey, secondary colonizer and
canopy tree s1>ecies in Ka linzu Fore.st Reser n- was studied. Seeds of d iffrn·nt srecies were sown under incident rad iation,
neutral shade, interrupted lc:if slrndc, continuous le:if shade, t.li f feren t coloured ligh ts, d; i r kness, on the soil surrace and
in t he soil at a dep th of:tbout l.S cm. There were intcrspccific v:1ria tions in percentage, nites and periods before initiation
or germination among the different light treatments. Seeds of the selected pioneer speci es (Mu~·anga leo-arrerae Hauman
& Leon) only ge rmin :itet.I under incident light, neutral sha de, interrupted leaf shad e, red ligh t and on the so il s urface.
Ni11ely seven percen t of tlw secdi; germinated under incident light nnd 4% under interrupted leaf shade. Seeds of Albizill
gummifera J.F. Gmel (seco ndary rn lon i7..(~r), O.\ ) ' fll/.WS .1pecio.111s DC (u ntfl.'rstorcy) and Ft111f11mici africa11t1 Benth. (canopy)
germinated under incident r n d i : i t i on. ncutr:il slnule, inte rrupted • ~:if shade, continuous leaf shade and darkness. Seeds o r
the pioneer species germinlltcd only on tlu· so il surface heca use of 1he steep light gradient in the upper soil layers. Seeds
of the sub-canopy species germin:i tcd both hclow (with a higher percentage) and on the soil surface.