Wr. Graves et Hy. Zhang, RELATIVE WATER-CONTENT AND ROOTING OF SUBIRRIGATED STEM CUTTINGS IN 4ENVIRONMENTS WITHOUT MIST, HortScience, 31(5), 1996, pp. 866-868
Air temperature and photosynthetically active radiation (PAR) effects
on relative water content (RWC), rooting percentage, root count, and r
oot mass of unmisted, subirrigated stem cuttings of two taxa were dete
rmined, Leaf RWC of 'Charm' chrysanthemum [Dendranthema x grandiflorum
(Ramat.) Kitamura] decreased until roots initiated and then increased
, was lower for cuttings at 23 degrees C photoperiod/14 degrees C dark
than for cuttings at 31 degrees C photoperiod/22 degrees C dark, and
was lower at 193 than at 69 mu mol . m(-2). s(-1) PAR. Neither tempera
ture nor PAR affected leaf RWC of 'Dollar Princess' fuchsia (Fuchsia x
hybrida Hort. ex Vilm.), which increased linearly before and after ro
ot initiation. Rooting percentage and root count were higher with phot
operiods at 31 degrees C than at 23 degrees C for chrysanthemum after
7 days and for fuchsia after 10 days. Although all cuttings of both ta
xa had rooted after 14 days, root dry mass was higher with photoperiod
s at 31 degrees C than at 23 degrees C regardless of PAR for fuchsia a
nd at 69 mu mol . m(-2). s(-1) PAR for chrysanthemum Propagators wishi
ng to use subirrigation instead of mist, fog, or enclosure can minimiz
e the decline in leaf RWC before root initiation and increase the numb
er and dry mass of roots of chrysanthemum by using 69 mu mol . m(-2).
s(-1) PAR and a 31 degrees C photoperiod/22 degrees C dark cycle. Root
dry mass of fuchsia also can be increased by the use of high temperat
ure, but differences in rooting were independent of changes in leaf RW
C.