El. Camm et Dp. Lavender, PHOTOSYNTHETIC APPARATUS IN COLD-STORED CONIFER SEEDLINGS IS AFFECTEDBY NURSERY AND STORAGE PHOTOPERIOD, Forest science, 39(3), 1993, pp. 546-560
The photosynthetic apparatus of outdoor grown seedlings of white spruc
e (Picea glauca [Moench] Voss) and lodgepole pine (Pinus contorta Doug
l. var. latifolia Englem.) responded in different ways to similar nurs
ery and storage photoperiod treatments. Seedlings of both species were
(1) exposed to natural or short days (SD: 8-hr photoperiod for 4 or 8
wk) during late summer, (2) returned to natural conditions, and (3) s
ubsequently put in indoor storage at 2-degrees-C in the dark or with a
low intensity photoperiod (less-than-or-equal-to 15 mumol m-2-s-1, 8
hr daylength) for a 6 mo storage period starting October, December, or
January. Poststorage measurements of chlorophyll (chl) a fluorescence
in light-stored white spruce showed, relative to dark controls, incre
ased variable fluorescence and decreased photochemical quenching (qP),
with little increase in nonphotochemical quenching (qN). In contrast,
qP was relatively unaffected in lodgepole pine seedlings, although th
e combination of SD treatment followed weeks later by light in storage
induced an increase in qN. The sequentially applied SD treatment plus
light during storage also led to the accumulation of a foliar 23kD pr
otein in pine seedlings. The above foliar responses to the treatments
were only weakly related to effects of treatments on diameter and heig
ht increase assessed 3 mo after spring planting. The interaction of th
e treatments shows that the pine foliage was able to integrate environ
mental signals received months apart.