Adventitious root formation can be inhibited in stem cuttings
of Pisum sativum L. (pea), an easy-to-root species, if the apical
and lateral buds are removed. Application of exogenous auxin to
the apical stump can replace the rooting stimulus produced by the
buds. Root number was reduced by 50 to 100% in the decapitated and
disbudded cuttings supplied with an apical source of auxin if
photosynthesis was inhibited by 50 to 100% by any of several
treatments. The extent to which rooting was reduced was roughly
proportional to the extent to which photosynthesis was reduced.
Basipetal transport of radioactivity from apically applied ¹⁴C-IAA,
as well as basal carbohydrate content, was also consistently
reduced under conditions where photosynthesis was inhibited. It
appears the reduction in rooting due to a reduction in
photosynthesis must take at least two factors into consideration,
the transport of auxin from the apex to the base of the cutting and
the basal carbohydrate content.
The environmental conditions during the stock plant growth are
important to the rooting of cuttings. In the present investigation, when pea and Rhododendron stock plants were subjected to low light or to a period of darkness, the rooting of
cuttings taken from these plants was significantly promoted. For
pea, the promotive effect of darkness was significantly greater
when the entire plant was placed in the dark compared to a
localized darkening of the stem segment from which roots emerge
after excision. The timing of the light and dark periods during
stock plant growth also greatly influenced rooting, the greatest
promotion was observed when the dark period was given immediately
after emergence of the stock plant. This suggests that the root
promoting effect of darkness can be destroyed by a brief period of
light early in the development of the stock plant. The basal
carbohydrate concentration during the first week of rooting was
similar in cuttings taken from stock plants receiving light
throughout the growth period and those receiving a dark period of 4
days, regardless of whether the dark period was given immediately
after emergence or after an exposure to light. This suggests
carbohydrates do not play a major role in the promotion of rooting
due to a dark treatment on the stock plant. / Graduation date: 1985
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26874 |
| Date | 27 April 1984 |
| Creators | Kumpula, Carol L. |
| Contributors | Potter, John R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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