http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Temperature and photoperiod regulation of freezing tolerance in selected Pennisetum species
Buffelgrass, Pennisetum ciliare (L.) Link (syn Cenchrus
ciliaris L.), is a warm season C4 grass with origins in
tropical and subtropical regions. Buffelgrass possesses good
drought tolerance and excellent forage characteristics, which
make it valuable for revegetation of semi-arid regions.
However, poor winter survival limits the persistence of
buffelgrass to the warmest areas of the southern U.S. This
study investigated winter survival in several Pennisetum
species. Tiller bases of a buffelgrass x birdwoodgrass
(Cenchrus setigerus L.) hybrid with poor winter survival at
College Station TX, a moderately winter-hardy buffelgrass
genotype (PI 409704) and a winter-hardy species (Pennisetum
orientale L. C. Rich. cv Cowboy) were harvested in December,
January, March, and April. Across entries the freezing
tolerance was greatest in December and declined throughout
the winter. The initial freezing tolerance of PI 409704 was
similar to Cowboy and significantly greater than the hybrid.
Only Cowboy survived the winter. Seedlings of two winter-
hardy species, (Cowboy and Pennisetum flaccidum Griseb. cv
Carostan); two moderately winter-hardy species, (Pennisetum
mezianum Leeke PI 214061 and buffelgrass PI 409704) and
Common buffelgrass with poor winter-hardiness were grown at
either 20/15 or 10/15 []C with a 9 or 15 hr photoperiod. The
photoperiod had no effect on the freezing tolerance. The
freezing tolerance increased under 10/5 []C compared to 20/15
[]C. Carostan had significantly greater freezing tolerance
than Common and the rankings of the five genotypes matched
the expected field survival. Only Carostan calli exhibited
freezing tolerance with a significantly greater freezing
tolerance observed at 7 []C compared with 17 []C.
Differences in expressed proteins were found between growth
at 20/15 and 10/15 []C in Common buffelgrass, PI 214061, and
Carostan using SDS-PAGE and 2-D gel electrophoresis. PI
214061 had 11 new proteins not present in Common, mostly in
the low to medium molecular weight range. Carostan had 19
new proteins not found in either Common or PI 214061. Some
new proteins in Carostan were low to medium molecular weight
proteins and many were high molecular weight proteins.
Callus of Carostan and Common were grown at 17 []C and 7 []C
and compared by 2-D electrophoresis also. Comparison of
novel cold temperature proteins between Common and Carostan
callus and seedlings indicated Carostan had an induction of 2
polypeptides, 30 kD/5.7 pI and 24 kD/5.3 pI, in callus which
were similar to two polypeptides induced in seedlings.
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 41-47.