A biosystematic investigation was undertaken in 15
species and three subspecies of the genus Aster, in western
North America. Previous studies had been based entirely on
external morphological features, and it was believed that
much could be learned about the natural affinities of the
taxa by exploring their cytological and...
An investigation was undertaken to determine whether
potassium is indeed necessary for the in vivo synthesis of a
specific protein. The effects of univalent cations on the
inductive formation of nitrate reductase and on the level of
activity of representative non-adaptive enzyme are presented.
Cultures of Neurospora crassa were grown...
Twelve sites of uniform topography and soils were selected in
the Pinus ponderosa/Purshia tridentata/Festuca idahoensis Association.
These sites were located in the rain shadow on the east flank
of the Oregon Cascades. A fire history in the form of fire scars on
ponderosa pine was available for nine of these...
The Pacific Coast form of Douglas-fir in natural forest succession
is an intermediate species thriving in the Coast Range and
Cascade Mountains of the Pacific Northwest. This species constitutes
26 percent of the standing timber in the United States, and 24 percent
of the nation's annual timber harvest. Characteristics of...
Crown gall infected and healthy Kalanchoe pinnata (Lam.)
Persoon plants were analyzed for soluble amino acids. Specifically
the amino acids in young leaf, mature leaf, stem, root, and gall
tissues were quantitatively measured. The plants were inoculated
with the bacterium, Agrobacterium tumefaciens (Smith and Townsend)
Conn., on one side of...
Pine needle blight of Pinus ponderosa Laws. caused by
Elytroderma deformans (Weir) Darker is recognized by changes in
the needles, in the bark and in the development of the branches.
Anatomical studies of the host-parasite relation have been made previously
on young pine tissue up to four years of age...
Abundant conidial production occurs from colonized straws and
plants infected with Cercosporella herpotrichoides Fron during the
cool moist months of the growing season. Experiments were
designed to study the survival, inoculum potential and competitive
saprophytic ability of conidia in soil.
Laboratory results indicated that cool moist soil favors the
saprophytic...
A strain of Aphanizomenon flos-aquae Born. et Flah. has been
introduced into culture and maintained since August of 1964 in completely
defined media. It exhibits the planktonic, colonial flake form
found in nature, and both heterocysts and akinetes are present. The
color and size of the flake and general appearance...
Shoot apex senescence is defined as the collective progressive
and deteriorative processes which ultimately terminate the functional
life of the shoot apex. Senescence of shoot apices of Pisum sativum
L. 'Alaska' as measured by cessation of stem elongation was delayed
by removal of flowers and by treatment with gibberellin A₃...
The balsam woolly aphid (Adelges piceae Ratz.) feeds by inserting its stylets intra- and intercellularly into the cortex or outer phloem of the true firs. While feeding, the aphid injects into the bark an unknown stimulatory substance which affects the adjacent cortical parenchyma cells, the activity of the vascular cambium...