Experiment Station Record, Volume 92, January-June, 1945 Page: 62
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62 EXPERIMENT STATION RECORD [Vol. 92
and a key to these amended genera developed by the author and used successfully
during the past season is appended here.
The term viruliferous, E. CARSNER. (U. S. D. A.). (Phytopathology, 34 (1944),
No. 8, pp. 765-766).-The author recommends that the term "viruliferous" be restricted
to mean the status or condition of an insect vector in which it carries
a virus. Its use to describe plant tissue containing virus or virus-infected plants
Nutrient interrelations in lime-induced chlorosis, R. C. LINDNER and C. P.
HARLEY. (U. S. D. A.). (Plant Physiol., 19 (1944), No. 3, pp. 420-439).Lime-induced
chlorosis of plants is distinguished from other types of iron chlorosis
such as true Fe deficiency, upset Mg/Fe balance, and upset phosphate/Fe balance.
Leaves affected with lime-induced chlorosis proved to be high in K but somewhat
low in Ca and Mg, and it was not definitely established whether these nutrient relations
are associated with the cause or are a result of chlorosis. Data are presented
on the distribution of Ca, K, Mg, P, Fe, and Mn in various fractions of green and
chlorotic pear and apple leaves and of green and variegated spiraea leaves. The
K was mostly water-soluble; Mg and Mn were either water-soluble or readily
dissociated by 0.1 N HC1 (except for the small amount of Mg present in the ether
fraction as part of the chlorophyll molecule); Ca, P, and Fe, on the other hand,
were distributed more generally in all fractions. Over half the Fe in the leaves
examined was in a form insoluble in 1 N HC1, presumably as Fe-hematin, Fenucleoprotein,
or other complex organics. Neither the total nor insoluble Fe nor
that soluble in water, ether, alcohol, 1. N acetic acid, 1 N NH4OH, 0.1 N HC1, or
1 N HCI was correlated with lime-induced chlorosis. Likewise, electrodialyzable
Fe could not be so correlated. The Fe extracted by 0.5 N HC1 was low in chlorotic
leaves; the HC1 had probably removed the Fe from an enzyme playing a role in
chlorophyll formation. Lime-induced chlorosis' is believed to be caused by a complex
of causes whose interrelations are not yet fully established. The data suggest that
a relatively high K level induces chlorosis by replacing Fe on the enzyme responsible
for chlorophyll formation, thereby inactivating the enzyme. There are 33 references.
The relation of some chemical and physico-chemical factors to the initiation
of pathological plant growth, A. J. RIKER. (Univ. Wis.). (Growth, 6 (1942),
Sup., 4. Symposium Devlprmt. and Growth, pp. 105-117, illus. 3).-This paper was
presented at the Fourth Symposium on Development and Growth. For studying
the factors associated with pathological plant growth, the author's attention has
been centered on crown gall (Phytomonas tumefaciens) and on comparable nonparasitic
growths. Among the important factors bearing on this problem and
studied intensively are those concerned with (1) loss in pathogenicity of the cellstimulating
bacteria induced by various amino acids, (2) recovery of their pathogenicity
in certain media and after ultraviolet treatment, (3) "oxygen hunger" of
plant cells, (4) changes in osmotic pressure which may cause swelling of the plant
cells, and (5) the presence of unusual quantities of enzymes and of growth substances-e.
g., thiamine, riboflavin, pantothenic acid, and biotin, (6) of bacterial
metabolites-e. g., NHs, phosphatides, phospholipids, and polysaccharides-that "irritate"
plant cells, and (7) of food materials in abnormal amounts. When some of
these and other important factors are present in unusual combinations and proportions,
living cells commonly begin to enlarge and multiply. While continuing to
examine individual factors, the investigator may well consider from the evidence
available that the initiation of pathological growth may be associated with an
unbalanced combination of some such important physiological factors. There are
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5064/m1/75/: accessed March 25, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.