Evening star., 1951-08-17
Plant Vitomin Content
Varies on Temperatures
Differences Up to 500
Found in Detailed Study
By Thomos R. Henry

Differences of as much as so per cent
in the vitamin content Of vegetables,
depending on the temperature at which
they are grown, have been found in
recent experiments reported by DR.. r. q.
GuStafSon.
He used ten vegetable species which
were analyzed for their content Of the
three most essential B vitamins-thi-
anime, riboflavin and NICOTINE acid. All
these are necessary for health and even
life itself. Two temperature ranges were
used in the greenhouse-10 to Is de-
grees and % to 80 degrees centigrade.
Prior to analysis the plants were kept
at these temperatures for at least week
and usually for several weeks. 1t was
found that responses varied widely.
Plants which make their best growth
during the warm part Of the summer
had a higher vitamin content when
grown at the higher temperatures. This
was true of tomatoes, beans and soy
beans. Plants like cabbage, broccoli and
spinach, which grow best in the cooler
part Of the summer and in spring and
fall, tended to have q higher vitamin
content when grown at the lower tenn
peratures.
Exceptions Listed.
Clover, peas and wheat were interme-
diate between these groups. With these,
in general, the lower temperature tended
to produce higher vitamin content, but
there were exceptions. The essential
ribof1avin was consistently higher at the
lower temperature range.
DR.. Gustafson reports differences as
high as 81 per cent and they often ran
from Is to 80 per cent.
There are two possible explanations.
One is that more vitamins are produced
during the fast growth that comes with
higher temperatures. The other Is that
they are lost more slowly at lower tenn
peratureS.
The finding should be Of considerable
value to the housewife, according to the
Journal of the Nutrition Foundation,
because she can make use of vegetables
in the diet of her family during seasons
when their vitamin content Is high. 1t
may be of even more value to the plant
breeder. For some years there have
been programs at agricultural research
stations all over the country to produce
new species of higher vitamin content.
reported. Such reports, however, are
of little value unless the seasons when
the plants were analyZed are taken into
consideration.
Data Analysed.
Over the past decade large body OF
data has accumulated on the vltamln
content of wheat, corn and oats. This
data now has been given extensive sta
tistical analysis, from which it appears
that the thiamine and riboflavin con-
tents Of wheat, corn and oats, the
NICOTINE acid content Of corn and oats.
and the pantothenic acid content OF corn
vary considerably with the harvesting
season.
There also is considerable variation
with the fertilizer used. Phosphorus
alone increased the thiamine content.
nitrates increased the NICOTINE acid and
nitrates and potash in combination In
creased the pantothenic acid content OF
wheat. In corn potash decreased the thl-
anime content, as did dry season COM
pared with a normal season. Wheat
grown in a normal year had more ribo-
f1avin than that grown in wet year.
Exactly the reverse was true for oats.
Such findings, it is stressed, have no
more than opened the door for @ very
great field of experimentation which
NAV have considerable implications for
human welfare It is quite possible that
other facts besides temperature ana
fertilizer have even greater effects on
the amounts of various vitamins present
in food products.