~42-

with conifers Sparrow (21) observed that doses as low as 3 Yr

and 4 r per day caused death of Pinus rigida after six years
of exposure
plants,

(total cumulative dose,

however,

cumulated dose,

about 8000 r).

Many

were dead or dying at doses much below this
and some visible damage was observed at doses

below 3 r per day.
Observations made in February 1956 in the Marshall
Islands by Fosberg

(9,1C) also suggest possible radiation

damage to plants twenty-three months after an incidence of
high level radioactive fallout.
the

land plants

(Guettarda gpeciosa,

maritima and others)
the

He found severe damage in

at Gegen Island,

Cocos nucifera,

Suriana

Rongelap Atoll,

where

"total radiation dose to infinity” was reported to be

3360 r.
lower,
species

Where the levels of radiation were 10 to 100 times
little or no damage was observed.
(Guettarda,

Lepturus

repens,

However,

some

and Fleurya ruderalis)

appeared to be normal at Kabelle Island where the radiation
level was high

(total dose 1824 r).

Cordia subcordata,

Other species

(Suriana,

Cocos nucifera and Pisonia grandis) were

abnormal in appearance at islands where the levels of radio-

activity were lower.

Fosberg suggested that some species of

plants were more susceptible to ra@iation than others.

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