STUDIES IN POLLEN, WITH SPECIAL REFERENCE TO LONGEVITY 771 
exhaustion of stored food. Since more favorable results were obtained 
in normal air than in pure oxygen, it would appear that normal atmosphere 
is more favorable to the prolongation of viability. 
TABLE 15. AntrRRHINUM PoLLEN STORAGE IN PuRE OxyGEN COMPARED TO STORAGE 
IN Arr (10°-22°C.). 1917 
Flowers Seed capsules Percentage of Average length of 
pollinated developed germination pollen tudes 
Age 
In In In In In In 2 
air oxygen air oxygen air oxygen In air In oxygen 
Days Number | Number | Number | Number | Percent | Per cent 
Ussonenaoce 9 3 8 3 ] 20 65 Medium-long..| Long 
THe oo.6 oc G00] |ho Bio Raion PERG CleRERCICI RCC Remeic nea (ee SS aostys SOM) a aera Ios ete Ol lao ha oOo maa G 
2S eter || dane. oss GS ery re SS | Wigton cee CLO) reece mcr ene es Medium-long 
35 Uf 52s oe Geshe Seats: 4OP Si toes Short—long es |Peeee eer ee 
CS ane tater oboe ete Grae aeisca CTs al geen cree GOR eRe asic eter Medium-long 
56 1 ee eee Tue hiokaae eee AORN Maes teas Medium—longs|haeee eee: 
OSE iis siete leet By at ie ie Sie | [ba ereties LOT fll eae olsen eorees Medium-long 
1 he ee eee ARES es 035s | des ee eens ee SOR SU Me ets ce Medium=long lt. 50.0 an onne 
UD Geter eee oe eevee Siane, svecoue Gir | ena BP) | eee aes GAO fencing cece eee Medium-long 
WAQU Ss Hea Ds cael eee a Piel eee aa SO Rea See me Short longs |e eee eee 
ee era ee eel esse ots Bi Ol egabos 2 Be<ete SO ieee ee ara eset Short-long 
TGS oboe. oo susts| |) terale easel eee | Ogres |keeress OFT Reena HOLS eon thee eee 
IBV. 2 co clo sollte a Een Caer Netassovatos Meccan SA) aedrad eee TCO ee ane Poe eee Short-—medium 
13s cto’ dis om bal leo here aoe eee | ORE ere (Oro itor |) Conuiene oes eenrd loa meeooid oue ac 
(iO); sane eee C3 a (ae ee Ola | eras 50* 10* Short—medium.| Short. 
| 
*Piece of stigma added. No germination occurred in absence of stigma. 
From the results of all these storage experiments, it may be con- 
cluded that Antirrhinum pollen remains viable longest at low temperatures. 
Moisture conditions, provided they are not too high, are not important. 
Storage under low atmospheric pressures does not yield good results. 
Pollen remains viable longer in normal atmosphere than in pure oxygen. 
There is some evidence that an atmosphere of pure carbon dioxide or 
one containing large percentages of ‘it favors longevity. The results 
obtained in 1917 were better than in previous years, a fact which may 
be due, in part, to the sealed glass tubes used as storage containers, but 
which is more probably due to the greater virility of the pollen produced 
in 1917. The author wishes to emphasize the fact, mentioned by other 
investigators (Kellerman, 1915), that pollen varies greatly. Many data 
had to be discarded because of this uncontrollable factor. 
The writer has demonstrated that Antirrhinum pollen can be stored 
a longer time than forty-three days, which was the limit reported by 
