Stopes and Fujii, The nutritive relations of the surrounding tissues etc. ]_]_ 



The protein grains have a very similar distribution, and in the 

 general endosperm cells which were packed with starch grains ? 

 there were also almost as many large protein grains (see 

 fig. 8, s.). At the time liowever when the starch grains were 

 disappearing from the egg cell, the large protein granules remained 

 in it. In Ginkgo as with the Cycads, it is most unlikely that 

 protein grains travel as such from any of the surrounding cells into 

 the egg, bnt are probably converted to some soluble simpler forms 

 easier for transit by the action of Proteases 1 ) and are re-deposited 

 in the right place in a higher form for the immediate use of the 

 growing egg or for temporary storage. 



Pin us. 



Between Pinus and the two gronps just treated, the chief 

 differences lie in the size of the ovule, which is relatively small in 

 Pinus, and in the (perhaps consequent) very different relations 

 between the state of development of egg and ernbryo, and the date 

 of deposition of nutritive substances. To describe in detail chiefly 

 from work on P. Cembra, montana and sylvestris, we find the case 

 is as follows. 



In very young ovules in which the archegonia were not present, 

 starch was already deposited in considerable quantities in the tip 

 of the nucellus, but was intirely absent from the endosperm tissues, 

 in which however there was much sugar (giucose). After the first 

 appearance of the archegonia, and all through their earlier stages 

 this was also the case. The jacket cells of the archegonium are 

 early differentiated and have extremely large nuclei, but no starch 

 has been observed in them in any of these younger stages. 



In the uext important stage (the nucleus being in the middle 

 of the egg) the cytoplasm of the egg cell had become very 

 vacuolated with usual vacuoles, while it was still but little granulär. 

 From ovules in such a stage of development in P. Cembra material 

 was collected eveiy 3 hours and examined in a fresh condition, and 

 at the same time some was fixed immediately. At 6 a.m. there were 

 considerable numbers of small starch grains lying scattered in the 

 cytoplasm of the egg (cf. fig. 9). Some grains were still present at 

 9 a.m., but in far fewer numbers, and by noon the cytoplasm of the 

 egg was devoid of starch. In the afternoon the starch was observed 

 at 3, 6 and 9 in small quantities. Quite similar results were 

 obtained with P. sylvestris in ovules in a similar stage. At 1.30 

 midday there was no starch in the egg cells, while at 6 p.m. there 

 were many t'airly big grains scattered all through its cytoplasm. 



This stage of development was passed over in a few days, and 

 in P. sylvestris alter 5 days the egg cytoplasm had become very 

 granulär and large numbers of true "protein vacuoles" were present. 



x ) Vines, S. H.. „Tryptophane in Proteolysis". (Ann. of Botanv. Vol. XVI. 



1902. p. 1 to 22.) ,. Proteolyse Enzvmes in Plants". (Ann. of Botanv". Vol. XVIi. 



1903. parts I and II.) ..The Proteases of Plants". (Ann. of Botanv. Vol. XVIII. 



1904. p. 289 to 316.) 



