132 Physiologie der Zellen, Gewebe und Organe. 



The trials reported upon in this paper show that a distinct advantage fol- 

 lows the use of heavy and large seed. Plants grown from large seed possess 

 more leaves of greater surface area and hence have greater assimilative powers. 

 The weights and sizes of plants compared at different stages of growth show 

 that the large seeds produce heavier plants. Earliness and improved quality are 

 also a result of seed selection. The seeds used in the experiment were sweet 

 pea, hubbard squash, sweet pumpkin, lettuce, spinach, parsley, radish and bean. 



Pearl. 



334) Carner, W. W., Allard, H. A. and Foulbert, C. L., Oil Content of 

 Seeds as Affected by the Nutrition of the Plant. In: Journ. Agr. 

 Research, Vol. III, No. 3, S. 227—249, Dec. 1914. 



Experiments with soy beans have shown that, except for the period im- 

 mediately following blooming and that directly preceding final maturity, there 

 is a fairly uniform increase in oil content, both relative and absolute, throughout 

 the development of the seed, and no evidence was found that there is a critical 

 period of very intense oil formation at any stage of seed development. Tests 

 with cotton likewise indicate that the increase in oil proceeds somewhat more 

 rapidly than the increase in the weight of the seed. Maximum oil production 

 in the plant requires conditions of nutrition favorable to the accumulation of 

 carbohydrate during the vegetative period and to the transformation of carbo- 

 hydrate into oil during the reproductive period. As a special phase of this rela- 

 tionship between carbohydrate supply and oil formation in soy beans, it was 

 found that when the normal distribution of the vegetative and reproductive plant 

 parts was modified by partial defoliation (50 to 60 per cent.) the yield of beans 

 was decidedly reduced, but the size of the beans and their oil content were only 

 slightly affected, except in the case of an early-maturing variety. On the other 

 hand, the removal of a portion of the blossoms or young pods caused a notable 

 increase in the size of the beans allowed to develop, but did not materially affect 

 the percentage oil content. There is always lack of uniformity in the size of the 

 seed from an individual plant; but it was found that there was no correlation 

 between the size of the seed and the percentage of content of oil. No corre- 

 lation was found between the date of planting and the size of the seeds or their 

 oil content. These properties appear to be influenced more by the character 

 than by the length of the growing period. Different varieties of soy beans grown 

 under the same conditions showed marked differences in size of the seed. Although 

 different varieties of cotton showed decided differences in the size of the seed, 

 there was very little difference in the percentage of oil content. The different 

 varieties of soy beans did not respond alike to changes in seasonal conditions. 

 It is concluded that under practical conditions climate is a more potent factor 

 than soil type in Controlling the size of the seed and its oil content, probably 

 because those conditions of the atmosphere which constitute the climate largely 

 control the corresponding conditions of the soil. Within ordinary limits the 

 relative fertility of the soil appears to be a minor factor in influencing the size 

 of the seed and its oil content. Pearl. 



335) Chandler, W. H., The Killing of Plant Tissue by Low Tempera- 

 tur e. In: Research Bull. No. 8, Missouri Agr. Expt. Sta., S. 143 — 309, 

 Dec. 1913. 



This paper reports the work of an extensive investigation on the killing of 

 plant tissues by low temperature. The term sap density in this publication re- 

 fers, not to specific gravity, but to molar concentration. The term freezing 



