122 PHYSIOLOGY [BoT. Absts., Vol. X, 



GERMINATION, RENEWAL OF ACTIVITY 



773. Jones, Henry A. Preliminary report on onion dormancy studies. Proc. Amer. 

 See. Hort.Sci. 17: 128-133. 1920 [1921].— The onion bulb, when harvested just after the top 

 has fallen, has a true dormant period. Yellow Globe Danvers onions grown from seed in 

 1919 were found to have a dormant period of 2-3 months, varying with the individual speci- 

 mens. The dormant period can be abbreviated and top and root growth initiated by trans- 

 versely bisecting the bulb. In dormant bulbs a light wounding of the basal end (root region) 

 will initiate root growth, but not top growth. Transversely cutting the bulb, — therebj' re- 

 moving the upper portion of the scales over the entire bulb, — may allow the escape of a gas or 

 gases toxic to growth or it may permit the entrance of the oxygen necessary for growth. Re- 

 moval of a longitudinal portion of several outside scales does not induce root or top growth. — 

 H. A. Jones. 



774. LopRioRE, G. Sulla germinazione dei semi verdi. [Note on the germination of green 

 seeds.] Staz. Sper. Agrarie Ital. 53:414-^18. 1920. — The present note deals with the phenom- 

 enon of chlorophyll retention by the cotyledons of various seeds. The author found that the 

 germination of seed of Faba, which presented a green pigmentation, was only 20 per cent as 

 compared to the normal behavior of normal seed. As a contrast to these findings the author 

 mentions some results which he obtained on the retention of chlorophyll by the cotyledons of 

 Fistacia. Some developing fruits were enclosed in black sacks in early spring while others 

 were left in the open, and all were examined in September when the seed growing in a normal 

 environment had attained maturity. A weight comparison of the 2 groups showed amarked 

 advantage in the case of the seed normally exposed. The seed of the darkened drupes when 

 placed in conditions favoring germination failed to germinate and actually decomposed. 

 Moreover, such seed, unlike normal seed, were lacking in true chlorophyll. Other analogous 

 cases are found among citrus plants, the seed of which are often found to germinate within 

 the fruit with the formation of true chlorophyll. The author limits himself, however, to the 

 enumeration of interesting cases. — A. Bonazzi. 



775. Parkin, John. Vitality of gorse seed. Nature 107: 491. 1921. — The author reports 

 that seed dormant in soil for 26 years germinated and grew to maturity. (Supplementary to 

 report in Nature 102: 65. 1918.)— 0. A. Stevens. 



TEMPERATURE RELATIONS 



776. Hooker, Henrt D. Pentosan content in relation to winter hardiness. Proc. Amer. 

 Soc. Hort. Sci. 17: 204-207. 1920 [1921].— The author advances a new theory of hardiness. 

 He suggests, "The pentosans, or rather some specific pentosan, function in the plant tissue 

 by holding water which is in the nature of absorbed or colloidal water, and that this type of 

 water actually does not freeze when the plant is subjected to ordinary winter conditions. 

 The greater water content of tender tissue as compared with hardy tissues would be due, 

 therefore, to an excess of free water. Though hardy tissues contain less free water they con- 

 tain more absorbed or colloidal water." — Shoots of hardy varieties of apple, like Wealthy and 

 Yellow Transparent, had higher pentosan content than the more tender varieties, like the 

 Missouri Pippin and Stajrman Winesap. In most cases the base of the shoot had a higher pen- 

 tosan content than the tip. Investigations on long, immature green shoots and short, well- 

 matured shoots of Ben Davis, showed that the latter had a much higher pentosan content. 

 Results of analyses on the currant and raspberry, also, show a correlation between pentosan 

 content and ability to resist low temperatures. Samples for analysis were taken on November 

 8, and December 2; the results are expressed in percentages on the basis of fresh weight. — 

 H. A. Jones. 



777. Kenoyer, L. A. [Rev. of: Coville, Frederick V. The influence of cold in stim- 

 ulating the growth of plants. Jour. Agric. Res. 20: 151-lGO. 1920 (see Bot. Absts. 8, Entry 

 378).] Jour. Indian Bot. 2: 154-155. 1921. 



