228 EXPEREMENT STATION RECORD. 



Osmotic pressure in potatoes, M. A. Braxnon {Bot. Gaz., 56 (1913), No. 5, 

 pp. 433-438, figs. 4). — This article has been previously noted (E. S. R., 29, 

 p. 133). 



Imbibition studies on seeds of Avena sativa, F. Plate (Atti R. Accad. 

 Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 22 {1913), II, No. 8, pp. 133- 

 I4O). — Summing up studies carried out with beans in solutions of several acids, 

 bases, and salts, the author claims that no exclusive part in imbibition is played 

 by either cations or anions in this connection, and that most of these chemical 

 agents promote germination even in high concentrations. 



Influence of moisture relations on species of Pinus, B. Hergt {Mitt. 

 Thuring. Bot. Yer., 30 {1913), pp. 129, 130; ahs. in Bot. CentU., 123 {1913), 

 No. 9, p. 220). — The author notes a striking limitation in growth, during the 

 dry year, 1911, of needles of P. sylvestris and P. nigra as compared with the 

 1912 growth on the same branches. 



Defoliation: Its effects upon the growth and structure of the wood of 

 Larix, A. G. Haepek {Ann. Bot. [London^, 27 {1913), No. 108, pp. 621-642, 

 pis. 2, figs. 2). — A study has been made of trunks of larch trees that have been 

 recently defoliated by the larvae of the larch sawfly. 



It was found that premature defoliation resulted in a greater or less degree 

 of starvation, which was shown by the quantity of the growth and the structure 

 of the wood formed. If starvation is severe, growth may cease over certain 

 parts of the cambium mantle, while other regions are still active. The investi- 

 gations showed that in larch trees killed by defoliation, growth ceased entirely 

 at the base of the tree a year or more before the tree died. The first visible 

 effects of defoliation in the structure of the wood is said to be the reduction 

 of the proper thickening of the walls and cells of part or all of the zone 

 of autumn wood, without much decrease in the breadth of the whole ring. 

 The outermost cells of the autumn wood may have their walls unthickened 

 on account of the lack of food supply at this period of the year. Abnormally 

 formed resin ducts were found and they are considered possibly a pathological 

 effect of starvation. 



Root secretions of plants, E. A. Mitscherlich {Landw. Vers. Stat., 81 

 {1913), No. 3-6, pp. 469-4^4)- — This continues a somewhat controversial dis- 

 cussion by the author (E. S. R., 28, p. 721), Rodewald (E. S. R., 28, p. 722), 

 and Pfeiffer et al. (E. S. R., 28, p. 518). regarding the existence and expression 

 of a law of minimum. 



FIELD CEOPS. 



[Test work with forage and field crops], M. Calvino {Estac. Agr. Gent. 

 [Mexico^ Bol. 66, 1912, pp. 3-23, 41-48, 67-72, pis. 22).— Trials in the production 

 of forage crops are here reported. 



Oats and white mustard grown together produced at the rate of 64,660 kg. 

 of green fodder per hectare (28.77 tons per acre) in 3 months, and Thousand- 

 headed kale yielded at the rate of 68,000 kg. in 5 months. Dactylis glomerata, 

 Plileum pratense, and Bromus inermis made satisfactory growth, Dactylis 

 being especially luxuriant and reaching 1-^ meters at the flowering stage. 

 Notes are given on variety tests of turnips and the value of turnips and oats 

 sown together for forage. Tests of Trigonella fosnum-grwcum, Medicago 

 arJ)orea, Hedysarum coronarium, and Onohrychis sativa are also mentioned. 



Variety tests with potatoes produced yields ranging from 2,782 to 13,000 kg. 

 per hectare. Whole' tubers gave much better results as seed than cut tubers. 

 Directions for seed selection of potatoes are given. Notes on the value, culti- 

 vation, harvest, and uses of buckwheat are given, as are also variety tests 

 in which the yields ranged from 1,800 to 2,800 kg. per hectare. 



