56 



THE AGKICULTURAL NEWS. 



February 12, 1916. 



EDITORIAL 



Head Office 



^S&M NOTICES. 



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Barbados. 



Letters and matter for publication, as well as all 

 -specimens for naming, should be addressed to the 

 ■Commissioner, Imperial Department of Agriculture, 

 Barbados. 



All applications for copies of the 'Agricultural 

 News ' and other Departmental publications, should be 

 addressed to the Agents, and not to the Department. 



1'he complete list of Agents, and the subscription 

 and advertisement rates, will be found on page 8 of 

 the cover. 



Imperinl ('ommissio')ier of FrancLs Watts, C.!M.G., D.Sc, 



AgricHlfurefor the West Indies F.I.C., F.C.S. 



SCIENTIFIC STAFF. 



Scieutific Assistant otui 



Assistant Editor W. R. Dimlop. 



Entomol<j(jisl H. A. Ballou, M.Sc. 



Mycologist W. Nowell, D.I 0. 



CLERICAL STAFF. 



Chief Clerk A. G. Howell. 



Assistant Clerl: M. B' Coimell. 



. Junior aerh W, P. P.ov.ll, 



Assistant Jnuior Clerk P. Taylor. 



Typist Miss*B. Robinson. 



A -t t t„ T> 11- f f A. B. Price, Fell.. Touiu. Inst. 



Assistants for ±^)mieattotis ■ t k n i ■ 



(Li. a. Corbin. 



^gricultunil Jfeiufi 



Vol. XY. SATURDAY, FEBKlAliV IJ, 191(i. Xo. 3(io. 



NOTES AND COMMENTS. 



•Contents of Present Issue. 



The editorial in this number refers, to the question 

 •of the measurement of .soil tilth b\' means of an appliance 

 ■of which we publish an illustration. 



Several articles appear in this issue concerning 

 fruit and fruit products, including cacao and coco-nuts. 



An illu.strated article will te tinunl on page tiH, 

 describing a parasite of the Hying fish. 



Insect Notes, on page .j!S, deal with grasshopper 

 contrt)!; under Plant Diseases, on page (}2. appears an 

 article on the spotting of oranges. 



Dutch Observations on Transpiration in the 



Sugar-cane. ' 



Nos. 4-4 and 4-") of Archie/ voorde Suikerindustrie 

 in I\edcrlandsl-- India for November 191.5, cont;iin 

 two interesting papers concerning stomata and trans- 

 piration in the sugar-cane. The first paper states that, 

 as might be expected, the stomata open in direct 

 sunlight and close io complete darkness. In very weak 

 light they slowly become partly open, and retain a small 

 opening during a long sojourn in such light. High tem- 

 perature causes the opening i)f the stomata even in the 

 dark, provided that the plant does not remain in the dark 

 too long. The influence of atmospheric moisture is nob 

 established with certainty: probably a high degree of 

 humidity is favourable to the openitig of the stomata. 

 When the plant is lull}' saturated with water the 

 opening is bigger. 



The observation that the stomata remains open in 

 direct sunlight, presumably' during the hot hours of the 

 day, is of interest in connexion with W. L. Balls' 

 observations in regard to the leaves of cotton, of which 

 the stomata were found to close during the middle hours 

 of the day. 



The second paper furnishes conclusions of a more 

 definite kind. 



The author found it convenient to work with cut 

 stems: their use is considered far preferable to that of 

 pot plants. It wotdd seem, however, that the use of 

 this material is open to objection when one comes to 

 apply the results obtained to sugar-cane plants grow- 

 ing under field conditions. As regards the conclusions 

 arrived at, it is stated that different varieties of 

 sugar-cane show themselves to differ as regards the 

 amount of evaporation at various hours of the day. 

 Those forms give the highest cane production in which 

 during the first hours of the day the evaporation is 

 strongest, with a rapid falling ott" afterwards. Thus, 

 not the kinds which retain about the same stomatal 

 opening the whole day, but rather those in which the 

 opening becomes smaller relatively early. In general, 

 transpiration and stomatal opening run parallel. 

 Nevertheless the maximum of transpiration generalK' 

 comes after the maximum of opening is already passed. 

 The number of stomata is of lesser importance in 

 relation to the .amount of evaporation. 



It would appear from the above that the author 

 regards a variety's capacity to regulate transpiration ;is 

 being correlated with cane production. In connexion 

 with this regulation of transpiration the author makes 

 no reference to the varying anatomical structure of cane 

 leaves which is responsible for the various curling 

 phenomena that must help to check the loss of moisture 

 tinder field conditions.'. 



The second paper is composed of the following 

 sections: (1) methods and material, (2) comparison of 

 certain varieties, (o) the relation between stomatal 

 opening and transpiration, f 4) comparison of cut stems 

 with plants in the ground. (•')) influence of intensity of 

 light on transpiration; ((i) the relation between the 

 amount of transpiration and the number of stomata. 



