Page:Journal of botany, British and foreign, Volume 9 (1871).djvu/183

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►riigtnal g^rficles.


By a. H. Church, M.A., E.C.S.,

Professor of Chemistry, Royal Agricultural College.

(Plate CXVII.)

Climate, season, soil, and manure, all have an influence on the amonnt of suo'ar produced in the root of the sugar-beet. On one occasion seed, saved from good Silesian sngar-beet, containing, on an average, about 13 per cent, of sugar, yielded plants the roots of which did not furnish more than one-fourth this percentage, for the\'had been too heavily dressed, with farmyard manure. In wet seasons, also, the roots may become very large, but the quantity of sugar they contain will not oidy be propor- tionately or relatively less, but may even be absolutely smaller in amount per root. Should, on the other hand, the season prove unusually dry and hot, a premature development, in the first year, of the flowering stem may take place, and this will be attended with a loss of sugar amounting to from one-eighth to one-fourth of the whole quantity present in the root. Yet, from the experiments of Coren winder (.Jahresbericht Agric. Chera. 1867, p. 127) the normal flowering of this biennial plant is attended by a complete consumption of its whole store of sugar. It is a singular fact that the seed produced in the first year from a sugar-beet plant of a good strain yields roots which only contain from 2"75 to 6"23 per cent, of sugar, according to the experiments of the chemist just named. Many other facts of physiologiral as well as agricultural interest relating to the occurrence and disappearance of sugar in this root have been recorded. It is, for instance, well known that in such beets as grow partly out of the ground the percentage of sugar in the exposed portion may be only one-third (3-7 per cent.) of that contained (11'2 per cent.) in the covered portion. Even in roots which have no tendency to leave the soil (a quality as valuable as the hereditary sugar-producing character), upper horizontal sections of a root contain rather less sugar than lower sections. Any variations which may exist in the saccharine richness of the several vertical zones of the root, reckoning from its axis to its circumference, do not appear to have been studied.

In the present notice I merely intend to record a series of experiments on the gradual development of sugar in beet-roots during the summer and autumn of the years 1869 and 1870. And I piu'pose, in giving the more complete experiments of the latter year, to exhibit them especially in rela- tion to the amoiuit of rainfall.

The first series of experiments was made in 18G9 with Silesian sugar- beet seed, kindly furnished me by Mr. James Duncan, of Mincing Lane, who has successfully established a beet- sugar factory, at Laveiduim, in Suffolk. Hoots taken up from the same experimental ground at Ciren-- cester at the undermentioned dates gave the following percentages : — September Stli, 1809 . 5'85 per cent, sugar. October 9th, „ . 8-58 „ „

November 3rd, „ . 9-43 „ „

24th, „ . 10-59

VOL. IX. [JUNE 1, 1871.] M

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