Fray Bentos meat factories (bone meal, bone ash, guano) in comparison with basic slag and superphosphate.

A special experiment was conducted on plots of 63 sq. yards with rye, for the comparison of bone meals of various degrees of fineness:

These results confirm the usefulness of phosphatic manures for the soils of Uruguay. The differences observed are within the limits of experimental error. Only coarse bone meal has given, during the first year of the experiments, inferior results, thus corroborating the evidence already obbtained in other places as to the influence of the fineness of the meal used.

AGRICULTURAL
BOTANY.
CHEMISTRY

AND
PHYSIOLOGY

OF PLANTS

654 - Calcium as an Antitoxin to Certain Nutritive Salts in Water-Cultures of Peas and Lupins. ROBERT, C. in Comptes Rendus de l'Académie des Sciences,

Vol. 156, No. 11, pp. 915-918. Paris, March 17, 1913.

Pea seedlings, after having been started in pure distilled water (i. e. redistilled over glass) were transferred to the following solutions:

All such plants immediately ceased to grow and appeared to find their medium thoroughly toxic, but when calcium sulphate was added in the proportion of 500 mg. per litre, the toxic effect was completely neutralized; nor did it appear when the seedlings were transferred to a solution of calcium sulphate alone.

The following figures were obtained in two sets of experiments:

The experiments lasted 12 days and the temperature varied from 20° to 25° C.

The growth was practically the same whether the calcium sulphate was supplemented by other salts or not, and it would seem, therefore, that salts of potassium, magnesium, and ammonium do not play an important part in the nutrition of the pea seedling during its early development.

The antitoxic effect of calcium with regard to copper was also shown by growing a set of plants in ordinary copper still water, when the following results were obtained:

The experiments were repeated with white lupins, which proved even more sensitive than the peas to the toxic action of the nutritive salts; but, on the other hand, wheat and maize gave far less decided results, and with them potassium salts in the concentrations mentioned above hardly appeared noxious at all. The investigations are being continued.

655 Modifications and Mutations of Tuberous Plants. — LABERGERIE in Bulletin des Séances de la Société Nationale d'Agriculture de France, Vol. LXXIII, No. 2, pp. 157-161. Paris, 1913.

The writer mentions his previous investigations and those of Eckel and Verne on the mutations which have been observed to occur in Solanum Commersoni. These investigations were made in Poitou in 1912 and under unfavourable conditions from the point of view of insolation.

Nevertheless, the following points are worthy of notice: 300 plants were grown in different nutritive media, ranging from pure sand to arable soil, with the addition of 5, 10 and 25 per cent.in weight of a fertilizer consisting of the following substances:

The tubers which showed a tendency to mutation in preceding years, when put into pure sand evinced clear signs of retrogession to the wild species, with abundant and prominent lenticels and rough skin; the flowers reassumed their very long styles, their deeply divided corolla, and blunt sepals. While on the other hand forms in contact with S. tuberosum, such as Early Rose, Merveille d'Amerique and Violet Commersoni 1-01, maintained their modifications, which were much accentuated by the application of the above-mentioned fertilizer.

Another series of experiments was carried out with wild S. Commersoni collected in 1911 and compared with similar tubers gathered in 1910, which had been kept dry. The fertilizer had no effect upon the former, beyond causing a variation in the yield; but the tubers of 1910, which had got very dried up, presented the following characters:

Pure sand: wild type maintained.

With 5% fertilizer: wild type maintained with slight modification.

PLANT BREEDING

The writer considers that, given a season of full sunshire, the modifications would give rise, as in 1901, 1904, 1906 and 1907 to complete mutations. In any case, the results leave no doubt as to the great effect of vicinity increased by the application of manure.

A third set of experiments showed that 1.1 per thousand of manganese sulphate causes the medium to be infertile and entirely suppresses the development of tubers; with 5 per cent. fertilizer and 0.55 per thousand of managanese sulphate, the tubers were very irregular and few in number; with 25 per cent. of manure, the same amount of manganese allowed a more abundant development of tubers, but these were very irregular if the plants producing them were derived from much modified tubers.

The facts may be summarized as follows:

1) Plants in contact preserve their clear tendency to mutation, and fertilizers increase this action to the point of making the crops resemble in a marked degree the ordinary S. tuberosum.

2) Any drastic treatment of the tubers, such as prolonged desiccation, facilitates the action of the fertilizer, which, however, has not so much effect as when it is used in conjunction with contact action.

3) Large amounts of manganese paralyse the property of tuber production, while the effect of a small dose is yet to be determined.

656

Influence of Radio-activity on Germination. · PETIT, G. and ANCELIN, R.: in Comptes Rendus de l'Académie des Sciences, Vol. 156, No. 11, pp. 903-905. Paris, March 17, 1913.

Seeds of rye grass, wheat and maize were germinated between sheets of damp blotting paper. In one set the water used for damping had a radio-activity of 0.089 mg.-min. per litre, while in a set of controls ordinary water was employed. In each case the radio-active water had a remarkably stimulating effect on the grains, though this effect did not become apparent till about the twelfth day after the commencement of the experiment.

657

On Cleistogamy in Rice (Oryza sativa) and the Possibility of Cross Fertilization. FARNETI, RODOLFO in Atti dell'Istituto Botanico dell'Università di Pavia, Series II, Vol. XII, pp. 351-362, plate XIV. Milan, 1913.

The writer has been able to observe that the pales of rice never open, before, during or after the dehiscence of the anthers. Consequently the natural production of hybrids is impossible, even as a chance occurrence. All the varieties and forms in cultivation must have sprung from mutations. The great number of these may be explained by the marked diversity in the conditions of surroundings, climate and cultivation to which rice is subjected.

Rice is therefore a cleistogamous plant, but is exceptional among such in possessing flowers of only one type, with perfectly formed gynoecium and androecium. It is cleistogamous in that no natural internal pressure can open the flowers, as this is mechanically prevented by a hinging of the edges of the two pales throughout their length. This is perhaps a unique type of cleistogamy and presents much interest; it should be noted that

Leersia oryzoides, which is one of the few other cleistogamous grasses, and is a marsh plant closely related to rice, presents two types of flowers as is usual in cases of cleistogamy.

It is well known that climate and special conditions tend to modify the mechanism of pollination; it was therefore interesting to find out whether cleistogamy occurs in all varieties of rice and in all places where it is grown, or whether exceptions occur as in other cleistogamous plants, not excepting the species of Leersia. An examination was therefore made of 23 varieties of rice grown in Japan, sent direct from Nisigura, and of several varieties indigenous in Italy or introduced at various dates from abroad: not a single exception was found.

The cause of the cleistogamy of rice is presumably hereditary. Oryza sativa is a native of river banks and flooded land in Indo-China; in this country during its period of growth torrential rains occur daily, accompanied by flooding of the rivers. If the rice flowers opened, their fertilization would certainly be interfered with, if not prevented.

As natural hybridization is excluded, the writer attempted to find out whether there was any possibility of making artificial cross-fertilization. The practical results obtained by crossing in many cultivated plants, and especially in cereals, are such as to encourage any attempt at hybridizing rice, either by cross-fertilization or grafting. The production of hybrids by the latter means is, however, much disputed. With rice it was attempted as long ago as the beginning of the 18th century by Gianverardo Zeviani of Verona; he was the first to attempt grafting on rice, and indeed on any gramineous plant, with the idea of reinvigorating the species, which he believed to be degenerate. But the grafted plant did not give good results.

In the writer's experiments on hybridizing by artificial cross pollination, all the flowers artificially opened, whether or not the stamens were destroyed, remained unfertilized, while all those not operated on set seed.

He believes the failure was due not to lack of skill, or to the damaging of the flowers, but to other causes which remain to be investigated. He suggests a lack of sufficient moisture of the air within the opened flowers, as evaporation within the naturally closed ones would obviously be very limited. The experiments are to be repeated, and the plants dealt with will immediately be placed in a damp atmosphere, either under bell-jars or in forcing houses.

If the sterility of the flowers artificially opened but not mutilated was due solely to this cause, artificial crossing of rice, though very difficult, cannot be considered impossible. All will depend on the skill and patience of the operator.

658 Particulate Inheritance.

BLARINGHEM, L. Sur l'héredité en Mosaique. — IV Con

férence Internationale de Génétique, Paris, 1911, pp. 101-131. Paris, 1913.

In his works published in 1862-63, Charles Naudin pointed out that the characters of two parent species are not always uniformly distributed in all parts of their hybrid offspring, but that sometimes visible patches of the one parent occur side by side with visible patches of the other parent,