Chemistry of vegetable physiology and agriculture

1884 Journal of the Chemical Society Abstracts  
on Lemon-juice. By T. IJ- PHIPSON (Chem. News, 49, 198).- The author has observed that, when placed in a damp situation, lemons after a certain time develop Aspergillus gZawus, and coincidently emit a strong odour of ether. To explain this phenomenon, it is assumed that ethyl citrate exists in lemon-juice i n the same way as ethyl acetate exists in the saps of some plants, or i5 is suggested as probable that, under the influence of warmth and moisture, fermentation sets up, some of the sugar of
more » ... the ripe lemon is converted into alcohol, which then combines with the cit,ric acid to form the ethyl citrate; this is ultimately attacked by the A . glaucus, and its ethyl groups are evolved as ether. Influence of Light and Heat on PIant Development. By HELLRIEGEL (Bied. Centr., 1884, 123-126) .-The hemperature during which plant life proceeds is limited within narrow b o u n d a r k , there being a boundary €or each plant. Near the lowest limit, the growth is very slow, but with rising temperature life becomes more energetic until a certain temperature is reached when the life is most energetic ; this temperature is the " optimum," and does not of necessity coincide with the highest temperature at which life ceases. As a rule the optimum temperature lies between 20" and 40" ; a t 50" life is extinguished. In an analogous manner, light or darkness produces a definite effect, for altbough germination takes place better in darkness, no plant can grow without light, the plant is bleached, leaves and stems become abnormal, and the weight of dry matter diminishes. I n subdued light" assimilation proceeds but slowly, but is more rapid as the intensity of light increases ; the maximum of rapidity, however, is not coincident with the maximum intensity of the light. The combination of warmth, light, and moisture form a very important factor in the fertility of the plant, and in many cases i t is of more importance than manuring, &.c. The lowest limit of temperature at which the majority of seeds can germinate is &5", but a few can germinate at 0". Experiments were made on various seeds sown in soil kept a t different temperatures for 35-60 days. Most of the ordinary seeds germinated below 4", and winter rye was able to grow a t 0". Wheat germinated and grew a t O", but hardly so rapidly as rye. Barley and oats required a temperature of 2" to develop, for a t 0" they only 856 ABSTRACTS OF CHEMICAL PAPERS. developed the radical, and no plumule. Maize required a temperature of 8.7". Vetches only demanded a temperature of O", whilst peas and clover required 2" ; beans and lupines, 3", for the development of the plumule. The lowest temperature for carrots was 3" ; for turnips, 5" ; and cucumbers showed no signs of germinating a t 8.7". Linseed developed the radical alone a t 2'. E. W. P. Influence of Weather on Vegetation. By F. HILDEBRAND ( B i d Cerztr., 1884, 138).-An account of the abnormal growth of plants during the remarkable winter of 1882. Here we find annuals floweri n g and growing during the secoud year. Biennials, as Digitalis purpurea, become shrub-like, plants which flower before their leaves, appear flowering afterwards, and vice vers8. E. W. P. Effect of Water holding Sodium Chloride and Zinc Sulphate in Solution on the Soil and on Plants. By F. STORP anti others (Bied. Centr., 1884, 76-87) .-Solutions of sodium chloride cause the loss of greater amounts of sulphuric acid, lime, and potash from soils, the atronger the solution. The action of this salt as a manure is to decompose the more stable compounds of the soil, but should the amount applied to the land be great, then an excess of calcium and magnesium chlorides are formed, and if in the presence of humus, free acid. To avoid this danger, the manure should be applied only in small proportions, and at a date long previous to that when vegetation should commence. The influence on the composition of grasses is also considerable, for the percentage of alburninoids, dry matter, and fat decrease .as the sodium chloride increases. Very dilute solutions ( &a per cent. j aid germination; but stronger arrest the process completely. Soils can absorb as much as 80 per cent. of zinc suIphate from its solutions, and at the same time lose calcium, potassium, sodium, and magnesium compounds ; moreover, the loss of potassium increases with the strength of the zinc solution ; in the presence of calcium carbonate, zinc sulphate is converted into the carbonate. The preservative action of zinc is exemplified in the neighbourhood of zinc works, where the dust, has settJed on the pine-needles, and completely prevented their decomposition, but when huxnic acid is in solution, then the zinc combines with it, and free sulphuric acid is formed. To a n extent similar to that whioh is found in the case of sodium chloride, zinc sulphate affects the composition of growing grasses, and the ash may contain as much as 2.3 per cent. of the oxide: some plants, as the oak, are but little afFected, either by zinc or sodium. The influence on germination is remarkable, for i n the dark no harm is done, but in the light it is arrested and the life destroyed; this destructive action does not seem to affect fungoid growths. Experiments in which water containing the two compounds under consideration was allowed to flow over soil, gave results similar to those already mentioned. J. Konig repeated these last experimmts, adding ferrous sulphate, and found that whereas sodium and zinc sulphate reduced the dry matter in the crop, ferrous sulphate raised it; this 857 result is attributed to the separation of the acid from the base, the acid rendering other material for the plant soluble. Respiration of Leaves in the Dark. By G. BONNIER and L. MANGIN ( C m p t . rend., 98, 1064-1067) .-Comparative experiments respecting the oxygen absorbed and the carbonic anhydride evolved in the dark by the leaves of various species of plants show that the ratio between these two quantities is constant, whatever the temperature, and although the amount of carbonic anhydride evolved increases rapidly with the temperature, the amount of oxygen absorbed increases in exactly the same proportion. The ratio is approximately unity for certain species, e.g., Euonymus japonicus, Bsceclus hippocastanum, whilst for other species, e.g., Pinus pinaster, it is considerably less than unity. The authors have previously shown that the ratio between the carbonic anhydride evolved and the oxygen absorbed is independent of the pressure of the oxygen and of the proportion of carbonic anhydride in the surrounding atmosphere, and it is evident that these.two E. W. P. processes of absorption Lnd evdution are most intimately connected. C. H. B. Respiratory Combustion. By P. SCH~~TZENBERGER (Compt. rend., 98, 1061--1U64).-The experiments described in this paper were made with a view to ascertain the effect of the presence of certain organic substances on the respiratory combustion of yeast cells. Similar flasks were filled with equal quantities of water saturated with oxygen, an equal amount of yeast was added to all of them, and then known weights of the particular substances employed, and after the lapse of a given time, the amount of oxygen which had been absorbed was determined by titration. The organic substances added were different varieties of sugar, mannitol, various alcohols, glycerol, acetic, butyric, tartaric, and other acids, sodium acetake, Rochelle salt, and other salts, amido-compounds, hydrocyanic acid, and chloroform. Some of these substances have no appreciable effect on the respiratory combustion, others, such as hjdrocyanic acid and chloroform, check it or retard it considerably. Invert sugar, ethyl alcohol, and sodium acetate accelerate the absorption of oxygen in a very marked manner, whilst glycerol and the higher homologues of ethyl alcohol exert a similar but much less energetic action. Methyl alcohol has little or no influence on the process. The effect of the most active substance is equally well observed with fresh yeast, or with yeast which has been exhausted and washed, but the effect of the less active substances is more clearly observed when the exhausted yeast is employed, because the substances naturally present in the fresh yeast are more combustible than those which are added, The results show that ethyl alcohol is particularly apt to undergo slow physiological combustion, its power in this respect being equal to that of invert sugar. It is possible, indeed, that the invert sugar is first converted into alcohol, and then consumed, and if this be true, ethyl alcohol and the alkaline acetates must be classed in the first rank amongst those substances which undergo combustion in the living organism.
doi:10.1039/ca8844600855 fatcat:yv6oj5ttsbdvvbhx3ba5ew34wi