摘要:

Summary.Swamp kauri was compared with normal kauri pine wood but no very decided differences between them were discoverable.No definite structural differences were noted in the microscopic examination.The shrinkage in swamp kauri was found to be less than in normal kauri when losing moisture under the same conditions.No differences in hygroscopicity were noted.The density of the wood substance of swamp kauri is the same or slightly less than that of normal kauri pine.No mechanical tests were made.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07019.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.A series of correlation studies has been carried out between the seed characteristics and early growth data of a number of Record oats samples; many coefficients of correlation obtained gave values of no biological significance. The influence of “outlying” readings had to be carefully considered as the number of readings was limited. For this purpose dot charts were employed as well as mathematical coefficients.The results can be summarised as follows:1Generally the total germination figures in a sand test were correlated with field establishment, but within the narrow germination range 85–100 per cent. no correlation with establishment was found.2The amount of available food in the seed as measured by the average dry weight of the caryopses influenced the size and weight of the seedlings produced.3The moisture content of the grain was negatively correlated with the rate of germination, indicating that samples stored with a high water content did not germinate well.4The percentage husk bore no relation to germination.6Ten weeks after sowing the mass of the plants obtained from a given sowing depended primarily upon the number of plants established. Although tillering was well advanced plants possessing additional space did not compensate for low establishment figures at this stage by increased growth.6When the grain was heated for 15 minutes at 75°C. those samples containing a high moisture content suffered more than well dried samples. Indications were also obtained that the following type of sample was particularly susceptible to such injury—artificial heating—(a) a rapidly germinating sample,(b) a thin‐husked sample,(c) a sample with

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07020.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.In a series of pot experiments on potatoes grown in an acid soil artiftcially infected with the wart disease fungus, treatments with sulphuric acid and various combinations of sulphur and calcium carbonate, yieldmg a wide range of soil reaction, gave almost complete freedom from infection when the acidity of the soil had been raised to a very high value (pH 3.4 or less).Heavy dressings of calcium carbonate, alone or with sulphur, giving a soil reaction ofpH7.5 or more, also reduced infection.The fact that partial and even, in one experiment, complete suppression of disease was obtained at lower acidities, where the effect on the disease was not closely related to the degree of acidity, supports the tentative conclusion already drawn from field experiments that sulphur in controning wart disease does not depend entirely on its effect in raising the acidity, but has also some other mode of action. Whether this toxicity which sulphur exerts apart from its effect on the acidity can be enhanced sufficiently to be of any practical value requires further investigation.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07021.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.1Hydrogen peroxide, when added in the form of superoxol to an aerated yeast molasses mash, is very toxic to the yeast, greatly inhibiting or entirely stopping yeast growth, fermentation and inversion.2The yeast yield without aeration in a mash of this kind is greatly diminished, while the other changes are only shghtly inhibited, the total loss of solids bekg appreciably greater than with aeration.3If thepHchange in such an aerated mash is allowed to progress normally, a marked fall from 7.0 to 2.0 is observed, apparently due to the formation of organic acids, and to removal of ammonia from the ammonium salts.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07022.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.1Concentrations of 0.3 and 0.1 gm. of hexyl resorcinol per litre completely inhibit yeast growth and fermentation. Concentrations of 0.01 and 0.005 gm. only slightly inhibit.2Invertase action is not affected in the presence of 0.3 gm. of hexyl resorcinol per litre of mash.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07023.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.Observations during February, 1927, are recorded on nominally healthy potato tubers sprouted indoors in the laboratory of the Seed Testing Station, East Craigs, producing short diseased shood showing probable primary infection ofPhytophthora infestans. At the end of the month probable cam of secondary infection occurred.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07024.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.Samples of soil were taken from six of the plots of Barn Field on the farm of the Rothamsted Experimental Station, and the Insects and other Invertebrates found therein are recorded together with the approximate depth at which they occurred.On these plots one receives no manure, one superphosphate only and one ammonium salts only, while of the other three, all of which receive dung, one receives superphosphate and potash, and another ammonium salts in addition.The total number of Insects and other Invertebrates per acre in the undunged plots were 1,208,000, 1,410,000 and 1,734,000 respectively. Of these 673,000, 999,000 and 1,424,000 respectively were Insects. Similarly in the dunged plots the total numbers of Insects and other Invertebrates per acre were 12,948,000, 9,448,000 and 10,516,000 respectively, and of these 2,323,000, 2,215,000 and 4,677,000 gespectively were Insects.Each sample was taken in five layers so that it was possible to record the approximate depth at which each individual occurred. The greatest number, both of Insects and of other Invertebrates, occurred in the upper five inches of the soil.From the figures obtained in this investigation it appears that artificial manures have little or no effect on the soil fauna, while the effect of dung in increasing the numbers and the number of species of the fauna is very considerable.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07025.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.1A short account is given of the species of Humble Bees (Bombi) observed by the writer in North Wales and adjacent districts during the period 1919–27, with notes on their relative abundance and seasonal activities.2The chief economic plants visited by each species are Wed, together with brief mention of those cultivated and wild flowers most favoure

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07026.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.The structural evidence obtained from the study of the pits on the ninth abdominal segment ofAgriotes obscurusfavours the view that they are a pair of muscular impressions. The hairs lining the pit walls do not possess a nervous supply nor was any special nervous supply traceable to the pits as a whole. No structures which have been associated with sense reception in insects were found in the neighbourhood of the pits. There wm no evidence that the pits are a modified pair of spiracles as was suggested by one miter (6).With regard to the alimentary canal there are no salivary glands. The oesophagus possesses four ridges which project into its lumen and their muscular nature suggests that they are capable of independent movement.The mesenteron is devoid of gastric coeca and does not contain a peritrophic membrane of any type.The digestive fluid is secreted in vesicles which are budded off from the epithelial cells lining the midgut. The contents of the mesenteron has apH of between seven and eight which is similar to the reaction of its cell walls. The hindgut is a straight tube without clearly marked intestinal and rectal regions and there are no glands of any kind in this part of the gut.The malpighian tubes are four in number and are generally of a yellow colour, but it is not unusual to find blackened patches in the tubes which are due to dark masses of excretory matter blocking the tube.The dorsal vessel is non‐septate.Besides the supra‐ and sub‐oesophageal ganglia there axe 11 nerve massea in the central nerve chain—three thoracic and eight abdominal.The masses of fat body are characterised by their leaf‐like shape and gre

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07027.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

Summary.1Experiments concerning the degree of infestation ofThrips tabaciupon cotton plants under glasshouse conditions suggest that theinfestation factor, or number of thrip stages per 100 sq. cm. of foliage surface, varies inversely with the weight of water supplied.2Plants receiving excessive water supply have a lower infestation factor and a lower number of thrip stages per leaf as compared with plants receiving sufficiency of water supply; plants receiving insufficient water supply have a greater infestation factor than plants receiving sufficiency of water supply but have not necessarily a greater number of thrip stages per leaf; owing to their smaller foliage area however they suffer more from thrip attack.3Irrigation is more effective in influencing the degree of thrip infestation than is rainfall.4Irrigation on a flat soil surface is more effective than irrigation on a furrowed soil surface.5The effect of excessive water supply does not appear to be due to mechanical removal of thrips stages from the foliage, nor an injurious effect of soil moisture or atmospheric moisture upon thrips stages, nor alteration of the osmotic concentration of cell sap, although all three factors may operate slightly.6It is suggested that one factor concerned is the influence of heavy water supply upon the texture of certain soils, in promoting surface caking which will act inimically to soil pupating species of Thysanoptera.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1927.tb07028.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY