The amount of calcium in mature apples appears to be related to certain storage disorders. For Cox's Orange Pippin a difference of 2 mg in a total calcium content per fruit of about 5 mg can make the difference between good and bad keeping. Most of the calcium moves into the fruit during the first few weeks of its development (approximating to the period during which the cell walls are being formed). Thereafter (during the period of cell expansion) the movement of calcium is no longer in one direction only, and as much as 1 mg may move out of the fruit. This may be of the same order of magnitude as that contributed by calcium sprays, which are now commonly applied to improve storage quality. The factors affecting the movement of calcium into or out of apples are not known, but the limited evidence available suggests that movement of calcium out of the fruit may occur during periods of abnormally dry weather. These are the conditions which are usually associated with the occurrence of bitter pit.

Previous results are confirmed. There are high concentrations of minerals in the outer 0.5 mm., a fall to minimum values in the outer cortex, and then again higher values in the core region of apples. Relative to the rest of the tissue, magnesium, calcium and nitrogen are in very high concentration in the peel.If the peel is excluded, alcohol-soluble matter (which is mainly sugar) and starch are the only fractions which showed a steady decrease in concentration from outside to inside.There were no obvious differences in the distribution patterns between two samples of apples with different keeping qualities.Apart from a considerable loss of free acid from the peel, there were no great changes in concentration patterns after storage for about 10 weeks at 0".It is concluded that there will be inaccuracies if i t is assumed that analysis of portions of tissue will give the same results as analysis of the whole fruit. IntroductionIt has previously been shown1 that concentrations of potassium, phosphorus, magnesium and calcium are higher in the tissue near the centre of an apple than in the outer cortex. It is also known that the concentrations of these elements are usually higher in the peel than in the pulp.a Hence there must be a region in the outer cortex where the concentrations of these elements are at a minimum. Ulrich3 has summarised much of the previous work on physical, chemical and physiological gradients in fruit in general. There is, however, very little information on gradients in apples, and improvements in methods now make it possible to deal with smaller sections of fruit.The analyses described below were designed to investigate the pattern of concentrations within the apple to finer limits than had previously been attempted, and in particular to investigate the regions close to the peel. The work was also extended to include analyses of other components of the apple, such as acid, starch and pectin.

and Ultrasorb S.C. 120!240. (To decolorise the extracts, the weight of charcoal needed is about ten times that of the plant material extracted.)The following solutions are then percolated through the column at the rate of about I ml. pcr rnin. : (i) The plant extract containing Fe-EDTA, washed through with IOO ml. of water ; (ii) IOO ml. of 5% ethanol ; (iii) 250 ml. of 25:& ethanol (this elutes the Fe-EDTh in high yield but not always quantitatively). [The column eluates arc colourless exccpt a t stage (iii) where traces of plant colouring matter also appear.! The eluate from stage (iii) is evaporated down and spatted on to the paper chromatograms. Pa$er chroinatographyAfter development with the phenol-water system as described above, iron chelates show as dark spots on the dried chromatogram in ultra-violet light. The paper is then stained b y the following procedure : (i) dip in h'iS0, solution, 0.01';; in methanol ; (ii) remove most of the solvent in a cool air stream and then expose the papcr to NH, vapour ; (iii) dip in dimethylglyoxime solution, 0.1:; in ethanol. The chelating agents then S~O M . as white spots on a pink background. Acknowledgment rock, Grays, Esses. The activated carbon used \vas the gift of the Rritiah Carbo-Sorit LTnion Ltd., \Vest Thur-The Rcscarch Station Long Asliton Rristol Rvccived IS January, t$w ; aiiirndd manuscript 2 5 May, IOGO

During the development of apples the most striking difference in mineral uptake is that between the potassium and calcium patterns. Potassium uptake continues throughout growth, being an essential constituent of the buffer system in the vacuole. Calcium uptake falls off appreciably after the initial period of cell division. It is suggested that the initial supply or availability of calcium in the tree may be of importance in determining the later development of physiological disorders. The mineral content of apples is not appreciably affected by normal variations in date of picking, although there may be small changes. The most obvious drift is a consistent late uptake of sodium.

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