The Effects of Nitrogen,Phosphorus, Potassium Magnesium and Lime in Factorial Combination on Ripening Disorders of Glasshouse Tomatoes

The effects of nutrition on the incidence of fruit ripening disorders are described, based on studies of three varieties of tomato (Potentate, Moneymaker and J168) grown with 72 combinations of fertilizers in heated glasshouse borders. The treatments included three levels each of nitrogen and potassium in factorial combination with two levels of phosphorus, magnesium and lime.

Potassium sulphate markedly decreased the overall percentage of unevenly ripened fruit from all three varieties. Magnesium sulphate had a similar but smaller effect; the response to magnesium was greatest at low levels of potassium. The higher level of phosphorus increased the proportion of unevenly ripened fruit, the combination of low potassium and high phosphorus having a particularly adverse effect. The responses to nitrogen were complex and differed between varieties. Lime increased the proportion of unevenly coloured fruit from varieties Moneymaker and J168, significantly in the high nitrogen plots. Numerous other interactions between nutrients were found.

The effects of the treatments on specific forms of ripening disorder were recorded, including greenback, yellow and green blotch, and waxy fruit. Potassium decreased the incidence of all forms of ripening disorder. High phosphorus increased the proportion of blotchy and waxy fruit, but significantly decreased the incidence of greenback in variety Potentate.

Although the intermediate level of potassium in this trial (871 lb. K₂ 0 per acre) had previously been found sufficient for maximum yield, significant improvements in fruit quality were obtained at the highest level (1,742 lb. K₂O per acre).     

The Effects of Nitrogen,Phosphorus, Potassium,Magnesium and Lime in Factorial Combination on the Yields of Glasshouse Tomatoes

Tomato yields and soil analyses from a 3² × 2³ factorial nutritional trial are summarized for six seasons of cropping in heated glasshouse borders. The varieties were Potentate for four seasons, and J168 and Moneymaker (split plot) in the last two seasons. The soil was steamed before planting except in the first and third years.

Deficiencies of nitrogen and phosphorus decreased the yields in five out of six seasons, as also did potassium deficiency in four seasons. Significant positive interactions were found between these three nutrients. The highest level of nitrogen (680–830 lb. N per acre) was favourable when both phosphorus and potassium were at adequate levels in unlimed soil. No yield response was found to potassium in excess of the intermediate level (870 lb. K₂O per acre). The main effect of magnesium was not significant, but a positive phosphorus-magnesium interaction was found for variety Moneymaker.

Lime (carbonate) decreased the yield significantly each season. A significant interaction was found between lime and nitrogen level, the adverse effect of lime occurring at the high and intermediate levels of nitrogen. This effect of lime, and the lime-nitrogen interaction, may be due to induced boron deficiency.     

The Relation Between the Rate of Respiration of an Apple Fruit and its Content of Protein: I. The Value of this Relation Immediately After Picking

Tomato plants of two varieties (Potentate and Immuna) were grown for four seasons with different combinations of magnesium and potassium sulphate in heated glasshouses. Magnesium sulphate was applied either to the soil or as a foliar spray, with untreated plots as controls ; these treatments were combined factorially with two levels of soil potassium. The effects of the treatments on the magnesium and potassium contents of the soil, as extracted by 0 5N-acetic acid, are recorded.

Chlorosis of the leaves was widespread where magnesium was not applied. Foliar spraying effectively controlled the deficiency symptoms; treatment of the soil with magnesium sulphate was only partially successful in the first season but increasingly satisfactory thereafter.

In only one of the four seasons was there a significant increase in yield J due to the correction of magnesium deficiency. In that year (1959) the yields at the higher level of potassium were increased by 15%and 12%by the soil and spray treatments respectively (P=0·001).

The magnesium treatments slightly improved fruit quality as assessed by visual grading, mainly at the very low level of potassium in the last two seasons. The dominant factor affecting fruit quality was potassium, however, which markedly increased the proportion of uniformly coloured fruit and reduced the incidence of ripening disorders.

It is suggested that magnesium deficiency should be controlled by supplying this nutrient rather than by reducing the application of potassium salts below the quantity necessary for high fruit quality.

Variety Immuna gave higher yields and better quality fruit than Potentate throughout the trial.     

The Effects of Light Intensity,Day Temperature and Water Supply on the Fruit-Ripening Disorders and Yield of two Varieties of Tomato

A study was made of the effects on fruit-ripening disorders and crop yield of shaded and unshaded glasshouses maintained at both high and low daytime temperatures (80° F. (26 ? 5° C.) and 65° F. (18 ? 3° C.)), in which were grown two varieties of tomatoes (Potentate and Ware Cross) at two levels of watering.

Shading the glasshouses reduced the proportion of non-uniformly coloured fruit at the high temperature. At the low temperature, shading reduced the proportion in i960 but there was no effect in 1959. Light watering reduced the proportion of non-uniformly coloured fruit in the first year but it had little effect in the second year. The variety Ware Cross bore approximately 10% fewer non-uniformly coloured fruit than did Potentate in both years.

Shading the glasshouses reduced yield in both years, the decrease being greater (62%) in the very dull year of i960 than it was (40%) in the very sunny year of 1959. The house at the low day temperature yielded a 30% greater weight of crop than the warmer house. In both years the heavily watered plants yielded more than the lightly watered plants because of an increase in mean fruit size. Potentate and Ware Cross yielded similar weights of crop in both years but Ware Cross bore more fruits and had a smaller mean fruit size.

The gross cash return obtained in 1960 was reduced by shading the glasshouses, by maintaining a high day temperature and by growing the variety Potentate as opposed to Ware Cross. The differences in the watering regimes employed had little effect on the cash return obtained.

By assuming that yield and quality have simple mathematical relations with degree of shading, the profitability of shading is discussed. It is shown that shading is not likely to be profitable.     

Seed Number,Specific Gravity and External Appearance of Hollow Tomato Fruits

Experiments were carried out in Israel over several years with outdoor winter tomatoes, cv. Moneymaker. It was concluded that generally no correlation exists between the average number or weight of seeds per fruit and the frequency or grade of hollowness. The separation of regular, globe-shaped from irregularly shaped fruit substantially reduced the percentage of hollowness of the samples. The immersion of tomato fruits in tap or distilled water allowed satisfactory separation between hollow fruits, most of which floated on the surface, and normal fruits which mostly sank to the bottom.     

The Effects of Nitrogen,Potassium and Sub-Irrigation on the Yield,Quality and Composition of Single-Truss Tomatoes

The effects of nitrogen and potassium on the growth of single-truss tomatoes and on the yield and quality of the fruit have been examined. Two successive crops of cv. Minicraigella were grown with sub-irrigation in a tiered-trough system, the troughs containing a 7:3:2 mixture of loam, peat and grit. Four concentrations of nitrogen in solution (100, 150, 200 and 250 ppm N) were tested in factorial combination with three concentrations of potassium (200, 300 and 400 ppm K), the treatments being replicated four times.

Plant height and leaf length increased markedly with N concentration, as also did the numbers of flowers and marketable fruits per plant, the mean weight per fruit and the total yield. Low N levels delayed harvesting. The proportion of unevenly ripened fruit decreased with increasing concentrations both of N and K. The percentage of hollow fruits was decreased by high K but increased with N concentration.

The titratable acidity of the expressed fruit juices increased significantly with N concentration (P<0.001) but was little affected by K treatment. The N concentration of the nutrient solution also largely controlled the percentage of K in the leaves and the total uptake of this nutrient. These unexpected results were attributed to stimulation of growth by N, leading to increased water requirement and hence to increased application of both N and K by the automatic sub-irrigation system.

The highest yields and best quality fruit were obtained with 250 ppm N and 400 ppm K in the solution, although lower concentrations of K might be preferable after continued cropping in the same compost.     

A Supplementary Note on Fruit Spraying With A Glyoxalidine Preparation in 1948

An instrument is described for measuring the compression of tomatoes under a known weight. This has been used to study the effect of some of the many factors likely to influence the firmness of tomatoes. The measurements of compression were made along the axis from the calyx to the stylar scar.

The compressibility of the fruit increased threefold during ripening from the mature green to the fully red condition. The firmness of the fruits of two varieties increased with the number of locules per fruit.

Comparison of the fruits of eight varieties showed marked differences in firmness; the even-ripening form of Potentate (Potella) was the firmest variety tested, and Harbinger the softest. The compression readings were significantly and negatively correlated with the percentage of walls and placentae, and with the thickness of the fruit as measured along the axis of compression. Fruit size and the percentage of walls were themselves positively correlated.

Both lime and potash significantly increased the firmness of the fruit of variety Moneymaker. Phosphate had a slight beneficial effect, but no significant response was found to nitrogenous fertilizer.

Tomatoes of two varieties, grown with different combinations of shading, day temperature and watering, were examined. Fruits grown at a day temperature of 85° F. (29-5° C.) were 30% softer than those grown at 65° F. (18-3° C.). Some evidence was obtained that heavy watering softened the fruit, particularly under hot, shaded conditions.

Freshly-picked tomatoes of three varieties approaching the fully red condition continued to soften rapidly during storage (74° F.), the effect being highly significant even within three days.

The effect of fruit size on the compression readings, and on percentage compression, is discussed.     

The Influence of Vigour and Nitrogen Status on the Fruitfulness of Talisman Strawberry Plants

In a study on the growth and cropping of strawberries under contrasting soil nitrogen conditions in a trial extending over six years, annual split applications of Nitrochalk maintained distinct regimes of mineral nitrogen in the soil but 30 tons/acre F.Y.M., prior to planting, had little additional effect. Nitrogen deficiency was achieved by preplanting applications of straw but this only lasted for one season.

There was a regular pattern in leaf nitrogen concentration associated with the different phases of strawberry growth. The concentration showed a linear response to increments of fertilizer nitrogen. Leaf colour gave visual evidence of these differences.

F.Y.M. did not affect plant growth or cropping but nitrogen applications resulted in small increases in both plant spread and number of crowns per plant.

Nitrogen at 200 lb. N/acre depressed the yields of marketable fruit in each of the four years. This was due only in part to an increase in wastage and it is suggested that a high nitrogen status in the plant could reduce the number of fruits per truss. The lower rate (50 lb. N/acre) gave yields generally similar to the nil control.

Nitrogen levels had little influence on the intensity of flowering in spring, whereas autumn flowering decreased sharply as nitrogen levels increased. Floral initiation thus appears much more sensitive to the nitrogen status of the plant in July than in September.     

Influence of pre-planting applications of nitro-chalk,superphosphate, sheep manure and a fertilizer mixture,in factorial combination,on the growth of one-year-old peach trees

A field experiment was carried out with one-year-old peach trees to determine the influence of applications of nitro-chalk (N), superphosphate (P), sheep manure (SM), and a fertilizer mixture (X), in factorial combination, on tree growth during the first growing season. Fertilizers were mixed into the soil at planting sites about two weeks before tree planting.

Maximum tree growth was achieved when 3 lb. P and 36 lb. SM were applied per tree. However, all fertilizers depressed leaf bud development and early shoot growth and, in a few cases, application of 3 lb. N per tree resulted in tree death. It is concluded that heavy rates of these fertilizers should not be applied to planting sites prior to planting young peach trees. Rather, it appears from seasonal growth measurements that fertilizers should not be applied to newly planted trees until late spring (November).

The only consistent and significant interaction occurred between N and SM. Application of SM increased tree growth more in the absence of N than in its presence; i.e. the SM acted as a nitrogen source. SM depressed tree growth early in the growing season, probably because some of its components are readily soluble. However, later in the season it promoted growth and partly alleviated the detrimental effect on tree growth induced by 3 lb. N per tree. It is evident from calculated concentrations of elements per planting site that the SM treatment supplied larger quantities and a wider range of elements than the inorganic fertilizers.

In the absence of an N × SM interaction trees grew better if given nil or 1 lb. N than if they were given 3 lb. N. For some growth parameters, trees also grew significantly better if given 1 lb. N rather than nil.

Application of a fertilizer mixture containing potassium sulphate, magnesium carbonate, lime, ammonium molybdate, zinc sulphate, borax, Chel-138 iron chelate, and manganese sulphate to planting sites significantly depressed tree growth throughout the growing season, but this may have been due to molybdenum toxicity, although no visual symptoms were present.     

The Effects of Fruit Thinning on the Development of Cox’s Orange Pippin Apples in Relation to the Incidence of Storage Disorders

Severe hand thinning of fruitlets on Cox’s Orange Pippin trees five weeks after full blossom led to a doubling of fruit weight by harvest. Although the rate of cell division was stimulated slightly, the larger fruit size was due mainly to an increased rate of cell enlargement.

The respiration rate of whole fruits was slightly higher after thinning and the onset of the climacteric rise was advanced. Respiration per cell was correspondingly higher in the larger cells of the thinned fruit and respiration per unit protein was similar to that of fruit from unthinned trees.

Potassium, magnesium, and phosphorus contents, expressed on a fresh weight basis, were higher in the cortical tissue of the thinned fruits. Calcium per unit fresh weight was unaffected by thinning and the ratio of calcium to cell surface remained relatively constant throughout development in both types of fruit.

Senescent breakdown and bitter pit developed during storage only in the thinned fruit. Slight differences in the incidence of rotting and low temperature breakdown between the two types of fruit are attributed to the effects of maturity rather than of fruit size.     

The Effects of Tillage,Non-Tillage and Nitrogen on Yield and Fruit Composition of Citrus

Over the period 1947 to 1965 studies were made of the effects of four cultural treatments and four levels of ammonium sulphate on crop growth and fruit composition of Washington Navel and Late Valencia oranges, budded on to either Rough Lemon or Sweet Orange rootstocks. In terms of yield and quality, the best treatment combination was weed control by kerosene oil sprays together with 4 lb. of ammonium sulphate per tree per annum. For this treatment combination the average annual yield over the five-year period 1961–65 approached 500 lb. per tree.

Almost all the nitrogen requirements of mature citrus trees were obtained from clover grown during March to September and then rotavated into the soil. Repeated ammonium sulphate applications caused soil acidity, aggravating an inherent soil phosphorus deficiency. Basal superphosphate applications, made since 1955 at an average annual rate of 4 lb. per tree, gradually improved fruit quality.

From 1955 to 1965 small annual calcium carbonate applications of up to 30 lb. per tree were made to half the trial area. Although these applications only partially neutralized soil acidity there was a consistent tendency since 1961 for yield and fruit quality to be higher on limed plots. As there was no evidence of calcium deficiency, it is considered that liming treatments stimulated crop growth mainly by raising soil pH and increasing soil phosphorus availability.

Soil analytical results showed that considerable differences existed between the fertility status of inter-tree and under-branch-spread areas: base exchange capacities and soil pH were considerably higher under the leaf canopy than in inter-tree areas.

A study of fruit quality indices, summarized for four periods each of four years duration, suggests that the juice content of an orange is a more sensitive index of fruit quality than skin thickness or sugar and acid contents.     

Relations Between Growth of Leaves,Fruit and Shoot of Glasshouse Tomato Plants

The weekly rates of shoot extension and total growth in leaf length of the glasshouse tomato variety Potentate increased from germination until soon after the start of ovary swelling. It is postulated that when, or soon after, the first flower primordia were initiated, an internal reaction was stimulated that eventually resulted in the cessation of the progressive increase in the rates of shoot extension and growth in leaf length. Increase in the rate of vegetative growth ceased soon after the start of ovary swelling, but this occurred even when no ovaries were allowed to swell.

The diameter of the shoot was unaffected by removal of leaves but increased when no fruits were allowed to develop. Conversely, shoot extension growth was unaffected by removal of fruit but decreased when alternate immature leaves were removed, although the removal of mature leaves had no effect on shoot extension growth.

Removal of leaves was associated with a reduction in total fruit volume and an increase in total leaf length.

Removal of immature fruit was associated with an increase in total leaf length. Removal of alternate immature fruits had little effect on total fruit . volume ; the difference between normally fruiting plants and plants from which alternate fruits had been removed was less than 0?5%.     

The effect of rootstock on yield and quality of ‘Mutsu’ apples

Summary

Yield and fruit quality parameters were studied during three years in a rootstock trial with ‘Mutsu’ apple. M.9 provided the highest total yield per tree as well as the highest quantity of intermediate and yellow fruit as compared with J.9, M.26 and B.9. Within similar colour categories, significant differences among rootstocks were also recorded for fruit starch degradation pattern (SDP), firmness, titratable acidity (TA), and soluble solids concentrations (SSC). Generally, the lowest SDP and highest fruit firmness was found in fruits from trees on rootstocks M.26 and B.9. The highest TA was found in fruits from trees on rootstocks M.26 and J.9 and the highest SSC in fruits from trees on rootstocks J.9 and B.9. However, considerable variations among years were also recorded. Correlation coefficients between rootstock and several yield and quality parameters revealed high correlation to SSC for green fruit and TA for medium and yellow fruit and some correlation to yield and number of fruits per tree.     

Improvement of quality and storability of apple cv. Aroma by adjustment of some pre-harvest conditions

To improve the quality of the important Swedish apple cultivar Aroma and increase its resistance to bruising and storage decay, three studies were conducted at Kivik research station during the period 1998–2003. The effects of tree age, pruning time and nitrogen fertilization were investigated. Fruits from young trees (younger than 6 years) had a lower resistance to bruising and Pezicula malicorticis decay, while fruits from trees older than 20 years seemed to show a quality and storability decline. Choosing a suitable summer pruning time was an effective factor for fruit storage potential. Thinning cut during August (5–6 weeks before harvesting) improved fruit colour and decreased decay without negatively influencing tree yield. Applying fertigation according to fruit development phase and soil nitrogen content had a very important influence on fruit quality and storability. Appropriate nutrition supply produced more deeply coloured fruit that maintained their quality after storage for 4 months. The bruising sensitivity of cv. Aroma apples was correlated with their N and K/Ca content. More coloured fruits showed less sensitivity to bruising.     

The effect of nitrogen fertilization and shading on the incidence of “colour spots” in sweet pepper (Capsicum annuum) fruit

SUMMARY

“Colour spots” (CS) in pepper fruit is a physiological disorder characteristic of some sweet pepper cultivars. The symptoms are yellowish spots on the outer surface of affected fruits. We investigated the effects of shading and nitrogen supply on the susceptibility of three sweet pepper cvs (Maor, Lady Bell and 899) to CS. The most susceptible was ‘Maor’. The incidence of CS was promoted by high N and shading. The fruits of all cultivars had lower nitrogen concentrations than the leaves but there were no significant differences in fruit N content between Maor and the CS-insensitive cultivars. The CS-affected areas of the pericarp tissue had higher calcium concentrations than unaffected tissue. Differences in magnesium or potassium concentrations in these spots were less pronounced. Scanning electron microscopy revealed that the affected pericarp cells contained crystals, presumably of calcium oxalate. Only in ‘Maor’ fruits was the oxalate concentration elevated by approximately nine-fold when the nitrogen supply to shaded plants was increased. We suggest that in the fruits of the sensitive cultivar, oxalic acid production is enhanced under high-nitrogen + shading conditions and causes the CS damage, possibly be chelating intracellular calcium.     

Field control of strawberry fruit rot (Botrytis cinerea Fr.,) by fungicides (II)

Fungicide trials against strawberry fruit rot (Botrytis cinerea Fr.) were conducted in 1968, 1969 and 1970 on cv. Cambridge Favourite. Dichlofluanid was applied at 6 lb a.i./acre/year (6.72 kg/ha), tetrachloroisophthalonitrile at 7.5 lb a.i./acre/ year (8.41 kg/ha) and benomyl at 1.5 lb a.i./acre/year (1.68 kg/ha). The first spray was applied when two or three flowers per plant had opened, and one, two or three subsequent applications were made at approximately 10-day intervals. Three or four applications gave better control than two.

Application of any of the three fungicides reduced fruit rot and resulted in improved yield. Benomyl and tetrachloroisophthalonitrile caused malformation of fewer fruits than dichlofluanid.     

Effects of pollen-load on fruit yield,seed production and germination in melons,cucumbers and squash

Summary

Four cultivars of each of three cucurbit species were used to examine the effects of pollen-load (i.e., the number of pollen grains deposited on the stigma of pistillate flowers) on fruit-set, seed-set, and germinability (i.e., germination percentage and germination rate) in four greenhouse experiments. Increasing pollen-load increased the number of fruit per plant in the four melon cultivars over two growing seasons, and in two non-parthenocarpic cucumbers, but had no effect on all four squash cultivars. In most cases, increasing pollen-load increased the number of fully-developed seeds, decreased the percentage of empty seeds, and tended to decrease mean seed weights. On average, melons produced 2.2 fruits per plant in the Winter, and only 0.9 fruits per plant in the Autumn. In contrast, melons produced 275 fully-developed seeds per fruit in the Autumn, but only 57 seeds in the Winter. Mean melon seed weight was higher in Autumn, and the sum of all seed yield component effects resulted a significantly higher seed yield per plant in the Autumn. Germinability of melon seeds from the Autumn season, and of squash seeds from the Winter season, were not significantly affected by pollen-load treatment. These data are contrary to the theory that microgametophyte competition has a positive effect on the vigour of the progeny. The lower germinability of melon seeds obtained by passive pollination (i.e., self-pollination in covered flowers) may be due to the fact that pollination without insect or human interference yielded only a few seeds per fruit, and, under such circumstances, there may be a survival advantage for slow and distributed germination.     

The relationship between different spray combinations of certain fungicides with calcium nitrate and the incidence of bitter pit and fungal diseases of apple

Two apple cultivars, Cox’s Orange Pippin and Worcester Pearmain, were sprayed at high volume for scab control in two seasons with either captan or thiram, with dinocap to control mildew. On Worcester, it was confirmed that thiram reduced crop and increased fruit russet and bitter pit incidence; the proportion of misshapen fruits was also increased. On Cox, thiram reduced crop number, without any compensatory increase in weight, and provided inferior scab control as well as increasing fruit russet.

The application of commercial calcium nitrate (C.C.N.) four times between mid-June and mid-August led to a considerable reduction in the incidence of bitter pit and storage rots in fruits from trees sprayed with captan and dinocap; it also partially offset the greater incidence of bitter pit associated with thiram treatments. In contrast to this, the application of a similar total amount of calcium, either in the form of a standard lime sulphur programme or by adding C.C.N, to the organic fungicide programmes for scab control, i.e. from April to mid-July, failed to reduce the incidence of bitter pit on either cultivar. Neither C.C.N, programme affected cropping, fruit russeting or scab control on either cultivar.

The ratio of potassium to calcium was higher in leaves and fruits from Worcester trees receiving thiram than in those from trees receiving captan; the application of C.C.N, in the summer reduced this ratio in fruits from trees receiving captan but not in those from trees receiving thiram, although it reduced the incidence of bitter pit associated with both fungicide programmes.

Results on Cox show that fungicide deposition and control of scab were independent of fungicide formulation and of the presence or absence of C.C.N. ; mildew control was not affected when C.C.N, was applied as the recommended summer programme.     

Light distribution in apple orchard systems in relation to production and fruit quality

Summary

The effect of tree density (2000, 2667, and 4000 trees per ha) and the ratio of between to within-row distance (1:1, 2:1, and 3:1) on light interception, fruit production, colour and individual fruit weight was evaluated in a ten-year comparative field study with apple at two sites in The Netherlands (51° 30′ and 52°0′ N) and one site in Denmark (55°30′). For each combination of tree density and rectangularity, trees were pruned at three heights (1.50, 1.88, or 2.25 m). Fruit production over nine years and seasonal incoming radiation between bloom and harvest were 20 and 15% greater in The Netherlands. Climate-based estimates of potential production as provided by a crop-growth model, predicted 18% higher fruit production in The Netherlands. Production was proportional to light interception and increased with tree density, but the amount of well-coloured fruit per ha in later years did not increase with planting density. With more than 70% light interception in later years, a large proportion of shade within the canopy was found. Fruits were smaller and less coloured at the Danish site. Fruits were more coloured in the taller and more open trees, even at the highest tree densities. Plantings with 1:1 and 2:1 between-to within-row distances intercepted more light and had a more uniform light distribution than 3:1 designs. This led to higher fruit production and better fruit colour. Fruit weight was not influenced by tree density, rectangularity, or tree height.     

Inter-Relations of Hesperidin,Some other Natural Components and Certain Enzyme Systems in Developing Shamouti Orange Fruits

The relationships of a large number of components and enzyme systems of the Shamouti orange fruit have been studied during the growth period extending from April to December. Data have been evaluated with the help of an electronic computer.

Early in July, towards the end of the first period of growth, peel thickness attains its maximum, cell divisions almost cease, growth of internal fruit parts (endocarp) begins and many fruit components (as ascorbic and dehydroascorbic acids and the bioflavanoid hesperidin) and many enzymic systems (as peroxidase, catalase, indole acetic acid oxidase and ascorbic acid oxidase) attain their maximum values and activities when expressed on a total nitrogen basis. This points to higher metabolic activity of tissues during the first period of growth.

During the second period (July to December) concentrations and activities of components decrease, relative to fresh and dry weight and to total nitrogen, partly because of dilution by inert cellular components and partly through decreasing metabolic activity. Only by expressing results on a per fruit basis (because of the large increase in volume of individual fruits) do the values of some components, especially reducing sugars and catalase activity, continue to increase.

The ascorbic acid system, hesperidin, and enzymes effective in oxidation of ascorbic acid, in degradation of the growth hormone indole-3-acetic acid and otherwise active in oxido-reduction reactions are interrelated' both when the curves are compared and after the time effect has been removed. This suggests that these systems are interrelated irrespective of the age of the fruit.