Investigations on Chlorosis of Fruit Trees.: II.—The Composition of Leaves,Bark and Wood of Current Season’s Shoots in Cases of Lime-Induced Chlorosis.

Summary

Radish (Raphanus sativus) is an important crucifer vegetative crop in Japan. We studied the morphological and anatomical characteristics of radish roots over a 6-week period using three radish cultivars with three different root shapes: long-type (Lt), round-type (Rt), and thin-type (Tt). We found that significant differences in the thickness of the roots first appeared 4 weeks after sowing. In Lt and Rt plants, the roots thickened rapidly, especially in the middle section that is composed of the lower part of the hypocotyl and the upper part of the taproot. The taproot increased in length in Lt plants, but failed to elongate in Rt plants. In Tt plants, the roots showed much smaller increases in mean diameter and length. Transverse sections through the taproots showed significant differences, both in cell number and in cell size 4 weeks after sowing. Lt and Rt plants contained more cells in the secondary xylem and phloem than Tt plants, and cell expansion was also greater in the storage roots of the Lt and Rt cultivars. These results will contribute to a better understanding of the development of radish roots of different shape.     

Root Pruning—A Poorly Understood Management Practice in Fruit Trees

ABSTRACT

Root pruning (RP) is a management practice intended to reduce excessive shoot growth resulting from a disturbed root/shoot-balance. It appears to function by limiting the gibberellin activity in fruit trees by interfering with endogenous growth control. In this way, not only shoot growth but also fruit development and flower-bud formation can be influenced by one common mechanism. The results are contradictory and often unpredictable. The prospects of RP as a management practice are rather limited.     

Long-Term Influence of Irrigation Systems on Postharvest Fruit Quality Attributes in Mature ‘Autumn Rose Fuji’ Apple Trees

ABSTRACT

In a long-term study between 2008 and 2011, effects of various evapotranspiration-based (ETc) irrigation systems on yield and fruit quality attributes of fully matured ‘Autumn Rose Fuji’ apple trees (Malus × domestica Borkh) after 5 months of regular atmosphere storage were examined. Trees with a full sprinkler (FS) system received about 39% more water than those with a full drip (FD) system over the period of 2008–2011. Fruits from trees with FS and FD were larger, while those with 50%FS were smaller than those from all other irrigation treatments. Averaging values over 4 years revealed that applications of any form of deficit irrigation, either by microjet irrigation or by drip, increased fruit-soluble solid concentration and firmness but decreased water core after storage. Trees receiving FS and FD systems (full irrigation systems) had lower fruit firmness reduction after storage than the treatments receiving deficit irrigation systems. Considering yield, and quality attributes in this study, a well-calculated ETc-based FD irrigation system is recommended over any other irrigation regime.     

Effects of Fertigation on Pigment Pattern and Fruit Quality of cv. ‘Gala’ Apples

Fruit pigmentation in ripening cv. ‘Gala, Schniga’ apples was monitored under the influence of fertigation weekly during 21 July–31 August 2009, i.e. 34 days before and 7 days after the optimal harvest date in Slovenia. The soil was a heavy loam clay with high humus content (2.8 %) and high acidity (low pH 4.9). The spectral indices NDVI (Normalized Difference Vegetation Index) and NAI (Normalized Anthocyanin Index) were obtained by a PA 1101 on attached fruit on the transition between the ground and blush colour of the fruit surface. NAI increased slowly from 0.25 to 0.6 two weeks prior to optimum maturity. NDVI values fell from 0.9 to 0.2 before and during ripening, with significant changes starting ca. 3 weeks before and during the week after the optimum harvest date. Fertigation delayed fruit ripening viz harvest date by ca. 4 days. Fertigation delayed changes in the intensity of the fruit’s epidermal pigments, expressed as NDVI for 1 week and NAI for 4 weeks, respectively, but had no significant effect on fruit colour or NDVI and NAI values at the optimal harvest date. At this time, those fruits from the fertigated trees were firmer with a lower starch index compared with the un-fertigated control. Statistically, highly significant correlations were found (p?≤?0.01) (r?=?0.35 to r?=?0.91, R²?=?0.11–0.83) between all the studied spectral and standard parameters i.e. fruit fresh firmness, soluble solids content and starch index.     

Influence of Melatonin Treatments on Fruit Quality and Storage Life of Sweet Cherry cv. ‘Sweetheart’

The study was carried out to determine the effect of melatonin on quality and postharvest life of sweet cherries (Prunus avium L.) cv. ‘Sweetheart’ during storage. The fruits were dipped at different concentrations of melatonin (0, 250, 500 and 1000?µmol l^?1 for 10?min) and distilled water as control. The changes of sweet cherries were assessed at 7?day intervals by evaluating the following quality parameters: firmness, soluble solids content, titratable acidity, respiration rate, color values (L* and chroma), ascorbic acid content, total anthocyanin content, total phenolic content, and antioxidant activity. The results showed that increasing the dose to 1000?µmol l^?1 melatonin had a remarkable effect on maintaining the quality of sweet cherry. 1000?µmol l^?1 and 500?µmol l^?1 melatonin treatments significantly inhibited the decrease in firmness, ascorbic acid, total phenols, total anthocyanin, antioxidant content and reduced color changes and respiration rate. However, the total soluble solids content and titratable acidity of the fruit were not influenced by melatonin applications. These findings indicate that melatonin treatment may be effective in maintaining quality and bioactive compounds of sweet cherry fruit.

     

Studies in Biennial Bearing: III. Growth Studies in ‘ON’ and ‘Off’ Year Trees

Plum crops in the UK are often uneconomically low because of unfavourable weather at blossom time leading to low fruit set. In view of the promising results obtained with fruiting hormones on other crops, the effects were investigated of mixtures of gibberellic acid, NN’-diphenylurea and 2-naphthoxyacetic acid applied to Victoria plum during the two months following full bloom. Large increases in set and subsequent yield were obtained with two applications. Treatment at 50% petal fall was detrimental to set, whereas treatment four weeks later was essential for improved set. Flowering in the year after hormone treatment was inhibited, the reduction being attributable to the increased crop load and to the use of gibberellin per se. The results are compared with those described by other workers using different cultivars, and the practical implications of hormone spraying discussed.     

Evidence of Clonal Variation and Latent Virus Effect on the Vigour of Cox’s Orange Pippin Apple Trees on M.9 Rootstocks

Apple trees on M.9 EMLA rootstocks free from known virus are at least 50% larger than those on M.9a containing latent virus. Evidence is presented that about half of this difference can be attributed to clonal variation and the rest to virus effects.     

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.     

Tree Fruit Growing—Research and Production in Germany: A Statistical and Bibliometric Analysis of the Period 1950–2010

Germany is one of the leading European countries in tree fruit growing and the fruit produced has an actual production value of 794?million?€. Six decades, from 1950 to 2010, of fruit production and internationally relevant scientific output for fruit crops—apple, pear, cherry, plum, apricot, and peach—were analysed in this study. Bibliographic and bibliometric analyses were based on the Science Citation Index^?. Data were compared and discussed in the European and global context. The German annual per capita consumption of fruit amounts to 125.5?kg/a originating from commercial intensive fruit growing, including 71.8?kg/a of fresh fruit, 48.3?kg/a of citrus and tropical fruit, 3.8?kg/a nut fruit, and 1.6?kg/a dry fruit. Approximately 25?kg per annum and inhabitant has to be added to the total fruit consumption, since a conspicuous amount of fruit originates from meadow orchards and house gardens. Nevertheless, Germany’s self-supply with fruit is a low 22.4%. Within the EU (2009/2010), Germany ranks fourth in apple production, tenth in pear production, fifth in cherry production, sixth in plum production, and 15th in the production of apricots and peaches. Based on the number of international scientific articles published in Germany, fruit crops can be ranked in descending order: apples, cherries, pears, plums, peaches and apricots. Relating the scientific output over the last six decades to the production data of the same country nowadays achieved, we obtain an indicator for the scientific impact on the crop production. On a worldwide comparison Germany ranks tenth for apple, sixth for pears, 21st for cherries, 17th for plums and first for apricots and peaches. With regard to the absolute output of scientific original articles Germany ranks fourth worldwide for apples, eighth for pears, second for cherries, fifth for plums, ninth for apricots and 14th for peaches, indicating that research on tree fruit growing in Germany supports the economic competitiveness of its production regions with highly specialized knowledge.     

The Effect of Conditions of Storage on the Respiration of Apples: III. The Effect of Modulation of Temperature on the Respiration of Cox’s Orange Pippin Apples,and on the Extent of Low Temperature Injury

When apples which develop low temperature breakdown (LTB) at 32° F. are moved from 32° F. to 65° F. for 3 to 5 days at about the 7th to 8th week of storage, they subsequently develop within a given period of storage less LTB than apples kept at 32° F. continuously.

The respiration of apples susceptible to LTB increases steadily during storage at 32° F. If these apples are warmed to 65° F. during the period of exposure to 32° F., the subsequent rate of respiration at 32° F. is lower than before warming, and continues at a lower rate than for apples kept at 32° F. continuously.

If the apples are moved to 38° F., without an intermediate treatment at 65° F., the rate of respiration is higher than for apples at 38° F. continuously, and this higher rate persists.

If there is an intermediate wanning period at 65° F., the respiration of apples moved from 32° to 38° F. is of the same order as that for apples kept at 38° F. continuously.

The respiratory quotient of apples at 32° F. or at 38° F., which is indicative of the type of respiratory activity, is typical for the temperature at which it is measured, and is not affected by the warming treatment. The effects of wanning on both the incidence of LTB and respiration are similar for apples stored in air and in 2% oxygen: 98% nitrogen.     

Interaction of Crop Load and Irrigation on Yield,Fruit Size,Color and Stem-end Splitting Ratio of Apple c.v. ‘Gala,Galaxy’

In this study, the interaction between crop load and irrigation level on yield, fruit size, skin color and stem-end splitting fruit ratio in the apple cultivar ‘Gala, Galaxy’ grafted on rootstock M9 were investigated. Six irrigation programs were applied during the whole growth season: deficit irrigation (rates of 0.25 kc, 0.50 kc, 0.75 kc), full irrigation (rate of 1.00 kc), excess irrigation (rate of 1.25 kc) and non-irrigation (rates of 0.00 kc of “Class A” pan evaporation coefficient). Four crop loads in each irrigation application were performed by hand thinning after the June drop as a- a low crop load (3 fruits cm^?2 TCA), b- a medium crop load (5 fruits cm^?2 TCA), c- a heavy crop load (7 fruits cm^?2 TCA), and d- an un-thinned crop load (>?7 fruits cm^?2 TCA). The total tree yield increased with crop load and irrigation levels. Fruit size was significantly increased by the low crop load. Irrigation increased the fruit size compared to non-irrigation treatment. Further 0.75 kc, 1.00 kc and 1.25 kc irrigation treatments significantly increased the fruit length. Irrigation reduced the fruit flesh firmness. While the low crop load increased the skin red color, it decreased the fruit skin brightness. The yellowness of skin decreased with increasing in the irrigation amount. Irrigation reduced the skin brightness and yellowness, but it increased red color. Crop load and irrigation significantly affected the stem-end splitting fruit ratio. While the splitting fruit ratio increased with a decrease in the crop load, it decreased with an increase in irrigation amount, relatively. Consequently, the low and medium crop load treatments would be beneficial to increase the ratio of marketable fruits without any significant losses in yield for ‘Gala’ apple, especially under 0.75 kc deficit irrigation treatment.     

The Minimization of Variability in Experiments on Apples Planted on the Site of A Previous Orchard: I. The Effect of Cultural Treatments Associated with Three Years’ Arable Cropping

Most of the frequency distributions of onion bulb weight throughout the growing period were found to be significantly and positively skewed. The positive skewness was significantly greater at high density than at low and increased significantly with time from sowing. A nomogram relating yield of various onion grade sizes to plant density was derived. For a particular cultivar grown in a known environment such a nomogram enables the plant density for optimum yield of a specified grade to be predicted.     

Studies on the hawthorn (Crataegus azarolus L.): III. A potential rootstock for ‘Golden Delicious9 apple and ‘Williams’ pear

Seedlings of the hawthorn Crataegus azarolus L. were budded with ‘Williams’ pear and ‘Golden Delicious’ apple and followed for compatibility, growth control, precocity and suckering. Four years of observations indicated that the hawthorn is compatible with ‘Williams’ and ‘Golden Delicious’, conferring growth control and precocity; and producing suckers profusely. On the other hand, bud break in ‘Williams’ started 10 d earlier and gave longer shoots than ‘Golden Delicious’. Delayed symptoms of incompatibility and long-term reciprocal influences require further study.     

Biotic homogenization of China’s urban greening: A meta-analysis on woody species

Human preferences for the species in urban greening have greatly facilitated the spread of non-native species, resulting in the homogenization of urban plant communities across spatial scales. We selected 11 major cities along the Yangtze River in China and examined the species composition in their urban plant communities. We found that China’s urban plant communities are becoming homogenized, as urban communities of different cities are highly similar to each other despite the geographical separation. Meanwhile, these artificial communities we investigated have diverged greatly from the natural communities at both the city and the geographic scale. We recorded a total of 91 woody species that have been used in urban greening in all 11 cities. Of those species, 27% were cultivars and introduced species, and 25% were being used outside of their native distribution ranges in China. This may be explained by the market and urban planners who tend to favor greening plants that are highly profitable and have aesthetic ornamental traits, rather than spending time introducing and acclimatizing the native species in each city. Given the current trend of homogenization, measures that recognize the importance of native species should be emphasized with comprehensive urban planning strategies.     

Effect of intermittent as compared to continuous CO2 enrichment on growth and flowering of Chrysanthemum × morifolium Ramat. and Saintpaulia ionantha H. Wendl

Plants of three cultivars of Saintpaulia ionantha and Chrysanthemum × morifolium were grown until flowering at 335 (normal) or 900 μl l⁻¹ CO₂ (high). Continuous high CO₂ concentration increased the final dry weights from 76 to 123% in Saintpaulia and from 15 to 32% in Chrysanthemum compared to the normal concentration. Changing the CO₂ concentration from normal to high (intermittent) in intervals of 1 h resulted in dry weights intermediate to that of constant normal or constant high CO₂ concentrations in both species. Morning and evening enrichment gave the same effect as 1-h intermittent enrichment in Saintpaulia. High CO₂ concentration given every other day gave the same effect as 1 h intermittent CO₂ in Chrysanthemum. Increased dry weights were accompanied by more and larger leaves in Saintpaulia, and mainly by thicker and longer stem and more lateral breaks in Chrysanthemum.Time to flowering was significantly reduced by CO₂ enrichment in Saintpaulia, but was generally not affected in Chrysanthemum. Number of flowers and flowerbuds was increased by CO₂ application in both species. Constant high CO₂ concentration generally had effects superior to that of the intermittent treatments.     

Two faces to the greenery on housing estates–mitigating climate but aggravating allergy. A Warsaw case study

Interest in the climate and an awareness of the beneficial cooling influence exerted on it by biologically-vital areas is growing, as climate change progresses, hot weather is more frequent as well as the urban heat island more intense. It is necessary to protect existing greenery in the cities and to introduce new planting. However plants in a warmer climate can produce larger amounts of pollen and are more readily able to initiate an allergic reaction among those prone to them. That means—not every greenery is advantageous for humans in the cities. In the research two housing estates built at different times and differ in type, density and age of buildings, as well as in the composition and the percentage of biologically vital area and the species planted were examined. Detailed inventory of tall greenery entailed the trees and shrubs and next their assumed allergenic potential was made. Cooling effect likely is derived from the difference in greenery, but the other factors such as differences in the density of buildings and spatial organization of the estate could also influence it. The older estate with the ratio of biologically vital areas of 54.3% is characterised by more favourable local climate than the newer estate, with the ratio of biologically vital areas equals 40.7% and young vegetation. On the newer one the perceptible thermal conditions did not differ significantly compared with the city centre. Unfortunately, on Koło Estate trees creating mild thermal conditions are also the trees promoting allergies most severely: birches, poplars and limes. And they are planted usually around playgrounds and kindergarten. The trees of high allergenicity should be partially removed, even risking small worsening thermal conditions.     

Effect of inter-specific rootstocks on inorganic nutrient concentrations and fruit quality of ‘Hort16A’ kiwifruit (Actinidia chinensis Planch. var. chinensis)

Summary

Inorganic nutrient concentrations in leaves, xylem sap and fruit from ‘Hort16A’ kiwifruit (Actinidia chinensis Planch. var. chinensis) vines grafted onto eight inter-specific rootstocks [A. deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa; A. eriantha Benth.; A. hemsleyana×eriantha; A. macrosperma C.F. Liang; A. chrysantha Merr.; A. kolomikta (Maxim. et Rupr.) Maxim.; A. kolomikta (Maxim. et Rupr.) Maxim.; and A. polygama (Sieb. et Zucc.) Maxim.] were measured over three seasons. The nutrients analysed were phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn) and boron (B). The objectives of these studies were to identify rootstocks which induced relatively high or low levels of nutrients in the scion cultivar, and to correlate the nutrient concentrations of the fruits with the incidence of storage disorders. The use of inter-specific clonal rootstocks had a substantial effect on the accumulation and concentration of inorganic nutrients in the fruit, leaves and stem sap of ‘Hort16A’ kiwifruit vines, but few consistent relationships were observed between fruit nutrient concentrations and the incidence of storage disorders. Vines on A. hemsleyana×eriantha accumulated high levels of P in their fruits, leaves and xylem sap, and high levels of Ca and Mg in their leaves and xylem sap. Vines on A. macrosperma accumulated high levels of K in their fruits and leaves. In general, vines on rootstocks with low vigour (i.e. A. polygama; A. kolomikta) accumulated relatively low levels of nutrients. The incidence of physiological pitting, a mineral-related storage disorder, was higher in fruit with lower Mg concentrations. While rootstock-induced differences in the vigour of vines had an important role in determining nutrient concentrations in fruits and leaves, some rootstocks clearly had a stronger inherent ability to absorb nutrients from the soil than others, independent of their effect on vine vigour.     

Potassium Mineral Nutrition Combined with Sustained Deficit Irrigation to Improve Yield and Quality of a Late Season Peach Cultivar (Prunus persica L. cv ‘Chatos’)

ABSTRACT

Fruit quality traits are directly related to agronomic practices such as irrigation and fertilization, especially potassium supply since its effects on quality and water drought resistance. The objective of this study was to evaluate the effect of different combinations of potassium rate and application mode (in soil: 200S and 100S, foliar spray: 100F) with two irrigation regimes (FI: irrigation with 100%ETc and DI: irrigation with 66%ETc) on peach yield and quality parameters. The experiment was performed during two consecutive years. At harvest, only in the second year significant differences between treatments were observed in yield. In fact, potassium foliar spray, even in DI regime, improved yield. The fruit diameter was slightly affected by treatments in the first year. However, in the following season foliar potassium spray even in DI water regime increased fruit size. Concerning the firmness, no significant differences were observed in the first year except for the second year it decreased with DI strategy independently of potassium treatment. The soluble solids content was strongly affected by the treatments. The highest values were observed in 100F+DI treatment with no significant effect on acidity. Vegetative growth was affected only by water regime which DI reduced shoot length.