Studies on the relationship between leaf number and area and fruit development in mango (Mangifera indica L.)

The optimum leaf number: fruit ratio in various mango cuitivars was sought by isolating individual fruits with known numbers of supporting leaves by shoot girdling. ¹⁴CO₂ feeding experiments showed a higher rate of carbon fixation in the leaves of girdled shoots than of control shoots but the translocation of ¹⁴C assimilates to the developing fruits on the girdled and control shoots was comparable. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable to that of leaves on control shoots. In all the cuitivars studied it was observed that 30 leaves, the maximum available on a shoot, could not support the growth of a single fruit to normal size. The results also show that fruit development depends not only on the current assimilates but also to a great extent on reserves. The utilization of reserve metabolites from vegetative organs during the ‘on’ year could be a contributing factor towards biennial and erratic bearing.     

The Influence of Shoot Competition on Fruit Retention and Cropping of Apple Trees

Fruit set was increased by removing all shoots 5 days after full bloom and at weekly intervals thereafter from trees of Sunset and Laxton’s Fortune, but removing shoots from Fortune trees 25 days after full bloom produced no beneficial effect on fruit retention. All treatments resulted in a heavier rate of fruit shedding during the ‘June drop’ period than occurred from control trees, and at harvest the trees without shoots had fewer fruits, and lower yields, than the controls. In a comparison of shoot removal and shoot tip removal starting 15 days after full bloom on Fortune trees, both treatments improved set, but whereas shoot removal caused a heavier ‘June drop’ compared with untreated trees, shoot tip removal increased the number of fruits retained to harvest and produced a yield increase. The difference between the two treatments in their influence on fruit retention, during and after the ‘June drop’, is accounted for by the beneficial effect of a relatively small number of leaves on each tipped shoot. Studies on the pattern of distribution of photosynthates, using ¹⁴CO₂ and autoradiography, produced results supporting the concept of competition between fruits and shoots and also showed changes in the pattern of assimilate movement brought about by shoot tip removal. It is concluded that competition between fruits and shoots, occurring during blossoming and the following 2–3 weeks, may limit fruit set, but the presence of shoot leaves is beneficial to fruit retention in the later part of the season, particularly during the ‘June drop’ period.     

螺旋环剥对‘糯米糍’荔枝坐果与碳水化合物及激素的影响

研究结果表明,幼‘糯米滋’荔枝主要螺旋环剥能减少碳水化合物向根系转运,从而增加叶片和果实中的碳水化合物含量,增多果实中赤霉素类物质和降低脱落酸类物质含量。坐果率的提高与赤霉素／脱落酸的比值较高关系密切。     

Subject Index

Prohexadione-calcium (ProCa) is a gibberellin biosynthesis inhibitor with limited persistence and low toxicity that has recently been registered as a shoot growth retardant for apples in North America (Apogee^®) and Europe (Regalis^®). We investigated the response of six different pear cultivars (‘Rosemarie’, ‘Forelle’, ‘Packham's Triumph’, ‘Flamingo’, ‘Early Bon Chretien’ and ‘Golden Russet Bosc’) to ProCa in the Western Cape, South Africa, over the period 1999–2003. ProCa treatments ranging from 50 to 250 mg l⁻¹ were applied between one and three times per season and were compared with girdling and control treatments. ProCa application reduced shoot growth in all of the cultivars. ‘Forelle’, was least responsive and showed a reduction in 2002/2003 but not 2001/2002. ‘Rosemarie’, ‘Flamingo’, ‘Packham's Triumph’ and ‘Golden Russet Bosc’ were most responsive, with shoot growth being reduced by up to 50% of the control for the latter two cultivars. The response to number of applications and ProCa concentration was not consistent across cultivars. ‘Early Bon Chretien’, for example, only responded to high ProCa concentration, whereas ‘Rosemarie’ was very responsive at the lowest ProCa concentration. ProCa application improved fruit set but decreased final fruit size in some of the cultivars, particularly in ‘Rosemarie’. It also caused a decrease in return bloom in ‘Forelle’ and ‘Packham's Triumph’. The response of different cultivars to girdling, in terms of shoot growth and fruit set was highly variable. Girdling tended to increase final fruit size and return bloom. ProCa shows potential as a shoot growth retardant for the pear cultivars investigated, but the response of reduced fruit size in some cultivars requires mitigation. Future research on combined girdling and ProCa treatments may be instructive.     

螺旋环剥对幼龄‘桂味’荔枝果期光合和蒸腾作用的影响

以6年生幼龄‘桂味’荔枝(Litchi chinensis Sonn.‘Guiwei’)为试材,于5月果实发育期,从螺旋环剥处理和对照树上分别选取来自同一基枝的有果枝和无果枝,观察枝梢生长的情况并进行叶片光合和蒸腾作用的研究。结果表明:螺旋环剥有利坐果;螺旋环剥缩小有果叶与无果叶在光合效率上的差别,显著降低了叶片的最大光合速率(Amax)、表观量子效率(AQY)和羧化效率(CE),提高了光补偿点(LCP),削弱了光合效率;净光合速率(Pn)与蒸腾速率(Tr)极显著相关,螺旋环剥显著降低了叶片的Tr,Pn也下降但差异不显著,蒸腾作用减弱的程度比光合作用减弱的程度大;对照叶片的Pn和Tr日变化为单峰曲线型,14:00时达最高峰,螺旋环剥叶片的Pn和Tr在13:00时有明显的午休现象,气孔限制是午休的主要因素;相同处理的有果枝叶片,其日均Pn和Tr都高于无果枝叶片,说明果实的存在可提高‘桂味’荔枝的Pn和Tr。     

Girdling of early season ‘Mayfire’ nectarine trees

The effect of four times of limb girdling on fruit and tree response was examined on ‘Mayfire’ nectarine (Prunus persica (L.) Batsch). Girdling prior to Stage II of fruit growth reduced the lag phase associated with Stage II, and caused peak fruit growth rates to occur earlier in the season than on later girdled or ungirdled trees. Optimum response was obtained by girdling prior to Stage II, when fruit seed length was approximately 10 mm. Girdling at this time increased fruit weight by 22.5% and more than doubled the percentage of fruit in the largest three size categories. Maturity, measured as soluble solids concentration, was increased by 42%. Shoot extension growth was reduced only by early girdling. Leaf weight per unit area was increased, and leaf nutrient concentrations were decreased by all girdling treatments. Leaf conductance to water vapour (g,) was not affected when measured 8 days prior to and 78 days after harvest. Fifteen days after harvest, g, was decreased in all girdling treatments.     

Effects of pruning intensity on the biochemical status of shoot buds in three mango (Mangifera indica L.) cultivars planted at high density

Summary

Mango (Mangifera indica L.) trees grown at high density show a decline in flowering and fruiting after good fruiting years as a result of various factors. Annual pruning can restore production and productivity in such trees. Chlorophyll, total sugars (TS), total phenolics (TP), and proline contents as well as polyphenol oxidase (PPO) activities, were measured in the 2005–2006 and 2006–2007 seasons in shoot buds with a few leaves in three mango cultivars (‘Amrapali’, ‘Mallika’, and ‘Dashehari’). Trees were grown at high density in an orchard and the aforesaid parameters were measured 1 month after different degrees of pruning (Stage I) and after subsequent fruit bud differentiation (FBD; Stage II). Severely-pruned mango trees had the highest contents of chlorophyll a, while chlorophyll b and total chlorophyll contents were found to be highest in moderately-pruned trees. Lightly-pruned trees had the highest contents of reducing sugars (RS), whereas TS contents were highest in severely-pruned trees. The contents of RS and TS increased in shoot buds during the FBD stage. A moderate intensity of pruning significantly increased TP contents, while the lowest TP contents were recorded in non-pruned trees. ‘Off’-year shoots had higher TP contents than ‘on’-year shoots. Irrespective of pruning intensity, shoot buds of ‘Mallika’ trees had the highest PPO activities, with lower levels in ‘Amrapali’ and ‘Dashehari’ shoot buds. PPO activities were reduced at the FBD stage in ‘on’-year shoots. Severely-pruned trees had the highest PPO activities, while the lowest PPO activities were recorded in lightly-pruned trees. Shoot bud proline contents were found to be highest in non-pruned trees, and decreased with increasing pruning intensity. Thus moderate pruning can be adopted in high density orchards to obtain sustainable production with improved maintenance of canopy architecture.     

从调节源—库关系看环剥对荔枝幼树根梢生长与坐果的调控

荔枝常因幼树花而不实而颗粒无收.糯米糍品种4年生幼树盛花期主干环剥,并保持不愈合至采果.对照树全年根、梢各有3个生长期,环剥树采前无根、梢生长;对照树有4次生理落果峰,环剥树第2、3落果峰不明显,采前落果峰也很低.研究认为荔枝幼树根系的“库”力在竞争中占优势,根与梢的生长相克又相促,果实在竞争中处于劣势,环剥完全抑制了根与梢的生长,使果实在“库”力的竞争中得以转弱为强.     

荔枝环剥时期对新梢生长及碳素储备的影响

 枝梢环剥显著抑制了‘怀枝’荔枝新梢的生长，并导致射线细胞和髓部大量积累淀粉。梢芽萌发或伸长前环剥可完全抑制新梢生长，而新梢快速伸长期环剥对其抑制效应最弱。秋季环剥对新梢的抑制和对淀粉积累的促进效应明显高于春季环剥。环剥口以上的老叶面积和环剥位置并不影响环剥对新梢生长的抑制效应和促进淀粉的积累效应，但环剥口以上单位枝梢长度的叶面积与淀粉含量呈显著正相关。     

A role for carbohydrate levels in the control of flowering in citrus

Girdling in October of small or large fruitless branches increased 2–3-fold both starch content of leaves and flower numbers as compared with ungirdled ‘Murcott’ mandarin trees. Autumn girdling and GA₃ treatments were both effective and additive in increasing starch contents of leaves and twigs of ‘Shamouti’ orange trees. GA₃, however, had the expected effect of depressing the reproductive inflorescences in both girdled and ungirdled branches, while girdling had the opposite effect. Girdling and fruit removal in October also additively and dramatically increased flower production in ‘Murcott’. Lowtemperature regimes in a phytotron caused young ‘Minneola’ budlings to flower earlier in the season and more profusely, while having no effect on starch content of leaves and twigs. The interactions of increased carbohydrate content and gibberellin in the control of flower formation in citrus are discussed.     

Girdling of ‘Fuerte’ avocado in subtropical Australia

Girdled limbs of ‘Fuerte’ avocado produced a bigger crop than controls for 3 consecutive years. Limbs girdled for 4 consecutive years yielded the same as the control, but healed slowly. Yield was maintained in the year after girdling was stopped. The number of seedless fruit was not increased by girdling.     

环剥对冬枣叶片内有机营养物质含量的影响

采用不同的环剥宽度,于盛花期对4～5a生的冬枣树体进行处理,测定叶片内有机营养物质的含量,同时调查当年树体的坐果率和翌年的萌芽率。结果表明:环剥宽度为1.0cm的树体有助于坐果率提高和树体营养回流的实现。     

Effect of CPPU on fruit and shoot growth of apple

The effects of CPPU on the growth of fruits and bourse shoots of apple were examined by targeted applications of 20 mg I“1 CPPU to fruitlets and/or bourse-shoot and spur leaves. Treating fruitlets and fruitlets-plus-leaves stimulated fruit growth to a similar extent; fruit growth rate was temporarily suppressed when only the leaves were treated. Conversely, bourse shoot growth was stimulated by leaf and leaf-plus-fruit treatments. All CPPU applications reduced the content of fruit soluble solids and induced a paler yellowish- green fruit ground colour.     

The Strawberry Aphid,Pentatrichopus Fragariae (Theob.), in North Wales,with Special Reference to the Maintenance of Healthy Strawberry Stocks in Non-Fruit-Growing Areas

Summary

Excessive premature abscission of developing fruitlets in UK cherry orchards often results in low fruit yields. An improvement in our understanding of the underlying causes of embryo abortion and fruitlet abscission will help rationalize effective remedies to this problem. The aim of this study was to determine the effects of limiting the availability of leaf-derived assimilates, during critical stages of fruitlet development, on the severity of fruitlet abscission. Experimentally, this was achieved by isolating individual “spur units” (short shoots (<10 cm) with leaves and fruit) from the tree by girdling (severing the phloem connections) branches on either side of the unit. In this way, the developing fruitlets within the associated spur would be able to derive their assimilates only from the associated spur leaves. Spur units with different total leaf areas and variable numbers of developing fruitlets were chosen to achieve a wide range of potential source and sink strengths. The spurs analysed varied in leaf number from 4–9 leaves as spur leaf area increased. The largest variability in the spur leaf area number relationship occurred in spurs with 6–7 leaves. When initially determining the total leaf area per spur in May, there was no obvious relationship with fruit number per spur. Subsequent analysis of the relationship between spur leaf area and fruit number per cluster showed that fruit had been lost from spurs with the smallest leaf areas. Spurs girdled later in the season in June also showed no obvious relationship between spur leaf area and fruit number. As with spurs girdled in May, those manipulated in June lost fruit from spurs with small leaf areas. By July, there was a positive curvilinear relationship between spur leaf area and fruit number for girdled spurs. Neither total nor average fruit fresh weight per spur, at harvest, could be related to spur leaf area. The average individual fresh weight of fruit in a spur was, however, limited by the number of fruit within that spur. When spurs were girdled, fruit loss was shown to take place preferentially where the spur leaf area per fruit was low. From this analysis, it was possible to predict which girdled spurs would lose fruit, using the calculated ratio of spur leaf area per fruit. It is concluded that fruit retention, not size, appears to be limited by the availability of leaf-derived assimilates.     

Growth of Vitis vinifera L. and Vitis aestivalis Michx. as Affected by Temperature

Abstract

Four European (Vitis vinifera L.) winegrape cvs., ‘Semillon’, ‘Pinot Noir,’ ‘Chardonnay’, and ‘Cabernet Sauvignon’, and one American (Vitis aestivalis Michx.) winegrape cv. ‘Cynthiana’, were subjected to three temperature regimes in growth chambers set at 20/15°C, 30/ 25°C, or 40/35°C, for 16/8 hr day/night to determine the influence of temperatures on vine growth and development. In general, the best temperature for shoot and root growth 28 days after temperature treatments was 20/15°C for ‘Semillon’, ‘Cabernet Sauvignon’, and ‘Cynthiana’, and 30/25°C for ‘Pinot Noir’ and ‘Chardonnay’. Although 40/35°C reduced number of leaves, shoots, tendrils, and internodes, total leaf area (LA), and total shoot biomass of all the cultivars, the reduction was more pronounced in ‘Cynthiana’ than in the European cultivars. The average reduction in number of leaves at 40/35°C for the European cultivars was 47%, compared with 92% for ‘Cynthiana’. The two types of grapes adapted differently to high temperature. Shoot growth in the European cultivars continued under high temperature, whereas growth ceased in ‘Cynthiana’. Roots of ‘Cynthiana’, however, were less susceptible to the adverse effect of high temperatures than were the shoots. This study shows that the European cultivars were relatively more tolerant to high temperature than the American cultivar and they have a potential for production of wine in the climate of south central Kansas.     

红富士苹果枝条下垂处理对~(15)N尿素吸收、分配及利用的影响

以7年生红富士苹果(Malus domestica Borkh.‘RedFuji’)/平邑甜茶(Malushupehensis)为试材,研究枝条下垂处理对春季土施15N尿素的吸收、分配与利用的影响。结果表明:枝条下垂处理植株的根系从肥料中吸收分配到的15N量对根系全氮量的贡献率(Ndff)均低于对照,其中细根在多个物候期差异显著,而粗根在果实膨大期后差异显著;中短梢及中短梢叶的Ndff差异不显著;处理果实及长梢和长梢叶的Ndff在果实采收前均显著低于对照;处理植株多年生器官的Ndff在果实采收后显著高于对照。从15N分配率看,处理植株的中短梢一直显著高于对照,果实在膨大期后显著高于对照;长梢在果实采收前显著低于对照。处理植株的15N利用率低于对照,在果实膨大期后差异显著,两者植株15N利用率在果实采收后分别为21.083%和26.495%。     

‘粤引无核荔’退化果形成原因初探

 对‘粤引无核荔’ (Litchi chinensis Sonn. ‘YueyinWuheli’) 正常果和退化果果皮的内源激素进行测定, 同时比较正常果和退化果结果母枝叶片中的碳水化合物。结果表明, 在谢花后56 d和66 d, 正常果果皮中的IAA /ABA、GA_{1 + 3} /ABA、iPAs/ABA值均高于退化果; 在谢花后56 d, 正常果结果母枝叶片的淀粉含量高于退化果; 在谢花后66 d, 正常果结果母枝的蔗糖含量高于退化果。认为退化果中IAA、GA和细胞分裂素与ABA的比值处于相对低的水平, 以及退化果结果母枝叶片碳水化合物水平相对较低可能是退化果形成的原因。     

Influence of shoot age on floral development and early fruit set in avocado (Persea americana Mill.) cv. Hass

Floral bud development, early fruit set, bud size, leaf nitrogen and shoot starch content were recorded in spring, summer and autumn shoots of ‘Hass’ avocado (Persea americana Mill.). Floral initiation occurred in late autumn, but only in buds on terminal shoots (the last-formed shoot module on a terminal or axillary growth axis). In branching systems with three growth flushes, more flowers were produced and more fruit set on autumn and summer, than on spring flush terminal shoots. Floral development and leaf nitrogen accumulation occurred later in autumn than in summer shoots, but leaf numbers, dry and fresh weights, starch content of wood, mean floral status at anthesis and anthesis date were similar. The results suggest that nitrogen and starch were present in excess during floral development, and that shoot age did not influence the ability of a shoot to flower and set fruit, provided the shoot had sufficient vigour to produce new shoot growth in spring.     

“国庆1号”温州蜜柑结果母枝状况与结果的关系

选用20 a生“国庆一号”温州蜜柑盛果多花中庸树,随机取样调查结果母枝粗度、长度、其上有叶结果枝和无叶结果枝数量、有叶结果枝叶数、长度以及它们的坐果率.结果表明:有叶结果枝及无叶结果枝数不随结果母枝粗度的增加而有规律的增减,但随母枝长度的增加有减少的趋势.结果母枝粗度在0.4～0.5 cm范围内,有叶结果枝和无叶结果枝坐果率都最高,分别为7.8％和27.5％.结果母枝长度在0.1～10 cm范围内,有叶结果枝和无叶结果枝坐果率都最高,分别为7.0％和21.5％.结果母枝粗度与有叶结果枝及无叶结果枝坐果率无显著相关关系.母枝长度与有叶结果枝坐果率无显著相关关系,但与无叶结果枝坐果率呈显著正相关.有叶结果枝叶片数越少的有叶结果枝数反而越多,有叶结果枝叶数与有叶结果枝数呈显著正相关;总的来说,叶数越多,有叶结果枝坐果率越高.以短有叶结果枝数量大,但有叶结果枝长度与有叶结果枝坐果率呈显著正相关.     

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%.