Effect of fruit on flowering in relation to biennial bearing in sweet orange (Citrus sinensis)

Flowering and fruit-setting in the sweet orange cv. ‘Late Valencia’ were observed for three consecutive seasons that comprised two “off-years” and one “on-year”. Twice as many flowers per unit area of tree canopy were observed in the “on-year” as in the two “off-years”. There was a significant negative correlation between the yield of the previous crop and the number of flowers per square yard of tree canopy.

There were no significant differences between an “off-year” and an “on-year” in the proportions of inflorescences classified according to the number of flowers and number of leaves per inflorescence. Furthermore, the previous crop had no direct effect on fruit-set, the percentage fruit-set being similar in all three seasons.

Observations made during blossoming, when the trees were bearing an “on-year” crop, showed that practically no flowers were produced on fruit-bearing wood. The few inflorescences that were recorded on fruit-bearing wood tended to be of the leafless types.

It is suggested that the cause of biennial bearing in sweet orange is the diffusion of a flower inhibitor, possibly a gibberellin-like substance, from the fruit into the wood on which it is borne.     

Removal of flowers or inflorescences affects ‘Barnea’ olive fruitlet post-anthesis abscission

A typical olive (Olea europaea L.) inflorescence consists of about 20 flowers. However, in many cultivars, only one fruit develops. This is due to massive abscission of flowers and fruitlets, which occurs during the first month after anthesis. In this study, we used the olive cultivar 'Barnea' to characterize the abscission mechanism and to try to increase fruit set by increasing the number of developed fruit per inflorescence. Removing the lateral flowers 3 weeks before anthesis increased fruit set by more than 50%. Removing all inflorescences but one from a branch increased the number of developed fruits from 0.93 to 2.8 during 2017 and from 0.91 to 3.34 fruits per inflorescence in 2018. Sugar quantification in the pistil revealed that starch level is high on the day of anthesis and low 25 days later in abscised as well as in developed fruit. Soluble carbohydrates are low on the day of anthesis, low in abscised flowers/fruitlets 25 days after anthesis and high in developed fruit. Screening the natural variation found in the Israeli germplasm collection revealed that in most cultivars less than one fruit per inflorescence has developed. However, there are unique cultivars with a higher fruit set.     

梨子花发育对果实品质的影响

选择梨主栽品种‘丰水’、‘黄金’、‘新高’、‘鸭梨’、‘茌梨’和‘绿宝石’等为试材,对梨子花发育状况以及对果实品质的影响进行了调查研究。结果显示：梨不同品种子花发生率差异明显,‘丰水’、‘黄金’、‘新高’等砂梨系统品种子花发生率比‘鸭梨’、‘茌梨’和‘绿宝石’等白梨系统品种高;在结果枝类型上,短果枝的子花发生率比长果枝高;在结果母枝类型及生长势的强弱上,1年生弱枝的子花发生率比强枝高,2年生枝比3年生枝高;在同一花枝上中部子花发生率高;子花的开花期比母花晚 1 ~ 2 d,小花数在3 ~ 6朵之间,开花顺序与母花相反,为中心花先开,中心果发育最快。子花所结果实比母花果实小,商品价值低。因此,梨生产上子花的及早摘除有利于果品质量的提高。     

盆栽观赏苹果疏花促果调控试验初报

在花期对盆栽‘冬红果’和‘舞美’采取不同疏花方式进行调控,试验结果表明:‘冬红果’采取每隔5个花序留1花序,其余4个疏除和隔12个花序集中留3个花序,其余9个花序疏除,花枝上端(1/4)全部疏除,留花枝侧下花序处理方法,坐果数和单果重较对照分别提高30.1%、24.2%,2种方法之间无显著差异。‘舞美’采取每隔10cm留1个花序,每花序留中心花,其余花序和花朵疏除,所留花朵位于枝条侧下位和每隔25cm留3个花序,留侧下花序,每花序留中心花,其余全部疏除的处理方法,较对照坐果率和单果重分别提高26.2%、36.11%;2种处理方法效果显著好于对照。该试验找出了适合2品种盆栽条件下的花期最佳疏花促果调控措施。     

Fruit set is inversely related to flower and fruit weight in olive (Olea europaea L.)

Fruit weight is strongly correlated to ovary weight in olive as big-fruited cultivars have larger ovaries and flowers at bloom. We tested the hypothesis that larger ovaries imply stronger sinks and therefore reduce fruit set, expressed as number of fruits. Flower/fruit load per centimeter of shoot was assessed every month from flowering to harvest, on sample shoots of many different olive cultivars differing in fruit size. Data were taken for two years: 2007 and 2008. Additionally, in 2008, a fruit thinning experiment was carried out by leaving a single fruit per shoot, to assess the maximum potential fruit weight achievable by each cultivar. Results indicated that fruit size was mostly genetically determined as thinned fruits of small-fruited cultivars, although bigger than control fruits, never got as big as fruits from large-fruited cultivars, confirming that large ovaries are a prerequisite for large fruits. Among all cultivars, the number of flowers per inflorescence, the number of inflorescences, and the number of flowers per centimeter of shoot were not correlated to average flower weight while total flower mass per centimeter of shoot was positively correlated to average flower weight (i.e. large flowered/fruited cultivars had greater total flower mass). However, one month after bloom and thereafter, all parameters were negatively and exponentially correlated with fruit average weight across cultivars, except fruit mass per centimeter of shoot which was generally not correlated to fruit average weight, except in one year, at harvest, when fruit mass per centimeter of shoot was positively correlated to fruit average weight. These results suggest that fruit set is a consequence of, and inversely proportional to flower/fruit size in olive.     

The Effect of Partial Defoliation at Different Times in the Season on Fruit Drop and Shoot Growth in Lord Lambourne Apple Trees

Six-branched trees were deblossomed on alternate branches and various defoliation treatments given. For the period of 7 to 30 days from the time of treatment, defoliations increased the compound-interest rates of fruit drop. After this period these rates of drop became equal to those of untreated trees and the relative differences in crop numbers established by this time persisted until harvest though the actual numbers still fell. The earlier in the season that the defoliations were applied the greater were the relative differences. The removal of spur leaves from branches bearing fruit caused greater drop than the removal of spur leaves from neighbouring deblossomed branches. The removal of leaves from extension and bourse shoots of fruiting or deblossomed branches had no significant effect upon fruit drop or shoot growth.

The removal of all flowers from alternate branches at mouse-ear caused more shoots to grow from these branches than from branches allowed to fruit. Removal, at pink bud, of spur leaves from either fruiting or non-fruiting branches increased the number of shoots on both branches, but removal deferred till later in the season had no effect.     

A Study of the Development of the First Inflorescence of Glasshouse Tomatoes

When seedlings of the Potentate variety of glasshouse tomato began growth at a time of year when the day-length was less than twelve hours and decreasing, development of the first inflorescence ceased at an early stage. When growth began at a time of year when the day-length was more than twelve hours, or less than twelve hours and increasing, normal development of the first inflorescence from initiation to ovary swelling occurred.

When these normal inflorescences reached antbesis and the ovaries began to swell at a time of year when the day-length was more than twelve hours, a large constant percentage of the buds reflexed their petals and nearly all such flowers set fruit. When the day-length became less than twelve hours anthesis and ovary swelling rapidly decreased and ceased.     

The relationship between yield and assimilate supply in lychee (Litchi chinensis Sonn.)

Summary

Experiments were conducted on lychee (Litchi chinensis Sonn.) in subtropical Australia (lat. 27° –29°S) to evaluate the role of assimilates on fruit retention. All the leaves of the last flush, all the leaves of the previous flush (about eight leaves per terminal shoot), or all the old leaves were removed from trees. Medium (3–5.cm diameter) or large branches (5–10.cm diameter) were girdled and defoliated after fruit set, and fruit retention compared with ungirdled and undefoliated branches. Other branches were girdled and defoliated between anthesis and fruit harvest. Finally, 20, 50 or 80% of the flowering panicles were defruited on large trees. Defoliated trees had 35 to 45% lower yields than the controls. This was despite the treatment with all the old leaves removed having a much lower leaf area index than the other defoliation treatments (1.7 vs. 2.3 and 2.8). Leaves next to the inflorescences are more important for yield than the older leaves. Fruit retention was very low on girdled branches that had been defoliated, especially when the leaves were removed in the first 20.d after anthesis. This suggests that the yields of girdled branches were determined by the availability of assimilates soon after fruit set. In contrast, the number of fruit retained on ungirdled branches was unrelated to the number of leaves, with defoliation having no effect on yield. Fruit on these branches were supported by resources from elsewhere in the tree. Thinned trees had similar yields to those of unthinned plots (65–82.kg tree^–1). Thinning apparently increased fruit retention in the remaining clusters, under a higher leaf:fruit ratio. There were large differences in the concentrations of starch in the tree, and seasonal changes, with starch declining from flowering to fruit harvest. In contrast, there were only small responses to the treatments, suggesting that the fruit were mainly dependent on current photosynthesis. Photosynthesis in the leaves behind the fruit clusters was more important than photosynthesis in the older shaded leaves.     

Inflorescence architecture of olive

The influence of flower position on the inflorescence on opening day, gender, and petal persistence was studied in three olive cultivars: Manzanillo, Mission, and Frantoio. In each cultivar, 45 inflorescences were checked every morning from flower opening to petal fall. Perfect flowers opened mainly in the beginning of the flower opening period, and staminate flowers opened later. Flower position on the inflorescence had a highly significant effect on the opening day in all cultivars. Terminal flowers and the flowers located on the primary branches opened earlier than the flowers located on the secondary branches. Flower position had also a highly significant effect on gender in Manzanillo and Mission. In Manzanillo, the secondary branches had fewer perfect flowers than the primary branches. In Mission, the secondary branches had no perfect flowers at all. Among the primary branches, the branch arising immediately next to the terminal flower had the latest flowers to open and the lowest percent of perfect flowers. In Manzanillo, perfect flowers had significantly longer petal persistence than staminate flowers. To study flower competition within the inflorescence, the distal half of 120 inflorescences, on which the flowers tend to be perfect, in three trees of Manzanillo were removed about 1 month before full bloom. There was a highly significant effect on the percent of perfect flowers that opened on the proximal half. Flower competition may be a reason for pistil abortion in flowers located on secondary branches.     

Effect of the light intensity on forcing of the strawberry cultivar ‘Glasa’

Plants of ‘Glasa’ were forced early in growth rooms at 14°C under a 16-hour day consisting of 8 hours of mercury light, light intensities 12, 24 or 36 W m^?2, supplemented by 8 hours of incandescent light, intensity 0.8 W m^?2. Light intensity affected the flowering-date, the number of inflorescences, the number of flowers per inflorescence, stamen development and fruit set. For successful forcing, a light intensity of at least 24 W m^?2 is necessary.     

Influences of day and night temperatures on flowering of Fragaria x ananassa Duch., cvs. Korona and Elsanta,at different photoperiods

The effects of photoperiod (12, 13, 14, 15 or 16 h), day temperature (12, 15, 18, 24 or 27 °C) and night temperature (6, 9 or 12 °C) and their interactions on flower and inflorescence emergence were investigated by exposing 4 week old runner plants of strawberry cvs. Korona and Elsanta during a period of 3 weeks. A daily photoperiod of 12 or 13 h resulted in the highest number of plants with emerged flowers. A photoperiod of 14 h or more strongly reduced this number, while no flowers emerged at a photoperiod of 16 h. Plants exposed to photoperiods of 12 or 13 h flowered earlier and had longer flower trusses. A day temperature of 18 °C and/or a night temperature of 12 °C were optimal for plants to emerge flowers and resulted in the shortest time to flowering. A night temperature of 6 °C strongly reduced the number of plants that emerged flowers, especially when combined with lower day temperatures. Photoperiod and temperature had no effect on the number of inflorescences, all flowering plants produced on average one inflorescence. The number of flowers on the inflorescence increased with decreasing day temperature and when photoperiod was raised from 12 to 15 h. In general, ‘Korona’ was more sensitive to photoperiod and temperature as ‘Elsanta’, and had a lower optimal day temperature for flower emergence. Results of this experiment may be used to produce high quality plant material or to define optimal conditions when combining flower induction and fruit production.     

Interactions of photoperiod,temperature, duration of short-day treatment and plant age on flowering of Fragaria x ananassa Duch. cv. Korona

The effects of photoperiod (10, 12, 16, 20 or 24 h), day-temperature (12, 15, 18, 24 or 30 °C), the number of short days (14, 21 or 28 days), plant age (4, 8 or 12 weeks) and their interactions on flower and inflorescence emergence were investigated in strawberry cv. Korona. No flowers emerged in plants exposed to photoperiods of 16, 20 or 24 h or to a short-day treatment for 14 days. All plants exposed to short days at daily photoperiods of 10 or 12 h for 21 days or longer, emerged flowers at temperatures between 12 and 18 °C. A further increase in temperature led to a drastic decrease in the total number of flowers per plant. A short-day treatment (10 or 12 h photoperiod) of 28 days resulted in highest numbers of inflorescences and flowers per plant, while a short-day treatment of 21 days resulted in the highest numbers of flowers per inflorescence. Complete flower induction was observed in only 4-week-old runner plants. The number of inflorescences and the number of flowers per inflorescence increased with plant age. However, the start of flowering was delayed with increasing plant age.     

Characterization and genetic linkage mapping of the horticulturally important mutation leafless inflorescence (lli) in periwinkle Catharanthus roseus

Catharanthus roseus is a seasonal to perennial garden plant and the exclusive source of the anticancer drugs vincristine and vinblastine. Its horticultural importance is due to the compound racemose inflorescence architecture of branches in which pairs of prominent flowers are subtended by one of the two leaves per node. Here is reported the construction of a molecular framework genetic linkage map and mapping on it of the LEAF-LESS INFLORESCENCE (LLI) locus. It is quantitatively shown that the adult lli mutant plants produce altered inflorescence of improved horticultural value, wherein axes are excessively branched, two flowers are formed per node that are bare of subtending leaves, and several times more open flowers are displayed each day, as compared to LLI plants.     

Salinity effects on strawberry plants grown in rockwool. I. Growth and leaf water relations

Comparison of four everbearing or day-neutral cultivars of strawberry (Rapella, Ostara, Fern and Selva) grown under glasshouse conditions in rockwool showed Rapella to accumulate the greatest shoot dry weight and leaf number together with the production of few stolons but many relatively large fruits per inflorescence. Subsequent studies with cv. Rapella found that increasing the salinity of the irrigation supply from 2.5 to 5.7 and to 8.5 mS cm"1, by the addition of NaCl, progressively reduced leaf number emerged and final leaf area by up to 36% and 48% respectively, after 100 d of treatment. Shoot dry weight, excluding fruits, was reduced by up to 47%. The number of crowns (lateral branches) was reduced from 11 in the lowest salinity to 8 and 7 at the higher salinity levels. Leaf water potential, \)/w, was reduced by up to 0.23 MPa in young leaves and 0.36 MPa in older leaves. Leaf osmotic potential, xj/^, was decreased by up to 0.14 MPa in younger leaves following salinity treatment at 8.0 mS cm-1. Consequently leaf turgor was reduced more in older than in younger leaves. Inflorescence number was reduced from 27 to 20 and 17. Within the remaining inflorescences however, flower numbers, fruit numbers and duration of fruit ripening were not affected. A marked decrease in the fresh weight of the fruit was detected in both higher salinity treatments but fruit dry weight was only slightly reduced.     

Effect of GA3, CCC defoliation and quantum flux density on growth and flowering in Pelargonium × hortorum

In vegetatively propagated Pelargonium × hortorum plants, formation of axillary shoots and initiation of inflorescences and leaves were promoted by an increase in quantum flux density, whereas application of GA₃ had a negative effect. Application of CCC caused an increase in number of axillary shoots and consequently an increase in number of inflorescences and leaves per plant.Dry weight increase was promoted by an increase in quantum flux density, unaffected by GA₃ treatment, but inhibited by CCC treatment. Moreover, continuous removal of the oldest leaves reduced the number of inflorescences, leaves, axillary shoots and dry weight. The changes in inflorescence and leaf initiation could not be definitely correlated to the changes in dry weight increase.     

Flowering-pattern and yield components at inflorescence nodes of snap bean as affected by irrigation and plant density

This paper reports the results of a 2 × 2 factorial experiment on bush snap beans ‘Oregon 1604’. The treatments were 2 contrasted irrigation regimes and 2 contrasted plant densities, and were applied in 1978 and repeated in 1979. Data were collected on the number of flowers and pods, and pod size, at each node of the terminal inflorescence (6-T) of the main stem, and at each node of the oldest inflorescence (2-A) at Node 2. High and low plant densities were 45 and 18 plants m^?2 in 1978 and 54 and 33 plants m^?2 in 1979. High temperatures, frequently above 32°C, prevailed during bloom and pod development in 1978, but for the most part occurred only during the week prior to bloom in 1979. Inflorescences 6-T and 2-A usually formed 4 and 3 RN's, respectively, in 1978 and 3 and 2 RN's in 1979. The flowers at the proximal nodes of each inflorescence all opened within a few days of one another (duration of flowering at proximal nodes between 3 and 5 days); the flowering-periods of adjacent nodes overlapped, and the flowering period increased acropetally within the inflorescence (duration of flowering at distal nodes between 7 and 13 days). In general, number of flowers, pods formed, pods harvested and percent set decreased acropetally within each inflorescence. The rate of acropetal decline was lessened by high irrigation or low plant density. In both years, high irrigation increased the percent set of all RN's of the 2-A inflorescences, but few other consistent effects between years were observed. The 2 most proximal RN's together produced 93% or more of the yield of each inflorescence. High irrigation significantly increased the total number of pods harvested from these RN's of inflorescences 6-T and 2-A, and low density had a similar effect on 2-A.     

板栗雌雄花发育相关的MADS-box基因发掘与表达分析

为筛选板栗混合花序中雌雄花形成与发育关键基因,基于板栗雌雄花表达谱测序结果,从差异表达基因中分离到17个MADS-box基因。通过序列结构分析,发现其中2个基因缺少半保守的K盒,为Ⅰ型MADS-box基因,另外15个基因为Ⅱ型MADS-box基因。系统进化关系分析显示,13个包含完整读码框的MADS-box基因中有2个B类基因,1个C/D类基因和3个E类基因。荧光定量PCR结果证实这些MADS-box基因在板栗早期混合花序中的雌雄花之间表达差异显著（变化倍数 > 2）,且部分B、C/D和E类基因在板栗幼叶、纯雄花和雌花中的表达变化趋势相似,推测这些MADS-box基因在板栗雌雄花形成和发育中起重要调控作用。     

Effects of fruit thinning,pollination and paclobutrazol on fruit set and size of persimmon (Diospyros kaki L.) in subtropical Australia

Summary

A factorial combination of three cultural factors (± hand-pollination, ± growth retardant, ± fruit thinning) were evaluated for their effects on fruit set and fruit size of ‘Fuyu’ persimmon (Diospyros kaki L.) in subtropical Australia (Lat. 27° S). Treatments were applied to individual shoots on mature seven year old trees. Fruit set of pollinated flowers was high compared with non-pollinated flowers (91% vs. 47%). Pollinated fruit also grew faster at all stages of fruit development and, at harvest, fresh weights were 25% heavier. Palcobutrazol significantly (P<0.05) increased fruit weight by 7% compared with controls but did not increase fruit set. Irrespective of treatment, fruit weight was not correlated (r<0.3, n.s.) with shoot length, number of nodes per shoot, fruit nodal position, shoot dry weight, leaf area per shoot, and number of leaves per shoot. Fruit fresh weight was only poorly correlated with shoot base diameter (r = 0.41*). Pollinated fruit had significantly (P<0.05) higher concentrations of nutrients (N, K, Ca, and Zn).     

Effect of triacontanol on production and quality of flowers of Chrysanthemum morifolium Ramat

Two cultivars of Chrysanthemum morifolium, ‘Golden Horim’ and ‘Golden Miquel’, were cultivated in nutrient solution containing the growth regulator triacontanol. The vegetative growth, production of inflorescences and quality of flowers were measured. The dry weight of the whole plant and the shoot from both cultivars increased. The number of inflorescences per plant and the number of flowers per inflorescence also increased in response to triacontanol treatment, which in turn enhanced the quality of flowers in accordance with the standards defined by sales-quality groups. The number of flowers of superior quality was more than doubled.     

早熟温州蜜柑的开花坐果规律研究

以早熟温州蜜柑为试材,连续4a(2008～2011)调查早熟温州蜜柑的开花结果习性,对其开花坐果动态影响因素进行研究。结果表明:各类结果母枝的开花量和坐果率有明显差异,早秋梢结果母枝、夏梢结果母枝和晚秋梢结果母枝的效果之间,有叶花的坐果率与有叶花的坐果量之间存在显著差异水平,而晚秋梢结果母枝与春梢结果母枝的效果之间不存在显著差异水平;1a有4次落花落果高峰期:第1次发生在5月13～27日;第2次发生在6月9～16日;第3次发生在8月11～18日;第4次发生在10月6～13日;在结果母梢上不同营养梢比例直接影响坐果率,营养梢的比例越小,其坐果率越高;栽植密度大或蛆花率大的果园,坐果率都较低;不同结果母枝长度能够影响坐果率;有叶花枝的叶片数量影响坐果率,4片叶的坐果率最高;留梢的位置在母枝的顶端和控制营养梢的数量越大,其效果越明显;建议生产上提高树体有叶花的比例和调节营养梢的发生量,从而缓解梢果矛盾和提高坐果率。