Environmental control of growth and flowering of Rubus idaeus L. cv. Glen Ample

Environmental control of the annual growth cycle of ‘Glen Ample’ raspberry has been studied in order to facilitate crop manipulation for out-of-season production. Plants propagated from root buds were raised in long days (LD) at 21 °C and then exposed to different temperature and daylength conditions at varying ages. Shoot growth was monitored by weekly measurements and floral initiation by regular sampling and examination of axillary bud #5. Under natural summer daylight conditions at 60°N shoot growth was nearly doubled at 21 °C compared with 15 °C, while at 9 °C one half of the plants ceased growing and formed flower buds at midsummer. Developing shoots have a juvenile phase and could not be induced to flower before the 15-leaf stage. No significant reduction in induction requirements was found in larger plants. Plants exposed to natural light conditions from 10th August, had an immediate growth suppression at 9 and 12 °C with complete cessation after 4 weeks (by September 7). This coincided with the first appearance of floral primordia. At 15 °C both growth cessation and floral initiation occurred 2 weeks later (by September 21), while at 18 °C continuous growth with no floral initiation was maintained until early November when the photoperiod had fallen below 9 h. The critical photoperiod for growth cessation and floral initiation at 15 °C was 15 h. Plants exposed to 10-h photoperiods at 9 °C for 2–4 weeks had a transient growth suppression followed by resumed growth under subsequent high temperature and LD conditions, while exposure for 5 or 6 weeks resulted in complete growth cessation and dormancy induction. The critical induction period for floral initiation was 3 weeks although no transitional changes were visible in the bud before week 4. When exposed to inductive conditions for marginal periods of 3 or 4 weeks, an increasing proportion of the plants (20% and 67%, respectively), behaved as primocane flowering cultivars with recurrent growth and terminal flowering. It is concluded that growth cessation and floral initiation in raspberry are jointly controlled by low temperature and short day conditions and coincide in time as parallel outputs from the same internal induction mechanism.     

Effect of photoperiod and light integral on flowering and growth of Eustoma grandiflorum (Raf.) Shinn.

The aim of the study was to examine the effects of different photoperiod and light integral on floral initiation, development and subsequent growth of Eustoma grandiflorum (Raf.) Shinn. Six-weeks-old seedlings of ‘Echo Blue’ and ‘Fuji Deep Blue’ were placed under short day (SD, 10 h) and were transferred to long days (LD, 20 h) at 2-week intervals from 6 to 14 weeks after seeding. Plants initiated flower buds regardless of light regimes. Flower bud initiation was delayed by SD compared to LD; plants transferred after 6 weeks from seeding initiated flower buds at least 21 and 10 days earlier at LD at high (HL) and low (LL) daily light integral, respectively, compared to those at SD. Light regimes had little or no effect on time to flower bud development after initiation. Thus, it seems likely that LD and HL affected the initiation rather than development. Both the photoperiod and light integral strongly influenced the subsequent growth after initiation. SD delayed the time to visible bud (VB), increased the number of nodes to first open flower, number of branches, stem diameter and shoot dry weight compared to LD. HL promoted flowering and increased several shoot characteristics and flowering compared to LL.The results indicate that Eustoma is a quantitative long-day plant. LD, and more specifically HL, enhanced flower bud initiation, development and subsequent growth. An initial SD period is preferred to increase the number of branches, number of flowering buds and flowers, stem diameter and shoot dry weight.     

紫花地丁开放花与闭锁花的发育及可溶性糖与淀粉含量的研究

紫花地丁(Viola philippica)为典型的两型花自花受精植物,具有开放花和闭锁花混合繁育系统。通过对开放花和闭锁花花芽形态发育的比较发现:开放花与闭锁花在花芽发育早期形态相似,4轮花器官原基均正常发生。出现明显差异的时期为4轮花器官原基形成以后,小孢子发育时期为产孢细胞阶段,开放花的5个花瓣与5枚雄蕊继续发育,每个雄蕊有4个花药室;而闭锁花只有2枚雄蕊继续发育,每个雄蕊有2个花药室,其余雄蕊与所有的花瓣依然为器官原基状态,不再发育。通过对花芽与叶片可溶性糖与淀粉含量的检测发现,花器官原基形成之后,开放花与闭锁花形态出现明显差异阶段开始,随着花芽的发育,可溶性糖与淀粉含量均呈上升趋势,且开放花花芽中的含量均明显高于对应发育阶段闭锁花花芽;而开放花植株的叶片可溶性糖与淀粉含量均低于闭锁花植株叶片,说明开放花所需要的能量高于闭锁花,推测可溶性糖与淀粉含量的差异与两型花发育有一定的关系。     

The effect of day length,source of light and growth regulators on growth and flowering of Clerodendrum thomsonae Balf

The formation of flower buds in Clerodendrum seems not to be affected by day length, but the development of the buds is delayed in long days. When long days were established by means of low-intensity illumination with incandescent lamps, few flowers developed and the stems elongated considerably even at a day length of 16 hours. When fluorescent lamps were used for day-length extension, short shoots with many flowers were obtained even in 24-hour days. Flower development was also delayed by gibberellic acid (GA₃), but promoted by chlormequat both in short and long days. Shoot elongation was retarded by chlormequat and promoted by GA₃.Plants obtained from commercial greenhouses varied considerably with respect to growth and flowering. By selection a clone was obtained which flowered richly on short shoots. Shoot elongation stopped when flowering began. A ‘negative’ selection gave rise to a clone which flowered sparsely and in which shoot elongation was not influenced by flowering.     

Characterization of bud-burst potential in Rhododendron catawbiense ‘Album’ plants from in vitro culture by measuring the manganese contents in the distal buds

Summary

It had been established that photoperiodic conditions influence morphogenesis in Rhododendron catawbiense ‘Album’ (Ericaceae). Plants developed from cuttings obtained by in vitro culture were grown in a greenhouse for one or two years, under different photoperiodic treatments. Under long days, the upper buds followed a rhythmic development. Under short days, the inhibition of the growth of the distal buds allowed the development of shoots from the plant base. When plants were placed under long days after six weeks under short days, the distal buds recovered their capacity to form a new growth unit. To find a method to characterize growth potential of vegetative buds, measurements of their mineral content were made. A relationship between the changes in manganese level of the distal buds and their growth potential during the formation of the vegetative system has been established. Under short-day conditions, manganese increased to reach more than 500 mg kg^-1 dry matter in several weeks. Under long days, the manganese level in the upper buds gradually decreased before burst. These results may not provide an explanation for the role of manganese in relation to the buds physiological activity. On the other hand, manganese measurements may be a useful test to estimate growth potential in Rhododendron buds.     

The Cause of Black Blotch Disease of the Raspberry

Summary

Actively growing, single-stemmed plants of three black currant cultivars, each with 15 – 16 nodes, were exposed to photoperiods of 10, 14, 15, 16, 17, 18, 20, and 24 h at 18°C for 8 weeks for determination of the critical photoperiods for growth cessation and floral initiation. In all three cultivars, growth cessation was induced by short day (SD) conditions, with a critical photoperiod of 16 h, and the response was advanced by decreasing the photoperiod. The critical photoperiod for 50% flowering was 16 h in the cultivars ‘Öjebyn’ and ‘Ben Tron’, and 17 h in ‘Kristin’. Unexpectedly, however, not all plants flowered after exposure to a 10 h photoperiod, and the number of flowers per plant increased several-fold as the photoperiod was increased from 10 h to 15 h in all cultivars. Apparently, this unexpected result was due to the fact that all plants had only 15 – 16 nodes at the start of the experiments, which is marginal for “ripeness to flower” in black currant. While growth cessation was almost immediate in a 10 h photoperiod, causing only a few additional leaves to be formed during the experiment, the slower response to longer photoperiods apparently enabled the plants to reach the critical size at an earlier stage of the treatment period. However, although plants with 15 – 16 nodes were only marginally responsive to SD induction, buds situated as far down the shoot as the fifth or sixth node were competent to flower. It is therefore suggested that the inability of small black currant plants to flower resides in limitations of the leaves to respond to SD and to produce a florigenic signal, while their buds are fully competent to respond to such a signal.     

光周期对秋菊品种‘神马’花芽分化和开花的影响

 研究了不同光周期处理下秋菊‘神马’花芽分化的进程和生长开花状况。扫描电镜等结果表明, 花序由顶端生长点分化而成, 分为未分化期, 花芽分化起始期, 总苞鳞片分化初期及终期, 小花原基分化初期及终期, 花冠形成初期、中期和后期9个时期。分化顺序是向心的, 由外而内。雌雄蕊的发育与小花花冠分化同时进行。分化进程历时23 d, 其中花序分化与小花分化相比, 历时相对较长。短日处理植株花芽分化和花发育进程整齐均一, 生长正常; 短日加长日处理花芽分化无规律, 开花延迟, 产生畸形花;长日处理不能诱导开花。     

气温,光照条件对夏菊花品种花序芽发育的影响

夏菊花品种完成低温诱导后的进一步发育要求短日照条件；发育速度（以到成蕾、开花所需的天数表示）与气温呈负相关关系（相关系数分别为－０．９７和－０．９６），低光照强度不能逆转已分化的花序芽，但能延缓发育的速度和使顶花序芽下部各级侧芽发育成为营养簇生枝。     

‘地平线’天竺葵的花芽分化及光周期特性

 为了研究‘地平线’天竺葵的花芽分化特性及光周期对其生长发育的影响,采用石蜡切片 方法观察了花芽分化的过程,探讨了7 种光周期处理对始花期及开花质量的影响。结果表明：（1）‘地平 线’的花芽分化过程可以划分为8 个时期,持续时间大约为9 周;（2）‘地平线’花芽分化时期与各生长 指标（株高、株幅、真叶数和播种周数）均极显著相关,通过回归方程判断其幼龄期在5 片真叶前结束; （3）‘地平线’为量性短日照植物,促其早花的最佳光周期为昼12 h/夜12 h;（4）较长日照下‘地平线’ 的株形高大松散,较短光周期下矮小紧凑。‘地平线’天竺葵在5 片真叶前,采用16 h 日照栽培,可得到 健壮幼苗;5 叶期后,12 h 日照诱导,可促进分枝开花。     

‘三月红’荔枝不同温度处理的成花效应

利用控温室研究‘三月红’荔枝(Litchi chinensis Sonn.)成花诱导期和形态分化期不同的温度对成花的影响。结果表明,诱导期较低温(15℃/8℃,昼12h/夜12h),或者中度低温(18℃/13℃)处理,转移到高温(28℃/23℃)条件下,植株成花枝率低,而且也减少了每穗花的小花数和雌花质量。诱导期18℃/13℃,形态分化期15℃/8℃有利于成花。与18℃/13℃和15℃/8℃下发育的花芽相比,28℃/23℃下发育的花芽玉米素(ZRs)含量较低,而生长素(IAA)含量较高。高温处理下花芽中荔枝LEAFY同源基因(LcLFY)表达明显弱于低温处理。对不同温度下的成花与激素,以及与LcLFY表达的关系进行了分析讨论。     

以阶段观剖视荔枝的花芽分化

以阶段观剖视荔枝的花芽分化,重新审视了相关研究资料,对影响成花的关键因子作了阐释,廓清了一些概念性问题。引进了俗称的“白点”(拟改称“白小米粒”)作为“成花诱导期”和“花穗发端发育期”的分界标识。指出水分胁迫对于秋梢的停止生长和成熟是必需的,但对于花诱导本身则非所必需,因为尚无证据可证明干旱能够代替荔枝的低温成花诱导。荔枝成花诱导期需要低温,而花穗发端发育期则需要适度升温和水分。低温的成花诱导的效果不会被随后的水分增多所逆转。茎端感受诱导性低温时处于非细胞分裂的“静止”状态,而“白小米粒”的出现标志着茎端进入了细胞分裂的活跃状态。充分成熟的秋梢接受成花诱导的效果最佳,但未充分成熟的秋梢上处于“静止”状态的芽也可以感受诱导性低温,只是抽发的带叶花穗率往往较高。花穗发端发育期气温过高会导致花穗上叶原基的进一步发育成叶片和花序原基的萎缩,即俗称的“冲梢”。若诱导期经受的低温不足,则此情况会更甚。     

Flowering performance and yield of established and recent strawberry cultivars (Fragaria × ananassa) as affected by raising temperature and photoperiod

Plants of six strawberry cultivars were raised under controlled conditions and tested for flowering and yield potential. Short days (SD) at intermediate temperatures for 4 weeks in August induced profuse flowering in subsequent long days (LD) in all cultivars except the late-flowering ‘Malwina’. LD conditions induced flowering only in ‘Nobel’, which has an everbearing parent. ‘Nobel’ and ‘Saga’ exhibited broad temperature adaptation for SD floral induction, which was generally reduced or suppressed at 9 and 27°C. After autumn planting, all cultivars flowered most abundantly in plants raised in SD and intermediate temperatures. Flowering was earliest in ‘Nobel’ and ‘Rumba’. Plants that did not reach floral commitment after 4 weeks in SD continued and completed induction under subsequent natural SD conditions after planting in the field, demonstrating the capability of fractional induction. Berry yield varied in parallel with flowering in the field and was always higher in plants raised under SD conditions. The traditional cultivars ‘Florence’ and ‘Sonata’ out-yielded the more recent cultivars. Some cultivars lost more than two thirds of their initiated flowers during the winter with obvious consequences for their yields. With proper raising management, acceptable yields were obtained after autumn planting even in a cool Nordic climate.     

Plant growth regulators and flowering of Brunonia and Calandrinia sp.

Brunonia australis R. Br (Goodeniaceae) and Calandrinia (Portulacaceae), native to Australia, are potential new flowering potted plants. This research investigated the role of daylength and growth regulators, Gibberellic acid (GA₃) and paclobutrazol (Pac), to control vegetative growth, peduncle elongation and flowering of Brunonia and Calandrinia. Plants were grown under long days (16 h), short days (11 h) and 8 weeks under short day then transferred to long day (SDLDs). Plants in each daylength were treated with GA₃, Pac, and GA₃+ Pac. GA₃ was applied as 10 μL drop of 500 mg L⁻¹ concentration to the newest mature leaf. A single application of Pac was applied as a soil drench at 0.25 mg a.i. dose per plant. Both Brunonia and Calandrinia flowered earlier in long days but still flowered in short days, so both can be classified as facultative LD plants. Brunonia under SDLDs were more vigorous and attractive than plants under LDs while still being more compact than plants under SDs. In Brunonia, GA₃ promoted earlier flowering and increased the number of inflorescences under SDs. Pac at 0.25 mg a.i. per plant applied alone or in combination with GA₃ had extended flower development in Brunonia, and resulted in a reduced number of inflorescences per plant compared to the control plants. Vegetative growth of Calandrinia was similar under LDs, SDs and SDLDs, whereas GA₃ application increased plant size. Pac-treated Calandrinia looked compact and attractive, and Pac application did not affect time to flower and flower number.     

Synchronization of anthesis and enhancement of vegetative growth in coffee (Coffea arabica L.) following water stress during floral initiation

SUMMARY

The possibility of using water stress during floral initiation and development, to synchronize flowering in potted coffee trees of cvs Catuai Rojo and Mundo Novo was investigated. Moderate and severe cyclic and constant water stress had little effect on vegetative growth during floral initiation. However, upon rewatering, shoot growth was significantly greater in plants where leaf water potential [¨,] had declined to -2.5 MPa compared with plants where ¨, was maintained above -0.5 MPa. The period of floral initiation was not influenced by water stress and occurred only under short days (<12 h). In contrast, a y, of -2.5 MPa significantly reduced the number of inflorescences compared with plants maintained at a ¨| of -0.5 or -1.5 MPa. This reduction was associated with leaf drop in stressed plants. Therefore, regular irrigation during the period of floral initiation is recommended. Water stress (¨, of -1.5 or -2.5 MPa compared with -0.5 MPa) accelerated floral development with no deleterious effects on floral differentiation. Once flower buds are fully differentiated they enter dormancy and reach anthesis only if trees are stressed and rewa-tered. Flower buds remain dormant if trees are watered regularly or a constant water stress provided. A constant period of water stress in the late stages of floral development after floral initiation is complete provides a means of increasing the proportion of fully differentiated dormant flower buds (mature buds). This could represent a practical method to achieve synchronized flowering in field conditions where there is irrigation and a reliable dry season in the late stages of floral development.     

Vernalization promotes flowering of a heat tolerant Calandrinia while long days replace vernalization for early flowering of Brunonia

The flowering responses of Brunonia australis (blue pincushion) and Calandrinia sp. to vernalization, photoperiod, temperature and plant age were investigated to provide a foundation for manipulating flowering in these potential potted plants. Plants were vernalized at 4.8 °C for 0, 3 or 6 weeks at the plant age of 1–4 or 8–14 leaves. Following vernalization, plants were grown at 25/10 or 35/20 °C (day/night) under short days (11 h, ambient daylight averaged 380 ± 44 μmol m⁻² s⁻¹) or long days (16 h) provided by an additional 5 h night break (21:00–2:00 h at <4.5 μmol m⁻² s⁻¹ from incandescent lamps), for 85 days. This is the first work to investigate flowering of these ornamental species. Both species showed enhanced flowering following vernalization and a quantitative requirement for long days. The reduction of the time until the first visible inflorescence (Brunonia) or flower (Calandrinia) buds by 8–13 days was affected by vernalization for 3 or 6 weeks, respectively. Long days were effective for reducing the time to first visible floral bud and increasing the number of inflorescence or flowers per plant for both species. For Brunonia, LDs replaced vernalization when applied to plants with 1–4 leaves. Raising temperature from 25/10 to 35/20 °C increased the number of flowers per plant of Calandrinia by 2–2.5-fold for plants with 1–4 or 8–14 leaves respectively.     

The effectof daylength and supplementary lighting on the growth of Begonia × hiemalis leaf cuttings

No consistent differences in growth were observed between leaf cuttings of Rieger begonia ‘Schwabenland Red’ taken from stock plants grown under different daylengths.The effects of supplementary illumination, daylength and polythene-covering treatments applied during the 5-week propagation period were also small. Leaf size did not affect the subsequent development of the cutting, but large leaves trimmed to a size comparable to the smaller leaves rooted poorly and produced few shoots.After rooting, the young plants were very responsive to daylength. Under long days growth was rapid, but under short days a large percentage of the plants failed to regenerate. When shoots did appear on these plants, they were few in number and flowered precociously.     

苹果SUPERMAN家族基因的组织特异表达及MdSUP3的功能分析

通过半定量RT-PCR分析SUPERMAN家族基因在‘富士’苹果（Malus × domestica Borkh.‘Fuji’）叶芽、幼叶、花芽、花蕾、花、皮部组织和幼果中的表达模式,通过MdSUP3自主启动子驱动的GUS基因表达和MdSUP3异位表达分析其功能。结果表明,MdSUP3、MdSUP11和MdSUP9a在所检测的组织器官中均有表达,MdSUP9b主要在营养器官中表达,MdSUP5a、MdSUP1b主要在生殖器官中表达。MdSUP3启动子驱动GUS基因在植株根尖、幼叶、幼茎和花等器官中表达。超表达MdSUP3的转基因烟草植株矮化、节间缩短、叶片卷缩、花器官颜色改变和部分花器官形态异常;与对照相比,转基因烟草中ABA合成酶基因NtNCED3-2,花青素合成途径的NtDFR2和NtANS1基因表达显著上升,细胞分裂素氧化酶基因NtCKX和赤霉素氧化酶基因NtGA2ox4表达显著下降。异位过量表达删除C端DLELRL基序的MdSUP3基因不影响转基因烟草的生长发育,证明DLELRL是基因必不可少的功能域。     

Molecular characterization of an S-adenosylmethionine decarboxylase gene from floral organ differentiating axillary bud in calamondin (× Citrofortunella mitis)

Summary

Calamondin (× Citrofortunella mitis J. Ingram & H. E. Moore) is known for its ability to develop floral organs to flower in the adult phase during the four seasons. To provide information on molecular events during floral differentiation from axillary buds, we constructed a cDNA library from floral differentiating axillary buds of adult phase calamondin. Ninety-six cDNA clones were randomly selected from this library and sequenced. Ninety-six nonredundant ESTs were identified. Two clones encoded S-adenosylmethione decarboxylase, a key enzymes in polyamine biosynthesis. CmSAMDC 1 (Citrofortunella mitis s-adenosylmethionine decarboxylase 1) contained an 1083 bp ORF that encoded a putative SAMDC precursor of 361 amino acids. Northern blot analysis revealed that CmSAMDC 1 was expressed in axillary buds prior to floral differentiation and in axillary buds immediately after floral differentiation, in immature flower (5 mm), in fully developed flowers (120 mm long), in floral parts (petals, pistils, and stamens) of trees in the adult phase of development, but not in leaves or axillary buds of juvenile phase nucellar seedlings or leaf tissue from trees in adult phase of development. In situ hybridization revealed expression of the CmSAMDC 1 gene in the floral apex of axillary buds after differentiation, and in the phloem of axillary buds and petioles. These results suggest that SAMDC could play a role in actively differentiating and developing reproductive and vegetative organs.     

沈阳地区天女木兰生物学特性研究

以沈阳地区栽培的天女木兰为研究对象,详细观察测定了该树种的物候期、芽萌发形态变化、开花习性以及枝、叶、果的生长动态等生物学特性。结果表明:天女木兰芽在4月上旬开始萌动,生长期约为150d,旺盛生长期从5月上旬到6月中旬,大约50d;5～6月枝、叶、果生长量最大,此期间新梢生长量占当年新梢总生长量(18.3cm)的81%;天女木兰具有"二次开花"现象,第1次开花(主花期)在5月下旬至6月中旬,持续约20～30d,第2次开花在7月末至8月初,花数量少,持续时间短;果实从生长到发育成熟约需90d,成熟期在9～10月。     

Possible role of non-structural carbohydrates in flower induction in strawberry

Summary

Flower-induction is the event that initiates the transition of a vegetative apex into a floral apex in response to an environmental or developmental cue. Under flower-inducing conditions, biochemical or physiological changes can be recognised. One possible change that could occur is in sugar content. In this study, levels of non-structural carbohydrates (e.g., sucrose, glucose, fructose and starch) were measured in shoot tips, leaves and roots of strawberry (Fragaria ananassa cv. ‘Kordestan’) under flower bud-inducing conditions, and compared with non-induced plants. Runner plants were potted and grown for 4 weeks under non-inducing conditions (31º/25°C day/night; 16 h daylength). Half of the plants were then put under flower-inducing conditions (25°/15°C day/night; 8 h daylength) for 3 weeks. Samples for carbohydrate analysis were taken from induced and non-induced plants every 3 d over 3 weeks, and sucrose, glucose and fructose contents were determined by HPLC, and starch concentrations by the anthrone method. The most abundant soluble sugar, in all organs tested, was sucrose. Sucrose levels in shoot tips and leaves decreased at the beginning of the induction treatment, but soon increased to the levels recorded in non-induced plants. Fructose increased markedly in shoot tips of induced plants 3 d after the start of the short-day treatment, and declined thereafter. Starch contents in shoot tips, leaves and roots of non-induced strawberry plants were higher than those in induced plants on most sampling dates. From the results of this study, it appears that soluble carbohydrate contents in different organs of June-bearing strawberry may have a decisive role on flower-bud induction.