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.     

Flowering of tomato in vivo and in vitro in relation to the original position of the axillary bud on the main axis

In vitro cultured tomato seedlings were micropropagated using the single-node method. By periodically subculturing single nodes and shoot tips in vitro, tomato progeny were obtained that arose from axillary buds (nodes) 1 (base) to 9 (top). Rooted shoots were transferred periodically to soil and were grown further in a greenhouse to observe flowering. The number of leaves preceding the first inflorescence in the various groups of plants was not influenced by the original position of the axillary buds on the main stem. Similar results were obtained in decapitation experiments in vivo. These results indicate that axillary buds on the main stem of tomato plants do not differ in their flowering behaviour.     

春化对白菜DNA 甲基化、GA含量及蛋白质的影响

 以普通白菜‘油冬儿’为试材, 研究了低温对白菜开花的诱导效应, 并分析了萌动种子和幼苗春化诱导后DNA 甲基化水平、赤霉素(GA) 含量和蛋白质种类的变化。结果表明, 不论萌动种子还是幼苗, 4 ℃低温处理30 d 均可完成春化。春化处理后, 两处理植株茎尖组织DNA 甲基化水平都较对照下降;但GA 含量明显上升, 为对照的2～3 倍; 低温诱导植株产生了一种分子量为58 kD 的特异蛋白质, 同时也使一种蛋白质消失。说明低温可能通过降低DNA 甲基化水平或增加GA 含量而诱导植物开花。     

Quantitative trait analysis of transplanting time and other root-growth-related traits in tomato

Transplanting time is determined by factors such as the field conditions, the age of the seedlings, and the size of the container, but little information is available on the effect of the genetic background on transplanting time. Here, we examined root dry weight (RDW), shoot dry weight, root/shoot ratio (RSR), time at which 50% of the germinated seedlings have expanded cotyledons (CE50), root ball formation (RBW), the length of time from the cotyledon expansion from the first to the last germinated seedling (ES) and transplanting time (TRD) in a BC₁F₆ population derived from Solanum lycopersicum and Solanum pimpinellifolium. All traits exhibited significant correlation with each other, except for RSR, which was only significantly correlated to RDW. A total of eight additive quantitative trait loci (QTLs) were detected for the five traits, i.e., RSR, RBW, CE50, ES, and TRD. One epistatic (QTL × QTL) interaction each was identified for RSR and TRD. QTLs for RSR, RBW, CE50, ES and TRD clustered near marker LEOH37 on chromosome 4. Clustering of ce50-4, rsr4, rbw4, and es4 with trd4 reflected the dependence of transplanting time on root ball formation, growth uniformity and early seedling growth, especially root growth. In addition, several QTLs in this study were mapped to regions where QTLs for days to flowering or number of leaves before the first inflorescence had been identified previously. This suggests that the roots may exert some influence on the flowering time in tomato.     

The effect of soil temperature on lateral shoot formation and flower-bud formation in apple in the first year after budding

Under controlled environment conditions the influence of four soil temperatures (7°, 14°, 21°, and 28°C) on vegetative development and flower-bud formation of apple trees (cvs ‘Rode Boskoop’ and ‘Elstar’) were evaluated in the first year after budding. Relative air humidity was high, air temperature was 20°C. Broadly speaking, for both cultivars shoot growth clearly increased with increasing soil temperature. The effects on growth were mainly reflected in the number (not length) of the lateral shoots; the growth of the main shoot was little influenced by soil temperature. At 7°C the lateral shoots usually occurred higher along the main stem than at the higher temperatures. Flowering on the parent stem and on the lateral shoots was little affected by the soil temperatures tested. In general, flower-cluster quality was rather poor. If only clusters having more than four well-developed flowers are considered, flowering was favoured by higher soil temperatures; at 28°C, especially, cluster quality was much better than at the other soil temperatures. It is concluded that soil temperature is important in controlling the degree of lateral shoot-formation as well as the formation of well-developed flower clusters.     

Flower initiation of chrysanthemum seedlings grown continuously in short days at four levels of irradiance

Chrysanthemum seedlings grown continuously under flower-inducing short-day conditions did not initiate flowers rapidly, but continued to produce leaves. A minimum leaf number seemed necessary before the seedlings responded to the relative length of day and night. The minimum leaf number varied with the initial size of the seedling, genotype and level of irradiance. When growing seedlings — or juvenile cuttings — for the purpose of selecting plants for vegetative propagation, the minimum leaf number required for flowering should be met before the start of the short-day period.     

Studies on the induction of flowering in juvenile Prunus avium L.

Juvenile Prunus avium shoot apices produced flowering shoots after grafting to mature trees irrespective of treatment of the apices in the season before grafting with G A or G A + cytokinin. Scions grown from mature shoot apices grafted to seedling stocks failed to flower, again irrespective of prior hormone treatment. Similar treatment of mature shoot apices with these hormones, or with zeatin, inhibited concurrent floral initiation, but G A or GA + zeatin treatments increased flowering of scions grown from the treated apices after grafting to untreated mature trees. Localized shoot tip or root drench treatment of one or two year old seedlings with (2RS, 3RS)-paclobutrazol failed to induce flowering, but treatment of three or four year old plants did stimulate flowering. Branch or stem girdling or root flooding applied alone or in combination to three year old plants did not affect flowering. Floral initiation by three or four year old plants was inhibited by treatment with GAs. The results were consistent with the presence in seedlings of a root- produced, xylem transported, graft-transmissible inhibitor(s), which control the initiation of otherwise competent meristems, and which could include factors other than GAs. Juvenile meristem competence to flower was not affected by prior GA treatment.     

Prolonged high-temperature exposure differentially reduces growth and flowering of 12 Viola × wittrockiana Gams. cvs

Many cool season garden crops, including Viola × wittrockiana Gams. (pansy), exhibit reduced flowering outdoors during the warm summer months. Twelve pansy cultivars varying in summer garden performance were grown under either 20 ± 1.5 or 30 ± 1 °C (air temperature) to determine growth and flowering responses to prolonged high-temperature exposure and to identify selection criteria to screen pansies for flowering heat tolerance. Increasing temperature from 20 to 30 °C increased leaf number below the first flower on ‘Crystal Bowl Primrose’ and ‘Skyline White’ only. Flower bud number reduction at 30 °C versus 20 °C varied from 20% for ‘Crystal Bowl Purple’ to 77% for ‘Majestic Giants Red and Yellow’. Flower diameter reduction at 30 °C versus 20 °C ranged from 14% for ‘Skyline Beaconsfield’ to 44% for ‘Super Majestic Giants Ocean’. The percentage reduction in total color (flower number × estimated flower area) ranged from 60% for ‘Crystal Bowl Primrose’ to 88% for ‘Majestic Giants Rose Shades’. Based on a weighted base selection index, ‘Super Majestic Giants Canary’ and ‘Delta Yellow’ were identified as the most heat-tolerant cultivars, while ‘Super Majestic Giants Ocean’ and ‘Majestic Giants Rose Shades’ were identified as the most heat-sensitive. In a second experiment, root and shoot dry mass were determined after 10, 20, or 30 d when grown at 20 or 30 °C. Relative growth rate and root:shoot ratio were also calculated. After 30 d, ‘Crystal Bowl Primrose’, ‘Crystal Bowl Sky Blue’ and ‘Skyline White’ relative growth rates were lower at 30 °C versus 20 °C. Root:shoot ratio on day 30 was lower at 30 °C compared to 20 °C for six cultivars, but similar across temperature for five cultivars and higher for ‘Crystal Bowl Primrose’. Flower bud number at first flower was positively correlated with branch number, shoot dry mass at flowering, but not correlated with root dry mass at flowering, and negatively correlated with flower diameter and root:shoot ratio (either at flowering, or after 10, 20 or 30 d at 30 °C), suggesting that these traits may be useful when screening pansies for flowering heat tolerance.     

Shade Effects on Growth and Development of Cacao Following Two Years of Continuous Dry Season Irrigation

ABSTRACT

The deployment of plantain shade and irrigation (5- and 10-day) intervals) for enhancing survival, field establishment, flowering and pod production of field-grown cacao seedlings in the dry season was investigated. The effects of dry season irrigation was profound on cacao growth, field establishment (over 90% seedling survival) and development, flowering and pod production. For the non-irrigated moderately shaded cacao, about 30% of the transplanted seedlings survived and the achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. Open sun in combination with 5-day irrigation interval had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. Lower values of air and soil temperatures were obtained for combination of irrigation and shade regimes (dense and moderate) and higher soil moisture contents. The shade-irrigation combinations ameliorated microclimate and enhanced growth and development, seedling survival, root and shoot development, advanced flowering and promoted uniform fruiting/pod production and total bean yield. The effects of dry season irrigation at 5- or 10-day intervals was profound on cacao growth, field establishment (over 90% seedling survival), flowering and pod production. Irrigated unshaded (open sun) cacao had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. The achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. The drip irrigation strategy adopted ameliorated dry season terminal drought (hydrothermal stresses) and promoted cacao growth, survival and flower/pod production.     

Flower-bud formation in apple under various day and night temperature-regimes

Starting at full bloom, 4 temperature treatments were applied to 3-year-old ‘Golden Delicious’ and ‘Cox's Orange Pippin’ trees. Either 17 or 24° C were applied in 3 successive periods of 5–6 weeks each.In ‘Golden Delicious’, exposure to 24° C during the first 5 weeks after full bloom enhanced shoot growth and reduced flower-bud formation in spur buds. The difference in temperature-regime during the third period did not affect either growth or flowering. Almost all apical shoot buds became floral, irrespective of treatment.‘Cox's Orange Pippin’ trees maintained at 24° C throughout grew more vigorously than did those kept at 17° C continuously, but flowering-abundancy was the same. Lowering of the temperature in the last period before harvest did not influence shoot growth, but markedly reduced flowering of both spur buds and apical shoot buds.In a second experiment, a night temperature of either 20 or 10° C was applied in 2 successive periods to 3-year-old ‘Cox's Orange Pippin’ trees kept at a day temperature of 20° C throughout. Lowering of the night temperature in the middle of the season reduced flower-bud production, but there was no difference in growth vigour compared with 20° C continuously.It is postulated that temperature affects flowering in two opposite ways, whose relative importance determines the net result.     

Phenology of strawberry guava (Psidium cattleianum) in ReÂunion Island

Summary

The phenology of wild stands of strawberry guava (Psidium cattleianum Sabine) was studied at 100, 480 and 720.m over 2 years in ReÂunion Island. The shoots bore flower buds at the basal nodes, and vegetative buds at the apical nodes. Trees produced vegetative growth from September to December, flowers from November to January and fruit from February to June. Shoot growth was earlier at 100 and 720.m the first year, but were synchronized in the second year. Flowering and fruiting were also earlier at 100.m. The intervals between shoot emergence and flowering, and flowering and fruit maturity were strongly related to temperature, with base temperatures of 5.58C and 2.68C, and heat units requirements of 675 and 2,5528C.d, respectively. The number of shoots, flowers and fruit per branch varied across sites and years, unrelated to temperature. However, production was significantly higher at 720.m. Production was much lower after a hurricane. Flowering (y) was related to shoot production per branch (x) (log(y)=111.33.log(x); r².=.0.78), whereas the fruit set rate was highly variable between trees (26±100%). The number of fruits per branch (1±6) was possibly related to poor shoot growth or fruit set, but unrelated to the timing of the phenological events. It is expected that commercial orchards would be more productive than feral stands.     

Citrus hybrid seedlings reduce initial time to flower when grafted onto shiikuwasha rootstock

The long juvenile period of citrus seedlings before flowering is one of the major obstacles in citrus breeding. Under the citrus breeding program of National Institute of Fruit Tree Science in Japan, 299 citrus hybrid seedlings were grafted onto shiikuwasha (Citrus depressa HAYATA) and cultivated. Approximately one-third of the plants flowered two and a half years after grafting. The average length of the main stems of flowering plants was 308 cm, while that of non-flowering plants was 264 cm. Half of the plants having main stem length ≥300 cm formed flowers, while most of the plants having main stem length <210 cm formed no flower. These results indicate that plant vigor influences the flowering and that grafting effectively accelerated flowering. The proportion of flowering plants varied among cross combinations, ranging from 71.4% to 8.0% among the 10 cross combinations used.     

Interaction of temperature and light on growth and development of hybrid tea-rose seedlings,with reference to breeding for low-energy requirements

As a basis for a breeding-programme of glasshouse roses adapted to low-energy conditions (low temperature and low light intensity), growth and development of Hybrid Tearose seedlings were studied in 9 controlled environments (16, 20 or 24°C combined with 8, 16 or 24 Wm^?2 for 8 h). The percentage of flowering seedlings increased with increasing light intensity independent of temperature, rapidity of flowering was promoted by increasing both light intensity and temperature, stem length at anthesis was promoted by increasing light intensity but shortened by increasing temperature. The possibility of selecting seedlings, and consequently cultivars, adapted to low-energy conditions was discussed.     

Responses of Alstroemeria ‘Regina’ to temperature treatments prior to flower-inducing temperatures

Days to flower (DTF) were inversely related to the number of weeks (0–8) that Alstroemeria ‘Regina’ plants remained at 5°C, a vernalizing temperature, before being moved to 13°C, a vernalizing as well as a forcing temperature. However, when the number of weeks at 5°C was added to the DTF, no difference in the total time to flower was observed between plants treated at 5°C or those grown continuously at 13°C, as they both induced flowering. One-year-old plants maintained at 21°C, a non-inductive temperature, and not divided prior to the 5°C treatments, showed an increase in total shoot production, and delayed DTF, compared to plants which were divided. When divided plants were maintained for 16 weeks at 21°C prior to 5°C treatments, total shoot production was reduced but flowering was accelerated compared to plants maintained for 8 weeks at 21°C after dividing. Total shoot and flowering-shoot production was not affected by increasing the durations of time at 5°C when plants were grown at 21°C and divided prior to this treatment. Thus, the pre-treatment of dividing or maintaining plants at 21°C prior to a 5°C treatment affected subsequent shoot production and DTF.     

Olive seedling first-flowering position and management

The prolonged length of the juvenile period represents a substantial obstacle in olive (Olea europaea) breeding programs, delaying both the possibility for analyzing the fruit, the harvest unit, and the capacity for sexual recombination. In both olive and other fruit tree species, the juvenile–adult transition has been successfully hastened by forcing and formation procedures designed to rapidly achieve a minimum height. Precise knowledge of the position within the tree canopy where the juvenile–adult transition occurs, identified by the location of the first flowers, offers further potential for manipulating tree structure in order to hasten that transition. The occurrence of the juvenile–adult transition has been described spatially within the canopy as the formation of a juvenility cone, which we report here for olive plants from seed, and for the first time quantitatively describe its position based on the added trunk and branch distances from the soil. In canopies of seedlings from open pollination of cv. Arbequina olive the first-flowering position was consistently located, in our conditions, at an average distance of 200 cm from the trunk base. Based on that evidence, that first flowering can occur at lower positions, and on the values we obtained, three canopy-formation heights (100–130 cm, 130–160 cm and >160 cm) were compared for their effect on the length of the juvenile period and the vigour of olive seedlings. Canopy heights of 100–130 cm, much lower than the 160 cm previously reported by the olive tree breeding program of Córdoba, produced the highest number of flowering plants in the first two flowering years and also provided easier management.     

Deferring flowering of nobile dendrobium hybrids by holding plants under low temperature after vernalization

Orchids are currently the most valuable potted crop in the United States. To date, no studies focused on making possible the year-round greenhouse production of flowering nobile dendrobium orchids. This experiment was aimed at developing a strategy to defer flowering of nobile dendrobium orchids by holding them under low temperature. Mature Den. Red Emperor ‘Prince’ and Den. Sea Mary ‘Snow King’ were held at 10 °C for various durations (0, 4, 8, 12 or 16 weeks) after vernalization (4 weeks at 10 °C). Plants were forced in a greenhouse after holding. Time to flower, flower differentiation (flowering node percentage, number of aerial shoot and aborted bud) and flower quality (total flower number, flower diameter, flower number per flowering node and flower longevity) were determined. Increase of low temperature holding duration from 0 to 16 weeks extended time to flower up to 3 months and did not affect parameters of flower except producing larger flowers and reducing flower number per flowering node for Den. Red Emperor ‘Prince’. Notably, the flower longevity was not adversely affected. Defoliation was aggravated in Den. Red Emperor ‘Prince’ by longer duration of cooling and was considered a detrimental effect of low temperature holding.     

利用柠条粉发酵料作为育苗基质对甜瓜幼苗质量的影响

以柠条粉发酵料为原料作为育苗基质,以现有育苗基质为对照,通过幼苗生长发育、干物质积累等指标,比较分析柠条粉基质育苗效果。结果表明:柠条粉基质幼苗株高、茎粗、根长、叶片数、地上部鲜质量、地下部鲜质量、全株鲜质量、地上部干质量、地下部干质量、全株干质量和根冠比等生长发育指标与壮苗二号基质幼苗趋于一致,且在出苗后30 d时,柠条粉基质幼苗壮苗指数高于壮苗二号基质幼苗壮苗指数12.12%,该试验结果为柠条粉基质应用及新基质开发提供了参考。     

春化和赤霉素对大白菜抽薹开花的影响

在温室补充光照条件下,研究了低温春化时间和ＧＡ３浓度处理对早熟和晚熟大白菜生长开花的影响。结果表明,随着春化时间的延长,从播种到开花的时间缩短,叶片数减少,株高增加。ＧＡ３处理也随着浓度的提高表现出与低温春化处理相似的结果。在大白菜加代繁殖中,春化处理１５ｄ（天）,然后用３００ｍｇ·Ｌ－１ＧＡ３处理幼苗是促进大白菜抽薹开花的最佳因素组合。     

苹果杂种后代亲本性状遗传倾向的研究

通过对20个苹果杂交组合的587侏后代本性状的遗传倾向的研究看出,在河南郑州地区,苹果杂种的童期一般为5年,6年生苹果杂种实生苗一般开花株率为25％,7年生可达50％以上;童期的长短主要受亲本的制约;干周15cm为杂种植株童期即将结束或已结束的标志。苹果杂种初次开花结果的部位主要为短果枝,约占60％,大多数杂种具有腋花芽结果习性。苹果杂种的果实一般均小于亲中值,平均较亲中值小38.5％。色泽的遗传表现为红对黄为显性,但在红×红的后代中有相当比例的绿黄果。果实的风味遗传相当复杂,但无论甜×酸或甜×甜,后代中果实风味酸甜的所占比重最大,并且甜×甜的后代中可出现甜的类型。富士和金冠是培育优质新品种的最好亲本;新红星的红色遗传传递力似乎较强。     

中国野生葡萄副梢长度的RAPD标记

为培育短副梢葡萄品种,对中国野生葡萄副梢长度性状进行调查,以葡萄短梢×长梢的葡萄种间杂交组合(燕山-1×河岸葡萄)F183个单株为试材,采用BSA法和RAPD技术,通过369个随机引物的筛选,获得了1个与中国野生葡萄副梢长度基因连锁的RAPD标记OPB07-2000,并在中国野生葡萄17个种46个株系中得到验证。这就为葡萄短副梢分子辅助育种提供了科学依据,进而从根本上解决葡萄生产上夏季副梢生长过旺的问题。