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《Scientia Horticulturae》2005,106(2):203-212
Cultivation of roses in various soil-less media was studied with the aim to identify the optimum soil condition for rose production. Madelon roses grafted on rootstock of Rosa indica var. major were transplanted to polyethylene bags containing zeolite and perlite (at ratios of 25z:75p, 50z:50p, 75z:25p and 100z:0p, v/v) in a climate-controlled greenhouse. Net photosynthesis (Anet), stomatal conductance (gs) and water use efficiency (WUE) of roses were followed for 5 months. Flower production and quality were recorded in three flowering flushes during a 5-month period. Analysis of variance of repeated measurements showed that even though the overall Anet did not differ among treatments (average 18.7 μmol m−2 s−1), trends in Anet seasonality for roses in 25z:75p substrate differed significantly from those in 50z:50p, 75z:25p or 100z:0p. Stomatal conductance did not show any significant seasonality or trends in response to substrate mixtures, averaging 0.89 mol m−2 s−1. Water use efficiency was significantly lower for roses in 25z:75p than in 100z:0p mixtures (1.8 ± 0.15 and 2.0 ± 0.13 μmol m−2 s−1 CO2/mmol m−2 s−1 H2O, respectively). Cumulative production of rose plants did not differ among substrate mixtures. Productivity significantly differed among flower stem classes. Stem class I (>70 cm) and class V (≤30 cm) exhibited the least production, contributing to only 7.6 and 3.7% of the total production, respectively. The highest productivity was observed in classes III (51–60 cm) and IV (31–50 cm), contributing to the bulk of productivity (68.4%). Class II contributed a 20.3% of the production. Results showed that zeolite and perlite acted as inert materials. Zeolite did not exert any positive effect on productivity, in contrast to what has been reported in literature recently. Use of perlite resulted in a little improvement in photosynthesis, however this improvement was not reflected by a significant increase in production. 相似文献
3.
In an effort to increase the accessibility and functionality of shallow green roof systems, the ability of warm-season grasses to provide acceptable growth needs to be further investigated. In the current study, which was conducted during 2011 and 2012, three warm-season grasses (hybrid bermudagrass, Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy ‘MiniVerde’; seashore paspalum, Paspalum vaginatum Swartz ‘Platinum TE’ and zoysiagrass, Zoysia japonica Steud. ‘Zenith’) were established in outdoor lysimeters. The lysimeters were equipped with all necessary green roof layers placed below a coarse-textured substrate that comprised pumice, thermally treated attapulgite clay, peat, compost and zeolite. Half of the lysimeters had a substrate depth of 15 cm, while the other half had a substrate depth of 7.5 cm. Irrigation was applied at crop evapotranspiration (ETc). Measurements included determination of substrate moisture content, green turf cover (GTC) and leaf stomatal resistance. Significant differences were observed in the values of GTC among the three turfgrass species and the two substrate depths. Zoysiagrass exhibited the best adaptation at the lower depths of shallow green roof systems. At 15 cm substrate depth, zoysiagrass managed to sustain green coverage for the two study periods. In addition, it was the only turfgrass species that managed to perform well at the substrate depth of 7.5 cm. Seashore paspalum exhibited limited green cover at both substrate depths, while hybrid bermudagrass could provide acceptable green coverage only at 15 cm substrate depth. 相似文献
4.
《Scientia Horticulturae》2005,106(4):464-471
This research was carried out to assess the effects of zeolite and perlite on growth and nutrient status of lettuce plants and the amount of waste elements. The trials were done in a PE covered tunnel during autumn and spring seasons. Plant material was Lactuca sativa var. capitata, and the cultivars Bombola and Brogan were used for autumn and spring seasons, respectively. Five different growing media based on perlite and clinoptilolite, a kind of zeolite, mixed at different ratios (1 + 0, 3 + 1, 1 + 1, 1 + 3, 0 + 1, v/v) were tested. It was concluded that the use of zeolite led to increased plant growth, higher N and K contents in plant tissues and to reduced K leaching. 相似文献
5.
Dwarf geophytes have great potential for use on extensive green roofs because they often come from arid areas and can survive dry and hot summer in a dormant state. However, there has been little research regarding geophytes on green roofs. This experiment was conducted to study the performance of 26 species of geophytes on a green roof during 2005–2006 in Sheffield, UK. The geophytes were grown at two substrate depths (5 cm and 10 cm) of substrate on a green roof without irrigation. To investigate the susceptibility of geophytes to competition from a covering of permanent plants, the geophytes were grown with or without a surface vegetation layer of Sedum album. Overall, the growth, survival rate, regeneration and flowering of geophytes were more successful at a substrate depth of 10 cm than of 5 cm, probably because of improved moisture retention, fewer temperature fluctuations and the protection from digging by animals. The flowering period was limited to spring, therefore, it is recommended to combine with other plant species such as covering plants. Geophyte species did not compete much with S. album and Sedum cover had no significant effects on the growth, survival rate, regeneration and flowering of geophytes in most species. Iris bucharica, Muscari azureum, Tulipa clusiana var. chrysantha, Tulipa humilis, Tulipa tarda and Tulipa turkestanica had good performance at the substrate depth of 5 cm. In addition, Narcissus cyclamineus ‘February gold’ and Tulipa urumiensis exhibited a successful performance at the substrate depth of 10 cm. 相似文献
6.
On the Cornell University campus a long-term study has measured the impacts of a soil remediation strategy on plant growth and soil quality using the Cornell Soil Health Test. The Scoop & Dump (S&D) process of soil remediation consists of physically fracturing compacted urban soils, incorporating large quantities (33% by volume) of compost with the use of a backhoe, and annually top dressing with mulch. This study was designed to investigate the impact of this remediation technique for the amelioration of compaction and degradation of soils in the urbanized environment.The study finds that over a 12-year period remediated soils exhibit improved (reduced) bulk density (R2 = 0.50) (P < .0001) (n = 30), increased active carbon (R2 = 0.61) (P < .0001) (n = 30) and increased potentially mineralizable nitrogen (R2 = 0.61) (P < .0001) (n = 30). When S&D soils were compared to unamended (Unam) soils, improvements were found in aggregate stability (S&D = 72.41%, Unam = 34.90%, P < .0001, n = 30), available water holding capacity (S&D = 0.22%, Unam = 0.15%, P < .0001, n = 30), total organic matter (S&D = 8.43%, Unam = 3.23%, P < .0001, n = 30), potentially mineralizable nitrogen (S&D = 27.53 mg/kg, Unam = 3.11 mg/kg, P = 0.0005, n = 30), active carbon (S&D = 1022.47 mg/kg, Unam = 361.60 mg/kg, P < .0001, n = 30), and reduction in bulk density (S&D = 0.89 g/cm3, Unam = 1.47 g/cm3, P < .0001, n = 30). Application of the S&D process provides an alternative to using specified soils and has potential for improving long term soil quality using locally sourced materials and simple methods. 相似文献
7.
《Scientia Horticulturae》2005,104(1):25-36
We studied the effects of Fe deficiency on physiological parameters of citrus rootstocks grown in nutrient solution. Three 4-week old rootstocks (‘Troyer’ citrange – Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf., Citrus taiwanica Tan. and Shim., and ‘Swingle’ citrumelo – Poncirus trifoliata (L.) Raf. × Citrus paradisi Macf.) were grown in nutrient solutions with 0, 5, 10, 15 and 20 μmol Fe dm−3. Calcium carbonate (1 g dm−3) was added to all solutions to mimic the natural conditions in calcareous soils. For each rootstock, shoot length, number of leaves, and root and shoot dry weights were measured at the end of experiment. Chlorophyll concentration was estimated using a portable SPAD-502 meter calibrated for each rootstock. The amount of nutrients (P, K, Mg, Ca, Fe, Zn, Mn, and Cu) was determined in shoots. Chlorophyll fluorescence parameters (F0: basal fluorescence; Fm: maximum fluorescence; Fv = Fm − F0: variable fluorescence) were measured with a portable fluorimeter. ‘Troyer’ citrange rootstock was the most tolerant to Fe deficiency. These plants grew more and accumulated more chlorophyll and nutrients than the others in the presence of low levels of Fe (10 μmol Fe dm−3). ‘Swingle’ citrumelo plants needed 20 μmol Fe dm−3 in the nutrient solution to secure adequate growth. ‘Taiwanica’ orange rootstock had an intermediate behaviour, but could be distinguished from ‘Troyer’ citrange based on fluorescence parameters, since there was a variation in the basal fluorescence in the former, whereas in ‘Troyer’ citrange the basal fluorescence was not affected by the supply of Fe. 相似文献
8.
《Scientia Horticulturae》2005,105(2):197-211
CO2 concentration was monitored during three 15-day subculturing cycles in vessels containing actively proliferating plum cultures of Prunus cerasifera, clone Mr.S. 2/5. The effects of two photosynthetic photon flux density regimes: 50 ± 5 μmol m−2 s−1 and 210 ± 5 μmol m−2 s−1 were compared. Three distinct phases in the CO2 trend were distinguished during each culturing cycle of both light treatments. In the first, occurring at the beginning of the culture cycle, the amount of CO2 emitted by the cultures during dark periods was greater than that assimilated during the light periods. In the second phase, the opposite trend was detected, while in the third, the range of CO2 day–night fluctuations increased or remained stable according to the number of explants per vessel. The treatment with 210 ± 5 μmol m−2 s−1 did not modify the CO2 phase trend but induced more pronounced fluctuations in day–night CO2 concentration. Under this light treatment, cultures reached CO2 compensation point for a period as long as 48% of the total number of light hours, while under 50 ± 5 μmol m−2 s−1, it was only 8%. The different range in CO2 day–night fluctuations monitored throughout a subculturing cycle, appeared to be mainly induced by changes in culture growth dynamics. 相似文献
9.
The implementation of trees in urban environments can mitigate outdoor thermal stress. Growing global urban population and the risk of heatwaves, compounded by development driven urban warmth (the urban heat island), means more people are at risk of heat stress in our cities. Effective planning of urban environments must minimise heat-health risks through a variety of active and passive design measures at an affordable cost. Using the Solar and Longwave Environmental Irradiance Geometry (SOLWEIG) model and working within the bounds of current urban design, this study aimed to quantify changes in mean radiant temperature (Tmrt) from increased tree cover at five different 200 × 200 m urban forms (including compact mid-rise development, residential and open grassy areas) within a suburb of Adelaide, Australia during summer. Following a successful validation of SOLWEIG, street trees were strategically distributed throughout each of the five urban forms and the model run over five warm sunny days (13–17 February 2011). Results showed spatially averaged daytime (7:30–20:00) Tmrt reduced by between 1.7 °C and 5.1 °C at each site, while under peak heating conditions (16 February, 14:00) Tmrt reduced by between 2.0 °C and 7.1 °C. The largest reduction in Tmrt under peak warming conditions was at the residential site, despite having the fewest number of trees added. Directly below clusters of trees, Tmrt could be reduced by between 14.1 °C and 18.7 °C. SOLWEIG also highlighted that more built-up sites showed higher Tmrt under peak warming conditions due to increased radiation loading from 3D urban surfaces, but over the course of the day, open sites were exposed to greater and more uniform Tmrt. This study clearly demonstrates the capacity of street trees to mitigate outdoor thermal stress and provides guidance for urban planners on strategic street tree implementation. 相似文献
10.
《Scientia Horticulturae》2002,95(3):239-249
Microcuttings (shoots each with two leaves) of Limonium ‘Misty Blue’ were cultivated in vitro for 28 days under photoautotrophic (sucrose-free culture medium; CO2 and photosynthetic photon flux (PPF) enriched conditions), photomixotrophic (medium with 30 g l−1 sucrose; CO2 and PPF enriched conditions) and heterotrophic (medium with 30 g l−1 sucrose; CO2 non-enriched conditions) methods. Several growth variables were measured during and at the end of cultivation: shoot fresh and dry weight, percentage of shoot dry matter, root fresh weight, number of leaves, leaf area, chlorophyll and sugar content of leaves, stomatal density and size, net photosynthetic rate (NPR) and percent survival of plantlets ex vitro. Plantlets grown in photoautotrophic and photomixotrophic methods had more leaves, high chlorophyll and sugar contents, high NPR, and showed high percent survival. However, these plantlets possessed less number of stomata per square millimeter. In contrast, the plantlets grown by the heterotrophic method showed decreased values of these growth variables except for the number of stomata per square millimeter. These results indicate that CO2 enrichment for plantlets in vitro at a relatively high PPF would promote photosynthesis and hence growth of chlorophyllous explants/plantlets in vitro. The resulting plantlets were acclimatized better and sooner on ex vitro transplantation. 相似文献
11.
Volatile organic compounds (VOC) are emitted by many plants. In this study, sixty common plant species of the Vidarbha region of Maharashtra, India were examined for VOC (isoprene and monoterpene) emissions. Plant species VOC emission rates ranged from undetectable to 75.2 μg g?1 h?1. Dalbergia sissoo exhibited a maximum VOC emission rate of 75.2 μg g?1 h?1. Ozone forming potentials (OFP) of the sixty plant species were also estimated using the method of Benjamin and Winer (1998). Maximum ozone forming potential of 77 g O3 (tree)?1 d?1 was observed in the case of Mangifera indica. Out of 60 species, 26 species (43.3%) had low OFP (less than 1 g O3 (tree)?1 d?1), 18 species (30%) had medium OFP (less than 1–10 g O3 (tree)?1 d?1) and 16 species (26.7%) had high OFP (more than 10 g O3 (tree)?1 d?1). 相似文献
12.
This paper presents a method that allows sorting of tree and shrub species according to their suitability for planting in urban areas of Madrid (Spain). Suitability was determined from a weighted index for each species according to the severity of damage (biotic, abiotic, and anthropogenic; stem wounds are the main problem in trees, while dead plants are the most important problem in shrubs, seasonal flowers, and vines) and to risk, which was obtained from a new measure, observed Species per Green Area per Year (SAYs). The greater the number of damaged SAYs, the less suitable a species was considered for outdoor planting. For this purpose, 49 green areas corresponding to 141 ha were sampled during 2005–2008. The tree species least recommended for planting include Robinia pseudoacacia, Ulmus sp., Acer negundo, Platanus × hybrid, Populus Boolleana. The shrubs least recommended for planting are Nerium oleander, Cotoneaster sp., Euonymus europaeus, Pyracantha coccinea, and Pittosporum tobira. Statistical analysis reveals that native species have a lower percentage of damaged SAYs than non-native species. 相似文献
13.
In order to optimise the organic components of topsoil mixtures for urban grassland, we conducted two pot experiments, each with seven topsoil mixtures and perennial ryegrass (Lolium perenne) as the experimental crop. The mineral base material of the topsoil mixtures was a blend of crushed bedrock (0–2 mm), sand and agricultural topsoil. The organic components comprised three types of organic waste-based products (WBP), namely sewage sludge (SS), water sludge (WS) and garden-park compost (GPC), which were added in varying ratios to a total amount of 0.3 m3 WBP m?3. In both experiments, mineral nitrogen (N) availability was the key limiting factor for plant growth. Plant growth increased with increasing amounts of the N-rich SS, whereas WS and/or GPC alone resulted in sparse biomass production. Topsoil mixtures with 0.1 m3 m?3 each of SS, WS, GPC or with 0.1 m3 SS m?3 and 0.2 m3 WS m?3 resulted in favourable growth patterns and acceptable soil chemical properties. Topsoil mixtures containing ≤0.1 m3 SS m?3 can therefore be recommended for the establishment of urban grassland. With >0.1 m3 SS m?3, N and phosphorus (P) were applied in excess, causing intensive plant growth and strongly increased readily available phosphorus (P-AL) content in topsoil. We therefore suggest revision of the current Norwegian regulations, which permit inclusion of 0.3 m3 SS m?3 in topsoil mixtures for urban greening. 相似文献
14.
Leaf area of urban vegetation is an important ecological characteristic, influencing urban climate through shading and transpiration cooling and air quality through air pollutant deposition. Accurate estimates of leaf area over large areas are fundamental to model such processes. The aim of this study was to explore if an aerial LiDAR dataset acquired to create a high resolution digital terrain model could be used to map effective leaf area index (Le) and to assess the Le variation in a high latitude urban area, here represented by the city of Gothenburg, Sweden. Le was estimated from LiDAR data using a Beer-Lambert law based approach and compared to ground-based measurements with hemispherical photography and the Plant Canopy Analyser LAI-2200. Even though the LiDAR dataset was not optimized for Le mapping, the comparison with hemispherical photography showed good agreement (r2 = 0.72, RMSE = 0.97) for urban parks and woodlands. Leaf area density of single trees, estimated from LiDAR and LAI-2200, did not show as good agreement (r2 = 0.53, RMSE = 0.49). Le in 10 m resolution covering most of Gothenburg municipality ranged from 0 to 14 (0.3% of the values >7) with an average Le of 3.5 in deciduous forests and 1.2 in urban built-up areas. When Le was averaged over larger scales there was a high correlation with canopy cover (r2 = 0.97 in 1 × 1 km2 scale) implying that at this scale Le is rather homogenous. However, when Le was averaged only over the vegetated parts, differences in Le became clear. Detailed study of Le in seven urban green areas with different amount and type of greenery showed a large variation in Le, ranging from average Le of 0.9 in a residential area to 4.1 in an urban woodland. The use of LiDAR data has the potential to considerably increase information of forest structure in the urban environment. 相似文献
15.
《Scientia Horticulturae》2005,105(3):331-342
The germination of loquat seeds faces certain problems. The present research was designed to study the promotion of the germination of loquat seeds by moist-chilling and GA3 applications. The results showed that loquat seeds display an endogenous dormancy that can be released by moist-chilling treatment for a certain period. In this respect, the best treatment was moist-chilling for 3 weeks at 5 ± 1 °C or 1 week of moist-chilling followed by soaking in 250 ppm GA3 solution for 20 h. These treatments significantly increased germination percentage (88 and 85%, respectively) and decreased time to 50% germination (T50) (31.5 and 40.7 days, respectively) compared to control (51% and 56 days, respectively). Also, the characteristics of the obtained seedlings were much better than the control seedlings. In addition, the 3-week moist-chilled seeds contained the highest soluble protein concentration and were characterized by the synthesis of new protein band of 161.7 kDa that was absent in all other treatments. This treatment lead to the absence of five polypeptides bands (222.5, 201.5, 109.5, 71.1 and 49.3 kDa), which were synthesized in GA3 treatment, and the presence of a higher number of polypeptide bands compared with those of other moist-chilling periods and the control treatments. However, increasing the moist-chilling period over 3 weeks significantly decreased both germination percentage and T50. The combination between GA3 and moist-chilling treatments produced differential effects on seed germination, soluble protein and the number of protein bands depending on the length of the moist-chilling period. Although GA3 application on un-chilled seeds resulted in more synthesis of protein bands than other tested treatments, it did not improve the germination process. The concentration of soluble inorganic phosphorus of the tested seeds was negatively (r = −0.57*) and the concentration of soluble organic phosphorus positively (r = +0.49*) correlated with the germination percentage. It was concluded that treatment of moist-chilling for 3 weeks or 1 week moist-chilling followed by 250 ppm GA3 is recommended for promoting the germination process of loquat seeds and improving growth characteristics of the subsequent seedlings. 相似文献
16.
《Scientia Horticulturae》2005,103(4):387-402
Eggplants (Solanum melongena L. cv. Senryo No. 2) were grown at different levels of soil moisture stress in pots under glasshouse conditions in two separate years. Stress was applied at short-term repetitive (T1), long-term repetitive (T2), and prolonged severe stress (T3) during different growing periods compared with a control (T0). The volumetric water content (VWC) of soil, leaf water potential (Ψp), proline content, transpiration rate (Tr), stomatal conductance (GS) and photosynthesis rate (Pn) of leaves and biomass yield were investigated to verify the extent of injury caused during and after moisture stress. The Ψp decreased in response to stress increase, and it increased to the initial level after stress recovery. Leaf proline synthesis as a compatible solute greatly increased by intensified stress either in the short-term or long-term; the highest value was 51.6 mg g−1 fresh weight (FW) recorded for T3 plants that showed irreversible wilting at 115 times greater than the initial value (0.45 mg g−1 FW). T1 and T2 plants showed a reduced pattern of proline synthesis as they produced 18.8 and 39.9 mg g−1 FW, respectively, which were 42 and 89 times greater than the initial level; but the proline synthesis in these plants was markedly reduced to 1.1 and 5.6 mg g−1 FW, respectively, within a day of stress recovery by rewatering. The Tr, GS and Pn were significantly reduced and varied among the eggplants with stress severity and duration. GS and Pn decreased because of stress and increased again after stress, but not necessarily fully, and did not return to previous levels within a day due to stress injury. Biomass yield was also significantly decreased as the moisture stress retarded the physiological functions. Under short-term and long-term stress conditions, eggplants synthesized proline significantly, but in contrast the net photosynthesis remained less affected and maintained its activity. The results of this study suggest that proline synthesis increases during stress increase and returns to the initial level after stress recovery, which seems to act as part of a survival mechanism. Therefore, eggplants (Solanum melongena L. cv. Senryo No. 2) have an adaptive potential to acclimate under stress conditions. 相似文献
17.
《Scientia Horticulturae》2005,106(3):415-426
The effect of silver nitrate on shoot differentiation and shoot growth was examined in order to improve the regeneration efficiency of pistachio (Pistacia vera L. cv. Kirmizi) in vitro. Nodal explants of in vitro-grown seedlings were used to test various concentrations and combinations of 6-benzyladenine (BA), kinetin (KIN), gibberellic acid (GA3) and silver nitrate (AgNO3). Addition of AgNO3 up to 48.0 μM to the culture medium improved the regeneration frequency and shoot growth, and reduced basal callus formation in all regenerated explants. The highest regeneration frequency (100%) was recorded on Murashige and Skoog (MS) medium containing 9.0 μM BA, 0.2 μM GA3 and 24.0 or 48.0 μM AgNO3 in combination. The best proliferation response in terms of both shoot formation and low callus production was obtained in the medium containing a combination of 9.0 μM BA, 0.2 μM GA3 and 12.0 μM AgNO3. Regenerated shoots, coming from three cycles of subculturing in proliferation media, were rooted in half-strength MS medium containing 12.0 μM indole-3-butyric acid (IBA). Well rooted plantlets were acclimatized and eventually established in peat and perlite. The development and optimization of an effective micropropagation protocol that is presented in this paper can give an important contribution to improve the quality of pistachio plants and, as a consequence, of orchard production in Middle East countries. 相似文献
18.
《Scientia Horticulturae》2001,89(2):115-128
The possible application of some less commonly used in vitro growth regulating compounds is outlined. A number of treatments were applied to determine the best way of inducing in vitro shoot proliferation and rooting on a modified Driver–Kuniyuki [HortScience 19 (1984) 507] basal medium of lemon (Citrus limon (L.) Burm, f. cv. Interdonato) seedlings. 6-Benzyladenine (BA) alone (1, 2 and 4 mg l−1) and in combination with either orange juice (10%, v/v), silver nitrate (3 mg l−1), gibberellic acid (GA3) (0.1 mg l−1 at the establishment stage and 0.5 mg l−1 at all combinations during the proliferation stage) or abscisic acid (ABA) (0.2 mg l−1 only at the establishment stage) were used to stimulate shoot formation during the establishment and the proliferation stage. The combination of BA with ABA gave a high rate of shoot formation, while GA3 and silver nitrate enhanced shoot elongation. When these shoots were transferred to the rooting stage, the effect of application of two different auxins (indole-3-butyric acid (IBA) and α-napthaleneacetic acid) was examined, as well as different methods of application (auxin added to the basal medium and auxin application by dipping the base of the explant in auxin solution). Dipping the base of the explants in a 50% ethanol solution of IBA at 1000 mg l−1 for 5 s resulted in 80% rooting with subsequent 90% survival of these explants, during acclimatization under mist. 相似文献
19.
《Scientia Horticulturae》2005,106(2):190-202
The response of petunia (Petunia x hybrida Vilm.-Andr. ‘Countdown Burgundy’) and impatiens (Impatiens wallerana Hook ‘Accent Orange Tempo’) to Prohexadione-calcium was evaluated under a clear and a far-red light absorbing greenhouse (AFR) film to investigate the dosage effect of Prohexadione-Ca and to determine if it can overcome the flowering delay under FR deficient greenhouse environments. Prohexadione-Ca reduced stem elongation of petunia and impatiens under AFR and clear films when applied 3 weeks after germination. Late applications were less effective. In both crops, main stem length decreased in a quadratic pattern as the concentration of Prohexadione-Ca increased. Under both films, 50–100 mg l−1 Prohexadione-Ca resulted in ≈30% shorter petunia plants. Greater concentrations (500 and 1000 mg l−1) resulted in excessively short plants (over 70%). Prohexadione-Ca at 100 mg l−1 delayed anthesis of petunia by 8 and 3 days under the clear film and the AFR film, respectively during less inductive photoperiods but had no effect during inductive photoperiods. In impatiens, Prohexadione-Ca at 100 mg l−1 delayed anthesis over 10 days under clear or AFR film. Greater concentrations (200 and 300 mg l−1) inhibited flowering of impatiens. Prohexadione-Ca treatments significantly affected flower color development. Untreated petunia plants had dark burgundy flowers. Prohexadione-Ca treatment increased L*, a*, and C* values and decreased hue angle indicating that the flowers were faded. Flowers of untreated impatiens plants were bright orange color. Prohexadione-Ca at 100 mg l−1 increased L* value and decreased a*, b*, and C* values indicating that significant petal fading had occurred. Flowers of treated plants were nearly white under both films. Although effective in height control, loss of color would be a major limitation to the use of Prohexadione-Ca on flowering crops. 相似文献
20.
《Scientia Horticulturae》2005,104(3):325-337
The influence of 24 h mean air temperature (18.3, 20.6, 23.9 and 25.8 °C) and photosynthetic photon flux (PPF; 0.6, 2.1, 3.7 and 4.7 mol m−2 d−1) on the growth cycles of vegetative growth in Ilex × meserveae (‘Blue Princess’ S.Y. Hu) was investigated. Plants propagated from top cuttings were grown in greenhouse compartments. The number of unfolded leaves was recorded continuously throughout the experiment. A modified sine function was fitted to collected data and the values for the amplitude and frequency of the growth curves were analysed. The sine function was tested as a method to evaluate the influence of climate on periodically flushing species. Both amplitude and frequency were significantly influenced by air temperature and PPF. The highest frequency of flushing was found at 23.9 °C and 3.7 mol m−2 d−1. The function resulted generally in a good fit to collected data with R2 values above 0.9. Growth curves of all individual plants were categorised with respect to their growth pattern as poor synchronisation within the treatments did not allow analysis of the mean values of the growth curves. 相似文献