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1.
Summary

The effects of suboptimal low temperature were investigated on an array of yield, fruit appearance and fruit quality characters in 23 cultivars of melon, Cucumis melo L. The cultivars were grown in two temperature regimes: (I) a heated greenhouse (T1) with temperatures similar to those used in commercial cultivation in the winter in Israel; and (ii) an unheated greenhouse (T2) that had significantly lower night temperatures than T1. Significant differences were found among the cultivars in all characters. Plants from T2 showed an extended fruiting period, more fruits and higher total yield but smaller and lighter fruits than in T1. Fruits from T2 also had significantly more netting and higher amounts of total soluble sugars (TSS), sucrose and fructose than fruits from T1. Hybrid cultivars showed significantly higher electrical conductivity (EC), pH, acidity, TSS, sucrose, fructose and total sugars than open pollinated cultivars. Three trends were found among the characters in respect to the performance of the cultivars between T1 and T2: (a) most cultivars had significantly higher amounts in T2 than T1 (fruit/plant, yield/plant and fructose); (b) only cultivars with amounts below the pooled mean in T1 had higher amounts in T2 (percent dry weight, sucrose, TSS and total sugars); (c) no trend was found between T1 and T2 (mean fruit weight, pH, EC, glucose). Suboptimal low temperatures, when used appropriately, can aid in improving fruit quality.  相似文献   

2.
Three cultivars of 63-day-old hybrid geraniums (Pelargonium × hortorum Bailey) were grown under high (800–1200 mE m?2 s?1), medium (300–600 mE m?2 s?1) or low (100–160 mE m?2 s?1) quantum flux densities. Plants grown under low light and 25% greater total leaf area but 25% lower dry weight than plants grown under medium or high levels, regardless of cultivar. Time to flower in all cultivars was negatively correlated with quantum flux density, and specific leaf weight and leaf thickness were positively correlated to net photosynthetic rate. ‘Sprinter Scarlet’ and ‘Sooner Red’ had similar correlation coefficients (r) for most relationships, but r values for ‘Ringo’ were generally not as strong. Quantum flux density appears to affect both organogenesis and maturation of the flower.  相似文献   

3.
Blueberry plants, Vaccinium ashei Read cultivar ‘Woodard’, were subjected to enhanced UV-B radiation of 15, 24 and 44 UV-B Units under greenhouse conditions to determine the effect of UV-B radiation on certain aspects of vegetative development and fruit growth. Two inflorescences, each with 2 flowers, were left on each plant and hand pollinated at receptivity. Plants exposed to 24 or 44 UV-B units from the time of bud-break had reduced numbers of shoots, numbers of leaves, and leaf area. Berry weight was decreased under 24 and 44 UV-B units and the Mylar control (0.15 UV-B units). Berries grown under 24 UV-B units showed no waxy bloom on the upper exposed surface. Those grown under 44 UV-B units became highly pigmented earlier in their development and at maturity developed a corky layer on the exposed surface.  相似文献   

4.
Plants were grown at 15, 21 or 27°C. Fewer buds were formed at high than at low temperature. At all 3 temperatures, some of the buds aborted. However, the differences in numbers of buds between temperatures did not disappear. Transfer of the plants from 27 to 21°C did not raise the number of buds formed in nodes of which the leaf primordia had already been formed. Therefore, it is plausible that the number of flower buds is determined at a very early stage of node development.  相似文献   

5.
Cuttings from 2 cultivars of Cornus alba propagated in late September produced more and longer roots in long days (LD) than in natural days (ND). The effects of photoperiod on rooting were much less when cuttings were propagated in mid-August. LD during propagation in mid-August delayed the onset of leaf senescence and bud dormancy so that heavier and taller plants were obtained. Bud dormancy did not develop if the plants were grown under LD throughout the winter. Such treatment produced very tall plants and resulted in a greater proportion of their dry matter being distributed to the stems.Short-day (SD) treatment hastened bud dormancy development followed eventually by leaf senescence. Returning the plants to LD after more than 3 months of SD-treatment did not overcome the bud dormancy regardless of whether the plants still had leaves.It is recommended that if material of Cornus alba is propagated in August, the natural photoperiod should be extended during propagation so as to improve plant growth.  相似文献   

6.
Studies on the vernalisation requirements of 7 cultivars of Brussels sprouts showed that, although the puberty stage of glasshouse-grown plants of all cultivars was reached at different chronological ages, they all flowered in response to a low temperature treatment given when they had produced about 15 true leaves and up to a further 15 leaf initials. Plants of different cultivars but either of the same chronological age (91-days old), or at a similar stage of development (20 green leaves), showed differences in response to the duration of low temperature treatment. It is concluded that although all cultivars need to develop approximately 30 nodes (leaves + leaf initials) before they reach puberty, the quantitative response to low temperature is quite different for early, mid-season and late-maturing cultivars.  相似文献   

7.
为了利用色素比较评价不同菠萝品种的农艺性状,选取定植在江门地区的4个菠萝品种叶片为试验材料。结果表明,‘金菠萝’的SPAD值和类胡萝卜素最高,显著高于其他3个品种。‘巴厘’的花青苷含量显著高于其他3个品种,‘卡因’的花青苷含量显著高于‘黄金菠萝’。对于绿色叶片而言,高叶绿素含量品种的叶色深绿,低含量的叶色黄绿;对于彩色叶片植株而言,花青苷含量起主导作用。4个品种在色素含量方面有较大差异,色素可以作为进行菠萝品种评价和鉴别的重要指标。  相似文献   

8.
Eleven cultivars of Chrysanthemum × grandiflorum (Ramat.) Kitam.: ‘Richmond’ and its 10 radiomutants, representing the Lady group, were propagated in vitro with shoot tips and leaves as explants. The aim of this study was to investigate if the explant type used for micropropagation affects the genotype and phenotype of chrysanthemums. Plants grown from shoot tips and adventitious buds formed on leaves were rooted in vitro, acclimatized and cultivated in glasshouse up to full-flowering. The colour and shape of inflorescences of plants obtained from two different explant types were compared within the cultivars. All plants derived from shoot-tip explants showed the inflorescence colour and shape typical for the cultivars. Inflorescence colour of plants derived from adventitious buds were true-to-type in four cultivars: ‘Richmond’, ‘Lady Amber’, ‘Lady White’ and ‘Lady Yellow’. All plants of ‘Lady Apricot’ (originally: golden beet) and ‘Lady Salmon’ (salmon) propagated from adventitious buds technique showed altered inflorescence colour (respectively: purple gold; pink and white). ‘Lady Bronze’ (originally: reddish brown), ‘Lady Orange’ (orange brown) and ‘Lady Rosy’ (purple gold) propagated with adventitious buds had both typical and changed inflorescence colours (respectively: yellow; yellow and red; reddish pink). ‘Lady Vitroflora’ showed altered number of ligulate florets grown into tubes in inflorescence when propagated with shoot tips and leaves as explants. Those changes might be an effect of either chimeral structure or somaclonal variation of the plants investigated. The variation appears only if non-meristematical explants were used. The adventitious buds technique might be useful in chrysanthemum breeding as a source of a new variability.  相似文献   

9.
This work was carried out to study the effects of two soilless media consisting of 80:20 [volume/volume (v/v)] mixtures of mosspeat and perlite, or cocopeat and perlite, on fruit quality and anti-oxidant activities in four cultivars of bell pepper (Capsicum annuum L.): ‘Traviata’ (green), ‘Inspratian’ (red), ‘Aracia’ (orange), and ‘Taranto’ (yellow). The results showed that the composition of the medium had a significant effect on the anti-oxidant composition and activities of the bell pepper fruit. Plants grown on 80:20 (v/v) mosspeat and perlite had significantly higher pericarp firmness, titratable acidity, total phenolic compound concentrations, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, and the hydroxy free-radical (?OH) scavenging ability. Fruit on plants grown on 80:20 (v/v) cocopeat and perlite had significantly higher vitamin C concentrations. Among the four cultivars tested, ‘Inspratian’ (red) was superior in more factors including pericarp thickness, dry matter content, titratable acidity, total soluble solids content, total phenolic concentration, DPPH scavenging ability, and vitamin C concentration. There was a significant interaction between cultivar and soilless medium composition, indicating that the response of bell pepper cultivars varied in the different media. The results of the present study highlight the importance of comparing soilless media in terms of their effect on fruit crop quality and anti-oxidant activity.  相似文献   

10.
Oleander (Nerium oleander L.) is an evergreen shrub of great ornamental interest which, in recent times, has been increasingly used as a flowering pot plant. Plants grown in pots undergo more frequent water stress conditions than those grown in the soil, due to the limited volume of substrate available for the roots. Oleander is a species adaptable to dry conditions and able to survive long periods of drought. It is well known that under water stress conditions all plants reduce photosynthetic activity, resulting in reduced plant growth. In case of severe water stress, leaves undergo strong wilting and senescence resulting in the loss of ornamental value. In the present work, a study was conducted to evaluate the ecophysiological response to water stress in four oleander cultivars previously recognised (on the basis of traits such as size, habit, earliness, abundance and duration of flowering, aptitude for cutting propagation and rapidity of growth) as suitable for pot plant production. Our data confirm the high drought tolerance of oleander. In the studied cultivars, plants submitted to water stress showed only minor variations in leaf gas exchange parameters [transpiration (E), stomatal conductance (gs) and CO2 net assimilation (A)] for at least 10 days without a change in leaf water content [assessed as relative water content (RWC)] for 22 days from the beginning of the stress treatment. During this period, non-irrigated plants maintained the same water status as control plants and were visually undistinguishable from them. Moreover, plants survived without water supply for one month. Following the supply of water again, they were able to restore RWC, gas exchange parameters and instantaneous water use efficiency [A/E ratio (WUEinst)] to the values of control plants. Furthermore, if at the end of the stress period plants appeared withered and were pale green in colour, they regained their normal appearance after they were irrigated again. Although the four studied cultivars showed some minor differences in leaf gas exchange parameters and in the manner in which the latter parameters changed after irrigation was stopped, the response to water stress was essentially the same. Therefore, as far as drought tolerance is concerned, all these cultivars have a good aptitude for use as flowering pot plants.  相似文献   

11.
Infrared radiation, which is responsible for leaf temperatures that exceed the optimal for photosynthesis, was reduced by absorption in an aqueous CuSO4 solution. A small greenhouse was constructed of double acryl plates through which a 0.5% CuSO4 solution was circulated for infrared radiation filtration and cooling. The air temperature in this greenhouse never exceeded 30° C and the leaf temperature of the plants grown in this house was 10% lower than in a glass greenhouse. The yield of tomato plants grown in the acryl greenhouse, with infrared radiation filtration and receiving CO2 enrichment during the entire light period, was not significantly increased as compared with the yield in the glass greenhouse with a similar CO2 concentration. This may have been due to long periods with low light levels caused by extremely rainy and cloudy weather conditions, and by condensation on the inside surfaces of the acryl greenhouse caused by the high humidity.  相似文献   

12.
《Scientia Horticulturae》2001,88(2):147-161
Woody ornamental bare-root plants transplanted in urban areas frequently show poor establishment and occasionally high mortality. Tolerance to different stress factors during transplanting is dependent on plant vitality. The significance of lifting date, in combination with different lengths of time in cold storage, was investigated with 2-year old plants of silver birch (Betula pendula Roth.) and common oak (Quercus robur L.). Plants were grown on a field site in Southern Sweden and were lifted on four occasions, at intervals of 4 weeks, during autumn and early winter. After lifting, plants were stored in a cold store for 90, 135 and 180 days and then (a) xylem water potential in roots and shoots, (b) root growth potential (RGP), (c) mortality and die-back, and (d) shoot and leaf growth were assessed. Lifting bare-root plants of silver birch and common oak too early in the autumn resulted in 62% mortality in birch and 43% in oak, and 31 and 26% die-back in birch and oak, respectively. Plants lifted at a later date showed no mortality in birch and <10% in oak, and almost no die-back. Plants lifted too early in autumn showed decreased root, shoot and leaf growth, compared with those lifted later in the autumn. A longer time in cold storage had a further negative effect on plant vitality in plants lifted too early. Plants lifted later in autumn showed little or no difference in mortality or die-back, for different periods of cold storage, and showed an increase in growth with longer periods of cold storage. Birch plants lifted too early had lower water potential, both in roots and shoots, compared to plants lifted at a later date, while oak plants had the lowest water potential when lifted late. Plants lifted on the first occasion had not been exposed to temperatures below +5°C before lifting, while plants lifted 4 weeks later had been exposed for 67 h to a mean temperature below +5°C. Plants lifted on the first occasion had high mortality and more die-back, while those lifted 4 weeks later showed almost no damage at all. These observations indicate that accumulated exposure to low temperature is probably an important factor in the development of stress tolerance in bare-root plants of silver birch and common oak.  相似文献   

13.
草莓营养钵苗和带土坨苗日光温室生长结果比较   总被引：2，自引：0，他引：2  
日光温室栽培中,种苗质量对草莓产量、品质形成有重要影响.该研究比较了2个草莓品种营养钵苗和带土坨苗在日光温室的生长结果情况,结果表明:营养钵苗的植株株高、叶片数、叶片厚度与带土坨苗的差异较小,不同处理间叶片纵横径、叶柄长度和直径的差异因品种而异.两种类型种苗的物候期差异较小.和带土坨苗相比,使用营养钵苗能显著提高草莓的产量,对果实硬度的影响较小,而处理间植株平均单果重和可溶性固形物含量间的差异因品种而异.因此,和带土坨苗相比,营养钵苗能够显著提高目光温室草莓产量,在生产中具有更大的推广应用价值.  相似文献   

14.
Summary

Selected mature seedling plants were used as stock plants and about half of them were successfully micropropagated. There was no correlation between the ability of petiole expiants to form adventitious shoots and the capacity of these shoots to multiply. Growth and development varied between the micropropagated clones, originating from one seedling each. The colour of the flowers was always constant within a clone. Developmental time, foliage height and the numbers of shoots, leaves and flowers were influenced by the BAP concentration used in vitro. The temperature during the in vitro phase affected the development time and the height of foliage and inflorescences. Increased BAP concentration (from 0 or 0.1 mg l?1 to 1 mg H) resulted in plants with a longer development time to anthesis and more shoots, leaves and flowers. Plants raised on 5 mg l?1 BAP developed slowly, resulting in stunted growth, low foliage height, few leaves and flowers. Consequently, it is possible to use the BAP concentration in vitro to regulate the growth of the progeny crop. After transfer to soil in a growth chamber, plants grown at 10°C in vitro flowered earlier, and had lower foliage and higher inflorescences than plants grown at 21°C. This observation indicates that flowering may be promoted by low temperatures in vitro.  相似文献   

15.
Plants belonging to the genus Ptilotus have immense potential to be developed for the floricultural industry. Many of these plants flower profusely and have potential as cut focal flowers, cut fillers, potted colour or for use in landscape design. Ptilotus nobilis plants produce numerous fragrant cream to pink coloured inflorescences, which exhibit a long vase-life adding to their value as a cut-flower crop. As yet, there is no information published on the key horticultural traits for this species. This work undertook greenhouse trials to evaluate the floricultural attributes for P. nobilis collected from the Cunnamulla region in western Queensland, Australia. As a potted colour crop, P. nobilis may be marketed as a short lived perennial with plants flowering continuously for more than 2 years. From a cut-flower perspective, each plant produced an average of 11 flowering stems per month during December to April, and 8 flowering stems per month during May to August. Flowering stem length and inflorescence length averaged 35.4 and 7.2 cm, respectively for the period November to April, versus 39.2 and 6.3 cm stem and inflorescence lengths, respectively during May to August. As flowering stem lengths range from 17 to 79 cm, there is scope for selection of tall forms for cut flowers and compact forms for potted colour. Furthermore, the harvest duration of flowering stems averaged 43.5 days highlighting the durability of P. nobilis as a cut-flower product. A minimum thermal requirement of 623 growing degree days (GDD) were required to reach flowering after pruning with a predicted base temperature of 0.5 °C and maximum temperature of 18.2 °C when grown in a greenhouse at Gatton, Queensland, Australia. Further work needs to investigate the flowering physiology in response to temperature, photoperiod and light intensity to determine whether flowering can be predicted for different production regions. Also, vegetative propagation methods and field cultural requirements require further investigation to progress the commercial development of this new product.  相似文献   

16.
Film-type antitranspirants and a humidity tent were tested on tissue-cultured chrysanthemum and carnation plants in order to determine the most effective way to increase the vigor and survival of the plants at the time of transfer to a greenhouse. Phytotoxicity necessitated applying most antitranspirants at concentrations lower than that recommended by the manufacturers. Plants grown in the humidity tent were significantly larger and more vigorous than plants in any other treatment. Although a silicone formulation had the greatest effect in reducing transpiration and water stress in transferred plants, it had the adverse effect of stunting plant growth. All other treatments with antitranspirants were ineffective in improving vigor and survival of plants compared to controls.  相似文献   

17.
Transgene expression was evaluated for Gladiolus plants transformed with either the CaMV 35S, double CaMV 35S, rolD, or Arabidopsis UBQ3 promoter controlling the uidA or bean yellow mosaic virus coat protein gene in either the sense or antisense orientation to determine differences in expression for plants grown in the greenhouse and outdoors for two years. There was more variability in GUS expression when plants were grown outdoors than in the greenhouse for two years. Four of the six transformed plant lines with the UBQ3, rolD, and CaMV 35S promoters grown outdoors showed significant differences in GUS expression from year to year as compared to two of the six lines with the UBQ3 and rolD promoters grown in the greenhouse. When grown the same year, two plant lines with the CaMV 35S and one line with the rolD promoter showed 2–16× higher levels of GUS expression outdoors than in the greenhouse, and one plant line with the UBQ3 promoter had 31× higher GUS expression in the greenhouse instead of outdoors. Three of six plant lines transformed with the bean yellow mosaic virus coat protein gene in either the sense or antisense orientation under control of the double CaMV 35S promoter showed obvious transgene expression as compared to three lines that did not show expression or negligible expression for both years when plants were grown both outdoors and in the greenhouse. This study verified long-term gene expression, rather than silencing, for Gladiolus plants when grown outdoors and in the greenhouse from year to year.  相似文献   

18.
Two experiments were undertaken in southern Greece during 2000–2002 in which turnip-rooted parsley was tested for its suitability for cultivation in comparison with locally grown curly-leafed and plain-leafed forms. Plants were harvested when the foliage was acceptable for marketing, rather than on completion of the vegetative cycle, hence root size was relatively small. In year 1, the foliage development of plain-leafed parsley was significantly higher than that of the other two forms, irrespective of sowing date. In year 2, both plain-leafed and curly-leafed parsley produced more foliage than turnip-rooted parsley in the early sowing (November), but not in subsequent sowings (December and February). During both years, root development was higher in turnip-rooted parsley than in curly-leafed parsley, although in the November and February sowings of year 1 the root weight of both plain-leafed and turnip-rooted forms were similar. In all three types of parsley, foliage yield fell off significantly in the spring sowing (February), and in year 1 there was a considerable decrease in root production as well. In most cultivars, foliage weight was higher when plants were grown from transplanted seedlings rather than by direct sowing, whereas the effect of sowing method on root weight was sowing date dependent. Cultivar differences in the foliage weight of direct sown and transplanted plants were reflected by differences in plant height and, in some cases, by leaf number. It is concluded that although overall turnip-rooted parsley produced rather less foliage than that plain-leafed parsley, this was compensated for by the satisfactory production of roots and therefore turnip-rooted cultivars may constitute a suitable crop for introduction to the Mediterranean region.  相似文献   

19.
Plants of Chrysanthemum morifolium Ramat ‘Mountain Peak’, ‘Goldstar’ and ‘Cir Bronze’ were grown in sawdust, sawdust mixed with Ca(NO3)2 7 weeks before planting and held at 20°C (unheated), or at 43°C (heated), and in a sphagnum-peat/vermiculite mix (peat-lite). C:N ratios for the sawdust media at planting were 265.9, 125.7 and 123.3, respectively. Plants grown in each medium received nutrient irrigation containing macro- and microelements, with N at 150, 200 or 250 mg l?1.Days to full flower development, and flower diameter at harvest were not influenced by medium or irrigation N concentration. Plants grown in peat-lite produced the thickest and longest stems, although the stature of plants in all media was judged to be commercially acceptable. Plants grown in unheated sawdust pre-mixed with Ca(NO3)2 produced the thinnest and shortest stems.Leaf concentrations of N, P, K and Mg at harvest were highest in plants grown in peat-lite. Accumulation of Ca, B, Fe, Mn, Cu and Zn was more variable. With the exception of P, foliar nutrient concentrations in all plants were optimal or above published optimal ranges. The onset of flower senescence occurred an average of 1 day earlier in sawdust-grown plants.  相似文献   

20.
By using the leaves with attached intercalary meristems from greenhouse grown stock plants, five cultivars of Cryptanthus were cultured on modified MS media with 4.5 μM NAA and IBA and 3 μM BA to induce adventitious shoot formation from callus tissue. Contamination was 17–21% for explants taken from stock plants which were sprayed weekly with Agribrom and 27–75% for those taken from stock plants which were not treated. More than 99% true to type plantlets were obtained from non-chimeric plants. Green and albino plantlets were obtained from chimeric plants. The chimeric C. ‘Coster's Favorite’ DeCoster also produced a few chimeric plantlets with intermarginal pink stripes in addition to the green and albino plantlets. Most of the non-chimeric plants took a shorter time to produce plantlets of transplantable size (8–12 mm) than the chimeric ones. Except for albino plantlets, survival rate of plantlets exceeded 95%. A minimum average of 500 rooted plantlets can be obtained in a year from a single well-callused leaf explant. The protocol in this report should speed up the mass production and introduction of desirable new cultivars and hybrids of non-chimeric Cryptanthus.  相似文献   

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