A comparative study of chlorophyll loss and its related mechanism during fruit maturation in the pericarp of fast- and slow-degreening litchi pericarp     

《Scientia Horticulturae》2005,106(2):247-257

Changes in the levels of chlorophyll a and b and their derivatives, and chlorophyllase activities were compared in the pericarp of ‘Feizixiao’ (slow-degreening) and ‘Nuomici’ (fast-degreening) litchis (Litchi chinensis Sonn.). Cluster bagging and growth regulators were used to regulate the degreening process of ‘Feizixiao’. HPLC analysis revealed the presence of chlorophyllide a, pheophorbide a and pheophytin a as chlorophyll derivatives in litchi pericarp. Loss of chlorophylls in ‘Feizixiao’ pericarp was slower than that in ‘Nuomici’ pericarp. The concentrations of chlorophyll a and b in the pericarp of ‘Feizixiao’ were significantly higher than those in ‘Nuomici’ during fruit maturation, whereas the chlorophyll derivatives in the former were noticeably lower than in the latter. Chlorophyllase activity increased as chlorophylls diminished. Chlorophyllase activity peaked around the colour-break in ‘Nuomici’, being much higher than that in ‘Feizixiao’. Both cluster bagging and treatment with abscisic acid (ABA, 200 mg l⁻¹) or jasmonic acid (50 mg l⁻¹) significantly decreased the chlorophyll content and increased the chlorophyllase activity and the anthocyanin level. In fruit treated with 6-benzyl aminopurine (6-BA, 100 mg l⁻¹) the degradation of chlorophylls was delayed, with concomitant decrease of chlorophyllase activity and anthocyanin level. These results imply that chlorophyllase is the crucial factor in the regulation of the chlorophyll loss in the pericarp.  相似文献   

Effects of IAA and BA on development of globular,heart- and torpedo-stage embryos from cell suspensions of three grape genotypes     

《Scientia Horticulturae》2005,104(3):237-247

In order to initiate cell and embryo suspensions, embryogenic calluses derived on NN solid medium with 2,4-D and BA from petioles of in vitro grown plants of three interspecific grapevine hybrids were cultured in three versions of liquid NN medium: (1) without growth regulators, (2) 0.1 mg l⁻¹ IAA and (3) 0.5 mg l⁻¹ BA. Cell and embryo suspensions were incubated two and three times in these versions of liquid media in various combinations. Incubating suspensions two times in hormone-free media and/or with 0.1 mg l⁻¹ IAA led to formation of globular embryos in the three cultivars studied and small numbers of heart-stage embryos in ‘Podarok Magaracha’ and ‘Intervitis Magaracha’. Numerous heart-stage embryos developed in ‘Intervitis Magaracha’ and ‘Podarok Magaracha’ when the suspensions had been initiated in medium with 0.5 mg l⁻¹ BA, and in ‘Bianca’ this was achieved after two incubations in the above medium. Torpedo-stage embryos were formed after subculturing heart-stage embryo suspensions in medium with 0.1 mg l⁻¹ IAA in all study cultivars. If only small numbers of embryos of a certain developmental heart- or torpedo- stage were formed, such cell and embryo suspensions need to be repeatedly subcultured in liquid medium with specific growth regulators to enable this process.  相似文献   

In vitro induction of tetraploid ginger (Zingiber officinale Roscoe) and its pollen fertility and germinability     

《Scientia Horticulturae》2001,88(4):277-287

In vitro induction of tetraploid ginger (Zingiber officinale Roscoe) and its pollen fertility and germinability were investigated. The growth of shoot tip cultures on agar MS medium containing 2.0 mg l⁻¹ BA was greater than that of similar cultures in liquid MS medium with the same BA concentration. In liquid medium, the combinations of 0.5, 1.0, or 2.0 mg l⁻¹ BA with 0.05 mg l⁻¹ NAA tended to enhance the growth of the cultures. The efficiency of tetraploid induction was assessed by treating shoot tip explants on agar or in liquid MS medium containing 2.0 mg l⁻¹ BA, 0.05 mg l⁻¹ NAA, and 0.2% (w/v) colchicine for 4, 8, 12, and 14 days. The total number of tetraploids induced on solid medium was 18, but only five in liquid medium. On both media, the colchicine treatment for 8 days gave the maximum level of tetraploid induction. Therefore, it was found that the treatment of shoot tip explants on agar medium containing 2.0 mg l⁻¹ BA, 0.05 mg l⁻¹ NAA, and 0.2% (w/v) colchicine for 8 days was the most efficient way of inducing tetraploid ginger. Induced tetraploid strains, ‘4× Kintoki’, ‘4× Sanshu’, and ‘4× Philippine cebu 1’, had higher pollen fertility and germinability than the diploid counterparts, i.e., in the diploid strains, pollen fertility ranged from 0.3 to 6.2% and the germination rate from 0.0 to 0.1%, while in the tetraploid strains, pollen fertility ranged from 27.4 to 74.2% and the germination rate from 4.8 to 12.9%.  相似文献   

The influence of NaCl salinity on growth,yield and fruit quality of strawberry cvs. ‘Elsanta’ and ‘Korona’     

《Scientia Horticulturae》2005,103(3):289-303

In a 2-year field study, strawberry cvs. ‘Elsanta’ and ‘Korona’ were exposed to three different levels of NaCl salinity supplied as aqueous solutions characterised by electrical conductivities of 0.3 dS/m, 2.6 dS/m, and 5.1 dS/m. Salinity in the rhizosphere reduced plant growth by up to 44% in ‘Korona’ and 90% in ‘Elsanta’. A rather distinct cultivar difference represented the reduction in leaf area per plant of 85% in the second year of experiment in ‘Elsanta’ compared to 29% in ‘Korona’. Strawberry can be regarded as a Na⁺ excluder, because Na⁺ content of both strawberry cultivars remained below 3 mg g⁻¹ dry mass at all salinity levels. Cl⁻ content increased considerably, up to 70 mg g⁻¹ dry mass in ‘Korona’ and 80 mg g⁻¹ dry mass in ‘Elsanta’ plants. ‘Korona’ retained most of its Cl⁻ in roots and crowns, whereas in ‘Elsanta’ the maximum was detected in petioles. ‘Korona’ was able to accumulate up to 33% higher Cl⁻ content in the roots than ‘Elsanta’. Macronutrient deficiency due to NaCl salinity was not observed and in comparison to ‘Elsanta’, higher Cl⁻ content in roots of ‘Korona’ did not coincide with an impairment of macronutrient uptake. Salinity stress reduced fruit yield by up to 27% in ‘Korona’ and 64% in ‘Elsanta’. Fruit quality, characterised as taste, aroma, and texture by a consumer-type panel, decreased by more than 24% in ‘Elsanta’, but in ‘Korona’ differences were insignificant. Total soluble solids (Brix) and the ratio Brix/TA (TA, titratable acid) decreased significantly by about 20% in ‘Korona’ and 35% in ‘Elsanta’. To summarise, the ability of ‘Korona’ to retain Cl⁻ in the root system more effectively than ‘Elsanta’ resulted not only in a 41% lower leaf Cl⁻ content at the highest salinity level and a better growth under NaCl stress, but also in a relatively higher fruit yield and fruit quality.  相似文献   

Prohexadione-calcium affects growth and flowering of petunia and impatiens grown under photoselective films     

《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 (A_FR) 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 A_FR 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 A_FR 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 A_FR 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   

Effect of phytohormones on in vitro shoot multiplication and rooting of lime Citrus aurantifolia (Christm.) Swing     

《Scientia Horticulturae》2002,95(4):285-295

Multiple shoots were produced from node explants of lime (Citrus aurantifolia (Christm.) Swing) on MS medium supplemented with 6-benzylaminopurine (BAP), 6-furfurylaminopurine (kinetin) and α-naphthaleneacetic acid (NAA). The highest number of shoots, nine shoots per node, were produced on a medium containing 2 mg l⁻¹ BAP (8.8 μM), 1 mg l⁻¹ kinetin (4.6 μM) and 1 mg l⁻¹ NAA (5.4 μM). Depending on the concentration of BAP and kinetin, NAA either inhibited, stimulated or did not affect shoot multiplication, which also depended on the cytokinin level. Maximum shoot length was obtained from treatments containing 0.5 mg l⁻¹ BAP (2.2 μM) combined with 1 mg l⁻¹ kinetin (4.6 μM) and 0.5 mg l⁻¹ NAA (2.7 μM). The largest leaves of resultant shoots were produced on a medium containing 0.5 mg l⁻¹ each of kinetin (2.3 μM) and NAA (2.7 μM). Transferring in vitro shoots to rooting media containing indole-3-butyric acid (IBA) and NAA produced complete plantlets. The highest rooting percentage was obtained on a medium containing either 1 mg l⁻¹ NAA (5.4 μM) alone or 0.5 mg l⁻¹ NAA (2.7 μM) combined with 2 mg l⁻¹ IBA (9.6 μM), whereas the highest number of roots were produced on a treatment containing both 2 mg l⁻¹ NAA (10.8 μM) and 2 mg l⁻¹ IBA (9.6 μM). Roots elongated most on treatments containing 0.5 mg l⁻¹ of either NAA (2.7 μM) or IBA (2.4 μM). Shoot growth associated with the rooting phase was the highest in response to 2 mg l⁻¹ IBA (9.6 μM) or 0.5 mg l⁻¹ NAA (2.7 μM). Plantlets that survived acclimatization, 82%, exhibited normal growth in soil under greenhouse conditions.  相似文献   

Prohexadione–Ca inhibits vegetative growth of ‘Smoothee Golden Delicious’ apple trees     

《Scientia Horticulturae》2004,101(3):243-253

Experiments to test the effectiveness of prohexadione–Ca as a growth inhibitor in apple trees have been carried out for 3 years in the Middle Ebro Valley (Spain). Also, effects on fruit quality and flower initiation were evaluated. The application of 100–400 mg l⁻¹ of prohexadione–Ca between 12 and 30 days after full bloom (DAFB) to ‘Smoothee Golden Delicious’/M9 apple trees resulted in the inhibition of shoot growth, the effect increasing with concentration, and a greater inhibition was obtained when the trees were first sprayed 12–20 DAFB. A second spray was usually needed to avoid a regrowth of the shoots. The effectiveness of the second application was related to the concentration applied and the date of the first spray. The relative increase in trunk-cross-sectional area was not affected by the growth inhibitor. No negative effects on yield and fruit quality were found except for a reduction of soluble solid content. Flower initiation in the following year was not affected. Concentrations of 100–200 mg l⁻¹ applied shortly after full bloom should be recommended, bearing in mind that a second application might be necessary 6–8 weeks later.  相似文献   

Factors affecting the shoot multiplication of Persian walnut (Juglans regia L.)     

《Scientia Horticulturae》2002,95(3):251-260

A number of experiments were conducted to identify suitable procedure for in vitro shoot multiplication of Persian walnut (Juglans regia L.). Three different nutrient media (DKW, MS and WPM) and three different gelling agents (Phytagel, Difco Bacto agar and a mixture of Phytagel and Difco Bacto agar) were studied in the first experiment. Driver and Kuniyuki walnut (DKW) medium solidified with 2.2 g l⁻¹ Phytagel was found optimum. Performance of explants was better on DKW medium than on MS and WPM. The DKW and MS media were not significantly different from each other, but both of them were significantly better than WPM, which was a very poor medium for this species. Phytagel alone was significantly better than Difco Bacto agar or Phytagel combined with Difco Bacto agar. In another experiment different concentrations of BA were studied. Medium containing 1.0 mg l⁻¹ BA and 0.01 mg l⁻¹ IBA was the best, although medium containing 0.6 and 0.8 mg l⁻¹ BA were also successful, and utilisation of 0.4 mg l⁻¹ BA and 0.01 mg l⁻¹ IBA was optimum for shoot elongation. Application of different kinds of auxins (IAA, IBA and NAA at 0.01 or 0.1 mg l⁻¹) with 1.0 mg l⁻¹ BA were also studied. Media containing IBA were significantly better than media containing IAA for shoot fresh weight, but neither of them was significantly different from media containing NAA. Application of 0.01 mg l⁻¹ or 0.1 mg l⁻¹ auxin, with 1.0 mg l⁻¹ BA, was not significantly different for shoot multiplication of Persian walnut. The morphology of shoots on media containing 0.01 mg l⁻¹ IBA was the best.  相似文献   

An investigation on the effect of different plant growth regulating compounds in in vitro shoot tip and node culture of lemon seedlings     

《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   

Double-phase in vitro culture using sorbitol increases shoot proliferation and reduces hyperhydricity in Japanese pear     

《Scientia Horticulturae》2001,89(3):207-215

This study aimed to improve in vitro shoot proliferation efficiency without inducing hyperhydricity in Japanese pear. The shoot number increased at 2.5–10.0 mg l⁻¹ benzyladenine (BA), while shoot fresh mass increased at 1.0 and 2.5 mg l⁻¹ BA. Different macroelement formulation did not affect shoot proliferation, but adding activated charcoal (AC) to the medium inhibited markedly the production of axillary shoots and biomass and many shoots were hyperhydric. Different carbon sources (CS) significantly increased the shoot number and fresh mass, with the best results for shoot proliferation at 20–30 g l⁻¹ sorbitol. With gelling agents, the shoot number increased at 0.4 and 0.6% agar and 0.3% gellan gum, while fresh mass increased at 0.4% agar. The hyperhydric explants were more than 30% at 0.4–0.6% agar and at any concentration of gellan gum. The improved culture (woody plant (WP) supplemented with 20 g l⁻¹ sorbitol, 0.1 mg l⁻¹ 3-indolyl-butyric acid (IBA), 2.5 mg l⁻¹ BA and 0.8% agar) and double-phase culture (the same medium using a double-phase liquid-gelling agent solidified culture system) produced a higher number of axillary shoots than the conventional culture (1/2MS supplemented with 0.1 mg l⁻¹ IBA, 1.0 mg l⁻¹ BA, 30 g l⁻¹ sucrose and 0.8% agar), moreover, double-phase culture had a higher fresh mass than the other cultures.  相似文献   

Foliar treatment of Mn deficient ‘Washington navel’ orange trees with two Mn sources     

《Scientia Horticulturae》2005,106(1):70-75

The objective of this study was the comparison of the effect of two Mn sources (MnSO₄·H₂O, MnEDTA) which were applied at various concentrations (0, 200, 400, 800, and 1200 mg Mn l⁻¹) to the leaves of ‘Washington navel’ orange trees in order to correct Mn deficiency.One hundred and seventy days after the foliar application of Mn solutions, the mean Mn concentrations in the leaves treated with MnSO₄·H₂O (200, 400, 800 or 1200 mg Mn l⁻¹) or MnEDTA (400, 800 or 1200 mg Mn l⁻¹) were significantly higher than those of the control leaves. Manganese sulfate (MnSO₄·H₂O) was more effective than MnEDTA regarding the improvement of the leaf Mn concentrations of the trees, when applied at equal Mn concentrations. Finally, the leaf Mn concentrations were in the sufficiency range (>25 mg kg⁻¹ d.w.), only after the application of 800 or 1200 mg Mn l⁻¹ as MnSO₄·H₂O.  相似文献   

Establishment and plant regeneration of somatic embryogenic cell suspension cultures of the Zingiber officinale Rosc.     

《Scientia Horticulturae》2005,107(1):90-96

Somatic embryogenic cell suspension cultures of four ginger cultivars were established. Somatic embryogenic calli were induced from ginger shoot tips on MS agar medium supplemented with 1.0 mg l⁻¹ 2,4-D and 0.2 mg l⁻¹ Kn, which contained only half concentration of NH₄NO₃. Rapid-growing and well-dispersed suspension cultures were established by subculturing this kind of callus in the same liquid MSN medium. The suspension cultures (about 1–2 mm in diameter) were placed on the MSN agar medium for callus proliferation. Thereafter embryogenic callus (1.5 cm²) was transferred to solid media (MS + 0.2 mg l⁻¹ 2,4-D + 5.0 mg l⁻¹ BA + 3% sucrose + 0.7% agar). Somatic embryos produced shoots and roots, and shoots developed into complete plantlets on solid MS medium supplemented with 3.0 mg l⁻¹ BA and 0.1 mg l⁻¹ NAA. The relationship between the DW of suspension cultures and pH changes in medium is also discussed. The suspension cultures still kept their vitalities after subculture for 8 months.  相似文献   

Fruit set,seed development and embryo germination in interploid crosses of citrus     

《Scientia Horticulturae》2005,107(1):51-57

Interploid crosses of diploid Kinnow mandarin, Succari sweet orange and Sweet lime with tetraploid Kinnow were made reciprocally for the production of triploid plants. Low fruit set and occurrence of underdeveloped or empty seeds was common in all interploid crosses. The hybrid fruits harvested after 12–14 weeks or 7 months after pollination produced many underdeveloped and few developed seeds; however, tetraploid Kinnow as seed parent yielded more developed seeds per fruit. The under developed seeds were devoid of endosperm. Nucellar embryony was higher in the diploid than in the tetraploid strain of Kinnow. Immature embryos of seeds harvested 12–14 weeks after pollination were cultured in vitro on MS media supplemented with adenine sulphate (20 mg l⁻¹) and malt extract (500 mg l⁻¹). Maximum germination (75%) of hybrid embryos from underdeveloped seeds was obtained in 4× × 2× cross of Kinnow strains. The germinated plantlets were transferred into pots and noted 59–89.3% survival rate in various crosses.  相似文献   

Micropropagation of Karonda (Carissa carandas) through shoot multiplication     

《Scientia Horticulturae》2005,103(2):227-232

Shoot tips from field grown, mature plants of Carissa carandas cv. Pant Sudarshan were cultured on Murashige and Skoog’s (MS) basal medium supplemented with benzyladenine (BA) and indolebutyric acid (IBA) during different seasons. The maximum sprouting rate was obtained with 1.5 cm long explant collected in spring season (February–March) followed by those collected in summer season (April–June). Shoot proliferation was highest on MS basal media supplemented with 3.0 mg l⁻¹ BA. Rooting of microshoots was noted to be the best in 1/2 MS plus 0.8 mg l⁻¹ IBA and 0.2 mg l⁻¹ naphthalene acetic acid (NAA). The rooted plantlets were successfully acclimatized in vermiculite:sand:soil (1:1:1) potting mixture.  相似文献   

The effect of mycorrhizal symbiosis on the development of micropropagated artichokes     

《Scientia Horticulturae》2005,106(4):472-483

In this work, microrosettes of Cynara cardunculus L. var. scolymus Fiori of the “catanese” type were subcultured in a medium supplemented with 6-benzylaminopurine (BAP) (0.05 mg l⁻¹). For root induction, indoleacetic acid (IAA), α-naphthalene acetic acid (NAA) and indole-3-butyrric acid (IBA) were used at three concentrations: 2, 5 and 10 mg l⁻¹. The highest percentage of rooted shoots was aided by the presence of 10 mg l⁻¹ IAA.Once transplanted in pots, the plantlets were inoculated with 10 g Glomus viscosum strain A6 (AM fungus). Acclimatisation was clearly facilitated by the addition of the AM fungus. Indeed, the mycorrhizal plantlets registered a survival of between 90 and 95% for the rooting shoots and 60% for the non-rooting shoots.The botanical characterization of the material produced was carried out in field and was based on several morphological and productive parameters. Data collected confirm the characteristics of the original cultivar, the efficiency of the in vitro propagation material and the possibility of using this technique in early types of artichoke.  相似文献   

Video evaluation of ethylene sensitivity after anthesis in carnation (Dianthus caryophyllus L.) flowers     

《Scientia Horticulturae》2004,99(2):187-197

Differences in ethylene sensitivity among carnation (Dianthus caryophyllus L.) cultivars were evaluated using a time-lapse video recording system. Measurement of time to petal inrolling of ‘White Sim’, ‘Nora’, ‘Chinera’, and line 64-54 flowers subjected to a range of 1–20 μl l⁻¹ ethylene showed that 10 μl l⁻¹ was the optimum concentration for sensitivity evaluation with our video system. With this system we found clear differences in ethylene sensitivity among 10 cultivars and one line. ‘Candy’, ‘Pallas’, ‘Chinera’, and line 64-54 had lower ethylene sensitivities than the other seven cultivars. Line 64-54 had the longest ethylene response time (20.6 h to start of petal inrolling). Video monitoring is a simple and accurate way of evaluating ethylene sensitivity. We have also used the system to study changes in the ethylene sensitivity of carnation flowers after anthesis. We were able to detect a shift in responsiveness to ethylene that was impossible to detect by previous methods. In the Sim-type carnation cultivars tested (‘White Sim’, ‘Scania’, ‘U Conn Sim’, and ‘Nora’), ethylene sensitivity after anthesis decreased significantly with age in both early-cut and late-cut flowers. These results clearly showed that decline of ethylene sensitivity is caused by the increasing physiological age of flowers. Ethylene sensitivity after anthesis decreased with age in normal Sim-type carnations in the same way as in long-vase-life variants such as ‘Sandrosa’.  相似文献   

Arsenic as a factor affecting virus infection in tomato plants: changes in plant growth,peroxidase activity and chloroplast pigments     

《Scientia Horticulturae》2005,105(3):343-358

The influence of arsenic and Cucumber mosaic virus (CMV), applied separately and simultaneously on young tomato plants was studied. The plants were cultivated in containers under glasshouse conditions. Four main variants were arranged. The first one was without additional As pollution of soil, named as a control, and the other three variants, with As added at 25, 50 and 100 mg kg⁻¹ to dry soil respectively. Half of the plants in each experimental container were inoculated with CMV and the rest uninoculated. A clear response in plant behavior under the conditions of biotic and abiotic stress was estimated. Both arsenic and virus infection had a negative effect on tomato plants by limiting the growth of their roots and above growth parts. The changes in roots were more significant than of stems. Virus infection was a stronger stress factor than arsenic applied at levels of 25 and 50 mg kg⁻¹. The effect of each stress factor applied separately was enhanced in cases of their simultaneous application. The strongest negative effect was manifested in the infected plants, treated with excess arsenic of 100 mg kg⁻¹. It was established that the infection, caused by CMV in tomatoes, was affected by the presence of arsenic in the soil and concentration of the latter. Doses of 25 and 50 mg kg⁻¹ were favorable for infection development, while the dose of 100 mg kg⁻¹ was an inhibitor.Virus infection induced stronger specific peroxidase activity (SPOA) than As treatment. The combination of both stress factors reduced the positive peroxidase response caused by virus infection. Arsenic at rate 50 and 100 mg kg⁻¹, virus infection and the combination of both stress factors at 25 mg kg⁻¹ reduced chlorophyll a, chlorophyll b and carotenoid content The virus infection in cases of the higher arsenic doses reduced the As effect. There was an interaction between the two effects of biotic and abiotic stress. When arsenic and virus infection were applied simultaneously, they caused modification of the effect of each stress on the plants, when applied separately.  相似文献   

Influence of nickel-contaminated soils on fenugreek (Trigonella corniculata L.) growth and mineral composition     

《Scientia Horticulturae》2003,98(2):113-119

Leafy vegetables accumulate higher amount of heavy metals like nickel (Ni) due to their more leafy vegetative growth. Therefore, a screenhouse experiment was conducted using an alkaline sandy loam soil equilibrated with graded levels of Ni (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250 and 300 mg kg⁻¹ soil) to assess the Ni accumulation pattern and its influence on growth and micronutrient distribution in fenugreek plants. Green as well as the dry matter yields of fenugreek increased slightly up to 20 g Ni kg⁻¹ soil but decreased significantly with the application ≥40 mg Ni kg⁻¹ soil. Crops showed characteristic toxicity symptoms of interveinal chlorosis in pots receiving ≥40 mg Ni kg⁻¹ soil. While the total content of Ni in the plant tissues increased consistently with increasing rates of applied Ni, the roots accumulated much higher amount of this element compared to the shoot. The content of Fe in plants showed an increase whereas that of Cu and Zn experienced a decrease with the rise in the applied Ni.  相似文献   

Fruit development and ripening in Barbados cherry,Malpighia emarginata DC.     

《Scientia Horticulturae》2002,92(1):1-7

Barbados cherry fruit shows a biphasic pattern of growth whether monitored on a diameter or weight basis. Each growth phase was of about 2 weeks duration with weight gains of equal magnitude but with most of the size increase occurring in the first phase. Pyrene growth paralleled that of the whole fruit. Cell division was limited to the first week of fruit development and horticultural maturity was reached when fruit showed colour break (18 days post-anthesis). Barbados cherry is climacteric with a very high peak respiratory rate (900 ml CO₂ kg⁻¹ h⁻¹) but a low rate of peak ethylene production (3 μl C₂H₄ kg⁻¹ h⁻¹), the former consistent with its high perishability.  相似文献   

Factors controlling high efficiency adventitious bud formation and plant regeneration from in vitro leaf explants of roses (Rosa hybrida L.)     

《Scientia Horticulturae》2001,88(1):41-57

Studies were conducted to improve adventitious bud regeneration in roses (Rosa hybrida L.), specifically to extend the protocol to different genotypes and to initiate production of multiple shoots per explant. The best results were obtained by using a two-stage procedure where excised leaflets were incubated on Murashige and Skoog (MS) (1962) induction medium with 6.8 μM TDZ plus 0.49 μM IBA in the dark for 7 days and subsequently transferred to an MS-based regeneration medium with 2.22 μM BA plus 0.049 μM IBA exposed to a PPFD of 15 μmol m⁻² s⁻¹ PAR. Bud formation capacity was also significantly affected by the genotype and the environment, such as the use of bottom cooling creating a lower RH in the vessel. The addition of silver nitrate to the induction medium also significantly improved the percentage of regeneration in three genotypes tested. Regenerated shoots failed to elongate when transferred to MS proliferation medium containing 0.5 mg l⁻¹ BA, however maximum bud development and elongation were achieved when kinetin in the range 1–2 mg l⁻¹ was used. Elongated shoots were excised and rooted best on zero growth regulator half-strength MS modified medium. Rooted plantlets were acclimatized under greenhouse conditions for evaluation of somaclonal variation.  相似文献