Study of some factors affecting the growth and development of myoga (Zingiber mioga Roscoe)

In order to optimise production of the edible flower buds produced by myoga (Zingiber mioga Roscoe) a greater understanding of the growth and development of the plant and factors influencing flower initiation and development are required. The vegetative growth phase in myoga was characterised by a distinct period of pseudostem development from the planted rhizome piece followed by an extended period of rhizome growth from both the base of pseudostems and the planted rhizome piece. The transition from pseudostem formation to the initiation of rhizome growth occurred at the same time as the dry weight of the planted rhizome piece ceased to decline. Flower bud initiation and development occurred over an extended period, beginning soon after the commencement of new rhizome growth and ending prior to foliage senescence. Flower buds were observed at the terminal meristem of first, second, third and fourth order rhizomes. Increasing temperatures stimulated both increased vegetative growth and flower bud initiation and development. Low flower bud yields recorded under conditions of low temperature were the result of reduced rate of floral initiation and not abortion of flower buds. Increased shading of plants grown under glasshouse conditions resulted in reduced flower bud yield and similarly the response resulted from decreased initiation rather than abortion.     

Effects of exogenous application of plant growth regulators on the development of ovule and subsequent embryo rescue of stenospermic grape (Vitis vinifera L.)

Seedless grapevine cultivars (Vitis vinifera L.) are widely grown in Europe, America and Asia. Abortion of zygotic embryos in seedless grapes largely limits the efficiency of breeding of seedless cultivars through genetic crossing. The present study was designed to investigate effects of exogenously applied plant growth regulators (PGRs) to the grapevines in field condition on ovule and subsequent embryo rescue of seedless grapes of small seed traces. First experiment was performed by measuring ovules weight, proportion of each category ovules in maturity and embryo development in vitro of seedless grape cv. Centennial Seedless, Thompson Seedless and Crimson Seedless sprayed by chlormequat (CCC), benzyladenine (BA), ethephon (CEPA) and putrescine (Put). The effects of different application concentration and date of CCC were further evaluated in Centennial Seedless in later experiment. The results showed that exogenous application of all PGRs did not affect the total number of ovules per berries in maturity. CCC increased the ovules weight and proportion of ovules >4 mm in length of three varieties in maturity. The effects of two application times of PGRs on weight of berries and ovules and proportion of each category ovules in maturity were not significantly different. In the proceeding of embryo rescue, CCC at 100 and 1000 mg l⁻¹, BA at 100 mg l⁻¹ and Put at 20 mg l⁻¹ increased the percentage of developed embryos of Centennial Seedless and Thompson Seedless. The results showed that the size of ovules excised for embryo rescue significantly affected embryo formation and plant regeneration. The percentage of embryos formation in ovules >4 mm in length was significantly more than in ovules 2–4 mm in length, no embryo was found in ovules <2 mm in length. Exogenous application of CCC at 100–500 mg l⁻¹ significantly increased percentage of ovules >2 mm in length by 80.0–82.7% in Centennial Seedless, therefore improving embryo formation. The statistical correlation was found between the proportion of ovules >2 mm and embryo formation (r = 0.92) in Centennial Seedless. Among the different spraying time in Centennial Seedless, CCC applied 14 days before bloom produced significantly more ovules >2 mm in length and embryos formation.     

1-Naphthaleneacetic acid and 6-benzyladenine thinning of a common slender spindle ‘Jonagold’/M.9 apple orchard. I: Dose effects and spray distribution in the crowns

Summary

To find the most appropriate rates of application of plant growth regulator (PGR) thinning-agents for a common slender spindle apple (Malus × domestica Borkh.) orchard, different volumes of dilute 1-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) were sprayed ha^?1. Mature ‘Jonagold’/M.9 trees, 3.0 – 3.5 m high and 1.2 – 1.5 m wide, planted in a single row system with 3,030 trees ha^?1, were used. Significant thinning was observed in the case of dilute sprays of NAA at 10 mg l^?1, or BA at 100 mg l^?1, to run-off, using 2,000 l ha^?1 or 1,500 l ha^?1; while 1,000 l ha^?1 did not result in sufficient thinning. Thinning using smaller volumes (250, 500, or 750 l ha^?1) was also significant if the concentration of PGR thinner was proportionally higher (i.e., based on the 1,500 l ha^?1 application rate of more dilute sprays of NAA at 10 mg l^?1 or BA at 100 mg l^?1). Spray distribution measurements in the crowns showed better spray deposits when higher water volumes (i.e., more dilute PGR solutions) were sprayed at all positions (bottom, middle, or top) of the canopy. At 2,000 l ha^?1, 54 – 72% coverage of the leaf area was observed; but, at 250 l ha^?1, coverage was only 10 – 21%. The lower 30% of the canopy was covered poorly when smaller volumes of water (250, 500, or 1,000 l ha^?1) were applied. When 1,500 l ha^?1 was sprayed, good coverage of the lower and upper surfaces of the leaves occurred, and no differences in canopy positions were measured. It was concluded that 1,500 l ha^?1 (i.e., dilute PGR) spraying was the most appropriate volume to use when calculating the dose of NAA or BA to be applied ha^?1 to common (3.0 – 3.5 m-high) mature slender spindle apple orchards on M.9 rootstock. This study was part of the ISAFRUIT Smartfruit Project, aimed at improving existing methods for apple crop regulation with more precise use of PGR thinning agents and with minimum impact on the environment.     

1-Naphthaleneacetic acid and 6-benzyladenine thinning of a common slender spindle ‘Jonagold’/M.9 apple orchard. II: Partial tree spraying

Summary

Mature slender spindle ‘Jonagold’/M.9 apple (Malus × domestica Borkh.) trees were thinned using 10 mg l^–1 1-naphthaleneacetic acid (NAA) or 100 mg l^?1 6-benzyladenine (BA) and an axial fan sprayer at a spray volume of 1,500 l ha^?1 applied to the whole canopy, or with smaller volumes, where only the upper half of each canopy was sprayed. Partial spray applications of NAA or BA (at 1,000 l ha^?1, 750 l ha^?1, or 500 l ha^?1) to the upper half of the trees did not cause any reduction in final fruit numbers on the upper half, or on the lower half of each tree. When the whole tree was sprayed to run-off with the same thinning agent, or at 1,500 l ha^?1, successful thinning on both the upper and lower parts of the canopy occurred. Good spray coverage (from 51% to 77%) was also observed on leaves at all canopy positions measured, when whole trees were sprayed at 1,500 l ha^?1.The development of an innovative crop load regulation strategy was an objective of the ISAFRUIT Smartfruit Project.     

Effects of growth regulators on growth and flowering in Hippeastrum hybridum hort

Soaking of bulbs in 3 concentrations of indoleacetic acid (IAA), gibberellic acid (GA₃), 2-chloroethyltrimethyl ammonium chloride (cycocel) or 2-chloroethylphosphonic acid (ethrel) showed various responses on growth and flowering. IAA increased the weight and number of bulblets, GA₃ increased bulb weight. Cycocel (1000 mg l^?1) increased the number of flowers, while GA₃ increased the diameter of the flowers.Application of IAA at 100 mg l^?1 and GA₃ at 10, 100 or 1000 mg l^?1 twice as foliar spray at an interval of 30 days promoted the number of bulblets on the treated plants, while high concentrations of cycocel and ethrel (1000 mg l^?1) increased the weight of bulblets. All concentrations of IAA, GA₃ and 1000 mg l^?1 cycocel increased the number and size of the flowers.     

Vegetative growth and nutritional status as influenced by auxins and gibberellic acid,and their effect on fruit yield in lemon

Application of 2,4-D and 2,4,5-T at concentrations ranging from 5 to 20 mg l^?1 to 5-year-old ‘Pant Lemon-1’ (Citrus limon Burm) trees reduced the vegetative growth in terms of height, spread, shoot length, number and size of the leaves in the autumn flush. Various NAA treatments (5–20 mg l^?1), however, enhanced growth, but not to the extent that was observed after GA₃ treatments. Application of GA₃ at 10–40 mg l^?1 significantly enhanced all aspects of growth, and the effects were most pronounced at 20 and 40 mg l^?1. Nutritional status of the leaves showed a slight variation in relation to vegetative growth under various treatments.Some 2,4-D- and 2,4,5-T-treatments increased the fruit yield over the control, which could suggest mobilization of foods even at the expense of reduced vegetative growth. On the other hand, NAA, particularly at 10 mg l^?1, increased both vegetative growth and yield, suggesting that the transport of the photosynthates from the leaves to the fruits was not at the expense of new growth extension. Due to excessive growth enhancement under higher concentrations of GA₃ (20 and 40 mg l^?1), comparatively fewer nutrients were translocated to the fruit “sinks”, thereby resulting in a non-significant decrease in yield.     

Nitrogen and calcium nutrition of Petunia × hybrida ‘Coral Sea’

The effects of N and Ca nutrition on plant growth and shoot elemental content of Petunia × hybrida Hort. Vilm. - Andr. ‘Coral Sea’ were evaluated. Nitrogen and Ca were applied separately or in combination in three experiments: (1) N at 0, 100, 200 or 400 mg l^?1; (2) Ca at 0, 75, 150 or 300 mg l^?1; (3) N at 0 or 100 mg l^?1 and Ca at 0 or 150 mg l^?1 combined factorially. Shoot and root dry weights, branch length and flower number were highest when plants received 100 mg l^?1 N. Plants treated with 150 mg l^?1 Ca had the highest shoot and root dry weights. Branch length was maximal at 300 mg l^?1 Ca.Nitrogen and Ca interacted to increase shoot dry weights, branch number and length, leaf area and flower number. Increasing N concentrations increased N and decreased P, Mn and Zn shoot contents. Calcium content of shoots increased while N, P and Mg decreased in response to increasing applications of Ca to petunia plants. Minimal N and Ca tissue concentrations for optimal P. × hybrida growth were 3.3 and 0.67%, respectively.     

Meristem culture and micropropagation of a variety of ginger (Zingiber officinale Rosc.) with a high yield of oleoresin

Summary

Meristems of ginger with or without leaf primordia were induced to form shoots on three-quarter strength Murashige-Skoog’s (MS) medium containing sucrose 6%, coconut milk (CM) 20%, ascorbic acid (AA) 100 mg l^?1, glutamine (GL) 400 mg l^?1, activated charcoal (AC) 250 mg l^?1, 6-benzylaminopurine (BAP) 0.5 mg l^?1, indolebutyric acid (IBA) 0.4 mg l^?1 and agar 0.8%. Meristem-derived shoots exhibited consistent multiplication on three-quarter strength MS medium containing sucrose (3%), AA (100 mg l^?1), AC (100 mg l^?1), BAP (4–5 mg l^?1) and agar (0.8%). Liquid media (agitated or static) were less effective than a solid (agar-gelled) medium for micropropagation. Kinetin and naphthalene acetic acid (NAA) incorporated at various levels (0.01–0.8 mg l^?1) with or without added BAP and IBA neither improved plantlet formation nor enhanced shoot multiplication. The in vitro plants were successfully established in vivo and the rhizome yield was comparable with that of plants grown by conventional methods.     

Effects of growth regulators and activated charcoal on in vitro bulblet multiplication and growth in Galanthus nivalis ‘Flore Pleno’

Summary

The in vitro multiplication of Galanthus nivalis ‘Flore Pleno’ bulblet clumps was evaluated through three 16-week sub-culture passages on media supplemented with either 1.0 mg l^–1 6-benzylaminopurine (BA) and 0.1 mg l^–1 naphthaleneacetic acid [NAA; the plant growth regulator (PGR) control], 0.5 mg l^–1 BA and 0.05 mg l^–1 NAA (PGR/2), or 0.1 mg l^–1 BA and 0.01 mg l^–1 NAA (PGR/10). At the end of the second sub-culture passage, clumps of bulblets from each of the three PGR treatments were also transferred to conditions to promote bulblet growth (G medium without PGRs) supplemented with 60 g l^–1 sucrose and 5 g l^–1 activated charcoal (AC). Lowering the PGR concentration during the initial multiplication phase reduced bulblet multiplication and overall culture growth, but did not influence bulblet size, as indicated by the diameter of the largest bulblet. Lowering the PGR concentration during the multiplication phase also reduced the multiplication of bulblets, overall tissue fresh weight, and the production of roots in tissues transferred to bulblet growth conditions. The reduced growth of tissues previously multiplied on PGR/10 medium was not, however, reflected in the growth of individual bulblets, since these were not significantly smaller than bulblets initially multiplied at the higher PGR concentrations. Bulblet sprouting and root growth on the bulblet growth medium were unaffected by prior PGR status in the multiplication phase. The results are discussed in terms of the mode of action of AC on the promotion of bulblet growth.     

The effect of sucrose,silver thiosulphate and 8-hydroxyquinoline citrate on the quality of Lilium inflorescences cut at the bud stage and stored at low temperature

A continuous supply of sucrose together with 8-hydroxyquinoline citrate to cut Lilium Asiatic hybrid ‘Prima’ inflorescences resulted in buds opening satisfactorily and increased their longevity. The best results were obtained using 30 g l^?1 sucrose. Cut Lilium inflorescences could be stored at 1°C for 4 weeks without a great loss in potential vase-life and decorative value when the inflorescences were pre-treated with silver thiosulphate + 100 g l^?1 sucrose for 24 h before cold storage, kept in a cold room in a solution containing 50 mg l^?1 silver nitrate, and after cold storage kept in a solution containing 30 g l^?1 sucrose and 200 mg l^?1 8-hydroxyquinoline citrate. Such treatment greatly improved bud opening, increased the diameters of individual flowers and prolonged their life.     

Establishment and growth of the rhizome of Alstroemeria as affected by temperature and the root system

The effects of temperature and the root system on growth and establishment were assessed for rhizomes of three Alstroemeria cultivars.-The numbers of lateral rhizomes, aerial shoots and tubers produced by rhizome ‘splits’ were not significantly affected by increase in temperature in the range of 8 to 18°C. Significant increases in root system and rhizome dry weight were seen for cv. Butterfly and in aerial shoot dry weight for all three cultivars used. Increasing temperature significantly decreased the number of plants establishing from rhizome ‘splits’ obtained from plants grown in glasshouse soil. For maximum rhizome production a temperature of between 13 and 18°C was found to be required. A second experiment employing rhizome ‘splits’ from container-grown plants showed no effect of temperature on plant establishment. The presence or absence of the rootsystem on the ‘splits’ at planting was found to be important in plant establishment, with removal of the root system producing a significant decrease in the number of plants establishing. It is suggested that the rootsystem, and damage sustained by it prior to planting, are more important than temperature for the successful establishment of plants of Alstroemeria.     

Physiological response of cauliflower in relation to manganese-boron interaction

Summary

Cauliflower (Brassica oleracea L. var. botrytis) was grown in refined sand at low (0.0011 mg l^?1), normal (0.55 mg l^?1) and excess (5.5 mg l^?1) Mn, each at three levels of B, deficient (0.0033 mg l^?1), normal (0.33 mg H) and excess (3.3 mg l^?1). In Mn deficient cauliflowers a deficiency of B accentuated visible symptoms of Mn deficiency and aggravated the Mn deficiency effects i.e. a decrease in dry matter, leaf Mn, sugars, starch, chlorophyll, Hill reaction and specific activity of aldolase and an increase in the concentrations of proline and inorganic phosphorus. In cauliflowers exhibiting B toxicity symptoms under conditions of excess B, excess Mn increased leaf Mn, sugars, nucleic acids, protein P, nucleic acid P, acid-labile P and leaf B. Excess Mn decreased the concentrations of DNA, protein nitrogen, chlorophyll and activities of peroxidase, aldolase and leaf B, leaf Mn in boron deficient cauliflowers.     

Effects of nitrogen and phosphorus nutrition on the growth of asparagus seedlings

N was applied at 50, 100 or 150 mg l^?1 in factorial combination with P at 7.5, 15 or 22.5 mg l^?1 to asparagus seedlings. There were 6 successional harvests. N and P increased shoot dry weight by increasing mean dry weight and number of shoots. Increasing P had no effect on shoot growth at 50 mg l^?1 N. N increased root dry weight (crown and roots) by increasing root number, whereas P decreased root dry weight due to a decrease in mean root dry weight. N increased total plant dry weight, but P had no effect. N and P increased the partitioning of dry weight to the shoots, while partitioning to the roots increased with time. Plant analysis revealed that 2.6–2.7% N and 0.29–0.36% P, on a dry-weight basis, were present in the shoots at the later harvests with the higher concentrations of N and P. 100–150 mg 1^?1 N in combination with 15 mg l^?1 P produced a seedling suitable for transplanting into commercial fields at 6 weeks from emergence.     

Development of a medium for in vitro culture of Galanthus species based on the mineral composition of bulbs

Summary

To optimise conditions for micropropagating Galanthus species, a basal medium (G) was developed based on mineral analyses of G. nivalis, G. nivalis ‘Flore Pleno’ and G. elwesii bulbs. Compared with Murashige and Skoog (MS) medium, the main features of G medium were increased concentrations of Cu ( 30.4), P ( 3.6), Ca ( 1.9), Mg ( 1.3) and S ( 1.2) and reduced levels of Mn ( 0.07), Zn ( 0.59) and K ( 0.65). The efficacy of G medium in supporting bulblet initiation on bulb chip explants, bulblet multiplication (on media supplemented with 30 g l^–1 sucrose, 1.0 mg l^–1 6-benzylaminopurine and 0.1 mg l^–1 naphthalene acetic acid), and bulblet growth (on plant growth regulator-free media with 60 g l^–1 sucrose and 5 g l^–1 activated charcoal) was compared with MS medium over a range of dilutions (full-, ¹?2-, ¹?4-, and ¹?8-strength). Bulblet initiation was superior on G medium for G. nivalis and G. nivalis ‘Flore Pleno’, but inferior for G. elwesii. The choice of basal medium did not influence bulblet multiplication, although multiplication was reduced on both media diluted to ¹?8-strength. G medium supported bulblet growth and rooting better than MS medium, while dilution of either medium reduced bulblet growth and rooting. Using G medium in place of MS medium during bulblet multiplication greatly reduced hyperhydration with G. elwesii, as did dilution of either of the basal media.     

Nitrogen fertilization under saline conditions in tomato and cucumber plants

Summary

Tomato (Lycopersicon esculentum, Mill.) and cucumber (Cucumis sativus, L.) seedlings were grown in a growth chamber in 4 litre containers filled with nutrient solutions. Four experiments were conducted with four NaCl levels factorially combined with four N levels. The concentrations of NaCl were 4, 25, 50, and 100 mmol l^?1 and 4, 16, 32, and 64 mmol l^?1 in the tomato and cucumber experiments respectively. The N levels in allexperiments were 2, 6, 10 and 15 mmol l^?1 added as NO₃^? or as NH₄⁺ + NO₃^? (2:1). Salinity had a statistically significant negative effect on all responses considered, although the effect was N source-dependent. Addition of N enhanced development of shoot and root dry weights of both species. The optimum N concentration in the nutrient solution varied between 6 and 10 mmol l^?1, although the most appropriate N fertilizer varied with species. Leaf Cl^? concentration decreased in both species when NO₃^? was used as the N source, whereas it increased in the comparative tissues of plants fed with NH₄⁺ + NO₃^?. The effect of treatments on the other nutrients show effects of excess of NaCl, as the form of N source interferes with the uptake of essential nutrients which may cause nutritional disorders.     

Effects of Denapon and Ethrel on thinning grapes

The effectiveness of Denapon and Ethrel as a thinning chemical for ‘Muscat of Alexandria’ grape was examined from 1980 to 1982 with various timings and concentrations of application. Ethrel applied at 50 mg l^?1 by cluster-dipping or shoot-spraying at full bloom, or 6 days after full bloom, resulted in over-thinning and chemical injury, and no thinning effect was found when Ethrel was applied at 10 or 5 mg l^?1 on the same dates. The only treatment which exhibited a desirable thinning effect was shoot-spraying at 50 mg l^?1 12 days after full bloom, but this markedly inhibited berry growth. Denapon applied at 1667 mg l^?1 by shoot-spraying at full bloom, or 6 days after full bloom, reduced the number of berries per cluster almost adequately and consistently without any unfavorable side effects. This chemical applied at 834 mg l^?1 was nearly as effective as when applied at 1667 mg l^?1, but the effectiveness of the former was less consistent than that of the latter. From these results, Denapon is thought to be a promising thinning chemical for ‘Muscat of Alexandria’.     

Large-scale in vitro propagation of giant reed (Arundo donax L.), a promising biomass species

Summary

Giant reed (Arundo donax L.), a promising energy crop, is vegetatively-propagated from fragments of stems and rhizomes. This may limit large-scale cultivation, since it is time-consuming and involves considerable cost and effort. Tissue culture is an alternative to conventional methods of vegetative propagation and may represent a useful tool for large-scale propagation of plants for biomass production programmes. This report describes a protocol for the large-scale in vitro propagation of giant reed by adventitious bud formation. Stem nodes with dormant buds proved to be the most effective to initiate in vitro cultures giving the highest percentage of differentiated shoots (77%) compared to the other plant fractions tested. A sterilisation procedure using 5 g l^–1 HgCl₂ enabled the production of sterile explants. Moreover, early results indicated that late Autumn excision dates not only gave a higher percentage of well-developed shoots ( > 80%), but also a lower level of bacterial contamination (15 – 20%). 6-Benzylaminopurine (BAP) at 3.0 mg l^–1 was most effective in promoting shoot multiplication when added to a basal medium containing Murashige and Skoog (MS) macro- and micro-nutrients, Morel’s vitamins, 30 g l^–1 sucrose, and 7.0 g l^–1 bacteriological agar supplemented with 1.0 mg l^–1 indole-3-acetic acid (IAA) and 0.05 mg l^–1 gibberellic acid (GA₃). Rooting was successfully induced on the same basal medium used for proliferation, modified by halving the MS macro-nutrients and replacing BAP and the other growth regulators with 2.0 mg l^–1 1-naphthaleneacetic acid (NAA). Successful acclimatisation (> 95% survival) of plantlets was carried out, even in late Winter, in a cold greenhouse or under simpler facilities such as shade nets.     

Nitrogen-enriched ground kenaf (Hibiscus cannabinus L.) stem core as a component of soilless growth media

Summary

Four experiments showed that stem core (xylem of kenaf (Hibiscus cannabinus L.) in combination with sphagnum peat moss and fertilizer nutrients was a satisfactory growth medium for plants of ‘Toy Boy’ tomato (Lycopersicon esculentum Mill.). Greater shoot growth was achieved in media containing 20 to 35% kenaf by volume than 50%, and with fine kenaf (2–4 mm diameter) than coarser grades. In the absence of weekly solution fertilization, N-enrichment of the kenaf was necessary to support greater shoot growth than occurred in commercial growth media. Soaking the kenaf in solutions of increasing nitrogen (N) concentration (0 to 15,000 mg N l^?1) increased shoot growth, but urea ammonium nitrate (UAN, 30N–0P–OK) generally resulted in greater shoot growth than 20N–4.4P–16.6K at the same N concentration. The soaking time for kenaf in UAN was considerably less than in the complete fertilizer to produce similar shoot dry weights. Only a small portion of the kenaf in the growth media required pre-plant N enrichment provided the N concentration of the soak solution was increased in ‘ proportion to the volume reduction. Increasing the N concentration of weekly solution fertilization (20N–4.4P–16.6K) from 0 to 500 mg N l^?1 increased shoot growth irrespective of the N concentration of the kenaf soak solution. In media receiving 0 or 100 mg N l^?1 weekly solution fertilization, shoot growth increased with increasing N concentration of the kenaf soak solution.     

Foliar application of chlorocholine chloride improves leaf mineral nutrition,antioxidant enzyme activity,and tuber yield of potato (Solanum tuberosum L.)

In southern China, potatoes (Solanum tuberosum L.) are grown in the late season and the crops are often subjected to low temperature stress particularly during the tuber bulking stage. Exogenous chlorocholine chloride (CCC) treatment has been found to improve crop performance under suboptimal growth conditions; however, the physiological mechanisms underlying the beneficial effects have not been fully understood. The objective of this study was to investigate the effects of CCC treatment on mineral nutrition, antioxidant enzyme system, and tuber yield of potato (cv. Zhongshu 3) under field conditions. The plants were foliar sprayed twice with 1.5, 2.0 and 2.5 g l⁻¹ CCC at 24 and 28 days after emergence (DAE), respectively; and plants without CCC treatment were serviced as control. Leaf samples were collected on 56 DAE for determination of mineral nutrition contents and antioxidant enzyme activity. Results showed that 1.5 and 2.0 g l⁻¹ CCC treatments significantly increased the contents of P, K, Ca, Mg, Fe, Mn, Zn and Cu in potato leaves. These treatments also increased superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT) activities in the leaves. A positive linear relationship was found between SOD activity and the content of Fe + Mn + Zn + Cu. Tuber yield was significantly increased by CCC treatment. It is concluded that treatment with certain concentration of CCC (e.g. 1.5–2.0 g l⁻¹) improves mineral nutrition and SOD, POD and CAT activities in potato leaves; which might have contributed to the higher tuber yield of the crop grown under suboptimal conditions.     

Micropropagation of red raspberry and the influence of phloroglucinol

Micropropagation of 12 raspberry seedling selections and the cultivar ‘Malling Jewel’ has been achieved. A basic culture medium (Linsmaier and Skoog, 1965) supplemented with benzylaminopurine (BAP), 1.0 mg l^?1, and indol-3-yl butyric acid (IBA), 0.1 mg l^?1, was optimal for shoot proliferation. The presence of phloroglucinol (PG) at a concentration of 162 mg l^?1 significantly increased shoot number at all auxin: cytokinin concentrations. Removal of the cytokinin and increasing the concentration of IBA to 1.0 mg l^?1 resulted in adventitious root formation. PG synergistically promoted the number of roots per rooted culture but did not significantly increase the percentage rooting. Viable plants were produced from all genotypes when transplanted to soil.