Drip nitrogen fertigation of ‘Starking Delicious’ apple trees

The response of ‘Starking Delicious’ (Malus domestica Borkh.) apple trees to four N fertigation treatments in drip irrigation (50, 150, 250 and 400 kg N ha⁻¹, supplemented with a uniform dose of 400 kg K ha⁻¹) was investigated in a field experiment during 6 years. Nitrate nitrogen in the soil was proportional (7–58 mg kg⁻¹) to the applied N dose at the end of a 6 week fertigation period in the spring. At other times, the nitrate concentration in the soil was very low. Soil K decreased with depth and in the 0–30 cm soil layer it was negatively correlated with the applied N dose, before fertigation started. At the end of the spring fertigation period, higher K was found in all soil layers analyzed. Vegetative growth was correlated positively with the amount of N applied. Leaf chlorophyll and N were significantly lower only in the lowest N treatment, while increased fruit size and decreased fruit color were measured only in the higher N treatments. Yield was severely biennial. In the ‘On’ years crop load was heavier as less N was applied. An extremely high crop load in the lowest N treatment was followed by a reduced flower density and yield in the following season. In the ‘Off’ years, a significantly higher yield was obtained with the 150 kg ha⁻¹ dose. The dry weights, N, P and K contents of the above ground parts of mature apple trees were determined. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 2342-E, 1988 Series.     

Interactions of calcium,nitrogen and potassium with phosphorus on the symptoms of toxicity in Grevillea cv. ‘Poorinda Firebird’

In two hydroponic experiments it was found that phosphorus induced necrotic leaf symptoms and reduced the growth of Grevillea cv. Poorinda Firebird, a member of the Proteaceae family in which a number of species are known to be affected by phosphorus toxicity. The addition of high levels of calcium was found to aggravate these effects while high nitrogen or potassium levels alleviated them. Tissue analysis of plants receiving high levels of phosphorus showed a tenfold increase in leaf phosphorus compared with plants receiving no phosphorus. Lesser increases were measured in root and stem tissues.     

Genetic transformation of the apple scion cultivar ‘Delicious’ viaAgrobacterium tumefaciens

Transformed shoots of the major apple scion cultivar Delicious (Malus × domestica Borkh.) were obtained by cocultivation withAgrobacterium tumefaciens carrying disarmed plasmids. The transformation efficiency was influenced by the type of plasmid and by the inoculation temperature. Initial selection involved a callus stage followed by shoot regeneration. Shoot regeneration occurred only in the dark. Shoots grew in the light and were rooted in the presence of 100 mg l^–1 kanamycin. Of the range of plasmids tested, the cointegrates pGV 3850::1103neo and pGV 3850::1103gus gave a higher frequency of transformation than the binary vector pGV 3111 × pKIWI. Elongation of transformed shoots was enhanced by culture in a mixture of the cytokinins 6(--dimethylallylamino)purine and 6-benzyladenine. Up to 60% of the elongated shoots rooted in 100 mg l^–1 kanamycin. Transformation was indicated by kanamycin resistance, -glucuronidase assay, nopaline synthesis, and by integration of the T-DNA as judged by Southern analysis.     

Induction of Haploid Morphogenic Calluses from in vitro Cultured Anthers of Prunus Armeniaca cv. ‘Harcot’

Apricot (Prunus armeniaca) ‘Harcot’ anthers, were cultured in vitro for the production of haploid plants. The best androgenic response was achieved with Nitsch and Nitsch (1969) medium, supplemented with 4.52 μM 2,4-D, 4.52 μM zeatin, 2.85 μM IAA and 40 g l⁻¹ sucrose. Cultures were maintained in the dark for 8 days, at 28°C, followed by transfer to a 16-h photoperiod, with 35 μm m⁻² s⁻¹ light intensity and 24/22°C day/night temperature. The androgenic response was correlated with the floral bud size, its phenologic stage and the level of microspore evolution. Anthers containing microspores at the tetrad/uninucleate stage were the most appropriate. The ploidy level of the calluses was evaluated by flow cytometry revealing that they range from haploid to octaploid. Mixoploid calluses have also been identified. Histological studies showed that the haploid calluses have their origin in the microspores. Nodular structures consisting of cells with dense cytoplasm and differentiated xylem elements were observed and were surrounded by an autofluorescent layer, probably due to cutin deposition.     

In vitro regeneration of Alstroemeria cv. ‘Yellow King’ by direct organogenesis

The common techniques for the in vitro production of Alstroemeria plants are based on rhizomes as explants, which have low multiplication rates and a high risk of carrying viral diseases. To overcome these problems, we developed a protocol for the in vitro regeneration of Alstroemeria cv.‘Yellow King’, by testing for shoot induction several explant sources (leaf, stem apices, rhizomes and immature inflorescence apices), temperature and light/dark regimes, hormone and salt concentrations. For shoot multiplication and rooting, several hormone concentrations were tested. We found that only the young floral apices produced adventitious shoots by direct organogenesis. The highest shoot induction rate (10.4 shoots per explant) was obtained by incubation in the dark for 15 days at 8 °C followed by 15 days at 25 °C and a 16-h/8-h light/dark regime, on a Murashige and Skoog (1962) liquid medium at 50% of the salt concentration, supplemented with 2.5 mg l⁻¹ KIN, 1.5 mg l⁻¹ BA and 1.0 mg l⁻¹ NAA, using a piece filter paper to support the explant. The highest shoot multiplication rate (9 shoots per explant) was obtained on a liquid MS medium at full strength supplemented only with BA at 1.0 mg l⁻¹. In vitro rooting of shoots was induced also on a liquid MS medium, either with or without plant hormones.     

Effect of the rootstock on the occurrence of lime-induced chlorosis of potted Vitis vinifera L. cv. ‘Pinot blanc’

The chlorosis susceptible Vitis vinifera L. cv. Pinot blanc was grafted on two hybrid rootstocks with different iron efficiency, as follows: V. Berlandieri × V. rupestris 140 Ru (iron-efficient) and V. riparia × V. rupestris 101-14 (iron-inefficient). The grafted vines were grown in pots of a calcareous and a non-calcareous soil. The shoot growth was periodically checked and leaves, selected at two different times (at the middle of the annual growing period), were assayed for total chlorophyll, ferrous iron, ash alkalinity, percentage of dry matter and chlorosis score. At the end of the growing cycle the roots were oven-dried and weighed. The most significant findings of the trial were: (a) the soil strongly affected the shoot growth, with canes about twice as long in the non-calcareous soil; (b) the iron-efficient rootstock (140 Ru) did not induce chlorosis when growing on the calcareous soil, while the opposite occurred with the iron-inefficient rootstock (101=14); and (c) a high ash alkalinity occurred in light chlorotic leaves compared to green ones, under the same iron concentration.     

Micropropagation of Achillea filipendulina cv. ‘Parker’

Achillea filipendulina (family Asteraceae) is widespread throughout temperate North America. In order to clean stock plants from endemic fungal and bacterial contaminations a method for large-scale propagation of A. filipendulina through meristem culture was sought and found and is described in this paper. The best conditions for propagating A. filipendulina was found to be MS (Murashige and Skoog) salt medium supplemented with 3% sucrose and 1 mg l^–1 IAA (indole-3-acetic acid) plus 2 mg l^–1 BA (6-benzyladenine) under 16 h of cool fluorescent light. Rooted plants were successfully acclimatized within a short time after propagating on this medium. The propagation via tissue culture did not affect plant's presentation. The use of clean stock plants made it possible to increased Israeli production of Achillea from about 150,000 stems a year to about 1,300,000 stems a year.     

Measurement of selected trace elements in Olea europaea L. cv. ‘Sigoise’

BackgroundOlive-trees (Olea europaea L.) are the dominant rustic trees cultivated in the Mediterranean agricultural zones. Major and micronutrients play an indispensable role in their plant physiological functions although; the effect of trace elements on metabolic processes has not been sufficiently investigated, especially in olive-trees.MethodsIn the current study, we have used X-ray fluorescence (XRF) spectrometry to determine selected major and trace elements (Br, Cu, Fe, K, Mn, P, Rb and Zn) in the main olive cultivar cultivated in Algeria, cv.‘Sigoise’. Certified reference materials viz. IAEA-336 (Lichen) and NIST-1646a (Estuarine sediment) were evaluated simultaneously with the soil and plant samples for quality control of the analytical method.ResultsThe results show that Fe and Mn concentrations were superior in leaves than fruits. However large amounts of K, Cu and Rb were accumulated in the olive-fruits. The contents of all chemical elements were above the threshold limits for possible plant nutrient deficiencies, except for P whose concentration was in borderline requirement of olive trees. High values of a translocation factor index were found for K, Cu and Rb (TFs > 4). Principal component analysis (PCA) indicated that K was highly related with olives-fruits, suggesting that the fruit was the principal organ of K storage. Furthermore, dietary element intake through consuming olives was also estimated and compared to recommended daily intakes (RDIs) and daily permissible limits (DPLs). The estimations of chemical element intakes were below the DPLs set by WHO/FAO guidelines for human nutrition.ConclusionThe present work indicates that the concentrations of macro- and microelements (Cu, Fe, K, Mn and Zn) were above the threshold limits for possible plant deficiencies except for P, and this cultivar can easily accumulate high amount of K in their organs (predominance in olives). These findings will be used to achieve efficient fertilization for O. europaea orchards.     

Methyl jasmonate vapor promotes β-carotene synthesis and chlorophyll degradation in Golden Delicious apple peel

Methyl jasmonate (JAMe) vapors (8 ppm) for 4 h at 25°C dramatically increased Golden Delicious apple peel -carotene synthesis by nearly threefold to 35 ng/mm², while control fruits remained nearly constant at 11 ng/mm² during the 10 day measurement period. Chlorophyll a and to a lesser extent chlorophyll b and lutein degradation were accelerated by JAMe treatment, but all showed some recovery after 6 days. Peel chlorophyll ab ratio held almost constant at 4.2–4.5 in control fruits during 10 days, while JAMe-treated apple chl ab ratio decreased linearly to 2.9 during 10 days.     

Micropropagation of Calluna vulgaris cv. ‘H.E. Beale’

Axillary shoot producing cultures were obtained from microcuttings and shoot tips of Calluna vulgaris cv. H.E. Beale. For cultures derived from microcuttings the highest multiplication rate of 38 shoots (5 mm or longer) was obtained on a reduced salt medium with the addition of 0.5 mgl^-1 2-isopentenyladenine (2iP) during an 8 week subculture. For shoot tip derived cultures 0.2 mgl^-1 6-benzyladenine (BA) was the best cytokinin and led to a multiplication rate of 26 for a 6 week subculture. The addition of 1 g/l casein hydrolysate to a multiplication medium enhanced shoot proliferation in presence of 0.5 mgl^-1 BA.Despite various auxin treatments shoots formed no roots in vitro but rooted readily if transferred to a peat substrate ex vitro. A high rooting percentage (80%) was also obtained with shoots taken from the end of a multiplication phase and rooted directly. An additional subculture on low auxin containing media before transfer to peat substrate is recommended because the shoot condition can be improved in this way. A high number of rooted plantlets was produced, so the methods described will allow mass propagation.     

Genetic and biochemical studies on perchloroethylene ‘in vitro’ and ‘in vivo’

Perchloroethylene (PCE) was tested in a diploid strain (D7) of the yeast Saccharomyces cerevisiae in suspension tests with and without a mammalian microsomal activation system (S9) and ‘in vivo’ by the intrasanguineous host-mediated assay. In addition, enzyme alteration studies were performed in mice non-pretreated or pretreated with phenobarbital + β-naphthoflavone. PCE did not induce any genetic effect either ‘in vitro’ or ‘in vivo’. In the suspension test, PCE was more toxic without metabolic activation and less toxic with mammalian microsomal activation. The enzymatic determinations showed an increase of the aminopyrine demethylase activity and of the level of cytochrome P-450.     

Somatic embryogenesis in Rosa chinensis cv. ‘Old Blush’

Plant Cell, Tissue and Organ Culture (PCTOC) - Rose is one of the most widely used ornamental flowers in the world. However, the low induction rates for most rose somatic embryos means that it is...     

In vitro plantlet regeneration of Capsicum chinense Jacq. cv. ‘Bhut jalakia’: hottest chili of northeastern India

Chili (Capsicum chinense) cv. ‘Bhut jalakia’ is used in India for extraction of oleoresin and capsaicin as it is characterized by a very high capsaicin content. The conventional method of propagation of ‘Bhut jalakia’ is through seeds, but this is beset by short viability and low germination rates. Developing a suitable regeneration protocol for ‘Bhut jalakia’ was the focus of this study; as to date, in vitro regeneration for this cultivar has not been investigated. Cotyledon and shoot tip explants were cultured on Murashige and Skoog (MS) media supplemented with different concentrations of cytokinins and auxins. In the case of cotyledon explants, MS medium supplemented with 6-benzylaminopurine (BAP) at 35 μM and kinetin (KIN) at 15 μM were found to be optimal (4.00?±?0.57) for induction of multiple shoots per explant, whereas BAP at 14.8 μM and KIN at 60 μM were best (5.00?±?0.57) for growth of shoot tip explants. Shoots developed from cotyledon explants produced the maximum (8.67?±?0.32) number of roots on MS medium supplemented with low concentration (2.6 μM) of 2-naphthaleneacetic acid (NAA). Supplementation of indole-3-butyric acid (IBA) at 5 μM was found optimal for root formation (16.67?±?2.60) for shoots derived from of shoot tip explants. One month after transfer of in vitro regenerated plantlets to various potting mixes, the highest survival rate (40%) was observed in a mixture of sand, soil, and cow dung in a ratio of 1:1:1. Thus, both shoot tip and cotyledon explants may be cultured on MS medium modified with BAP, IBA, NAA, and KIN to regenerate ‘Bhut jalakia’ chili plants within 90 d.     

Influence of light quality and photoperiod on flowering of Cyclamen persicum Mill. cv. ‘Dixie White’

The effect of light quality (spectral quality) and photoperiod (day length) were studied on flowering of Cyclamen persicum cv. Dixie White. Light generated from light emitting diodes (LED) i.e. monochromatic blue (10 or 12 h per day), monochromatic red (10 or 12 h per day), blue plus red (10 or 12 h per day) and fluorescent lights were used in these studies. It was found that blue plus red LEDs improved flower induction in cyclamen, the number flower buds and open flowers being highest in the plants grown under blue plus red LED (10 h per day). Blue and red LEDs alone reduced the flowering response. Peduncle length (flower stalk length) and blooming period of flowers were also influenced by light qualities and photoperiod treatments. Peduncle length was 23.8 cm on plants grown under red LED (12 h per day) treatment but 14 cm on plants grown under fluorescent light. Blooming period of flowers grown under fluorescent light was 20 d, whereas it was 40 d with the plants grown under red LEDs (10 h per day). The results indicate that flowering and subsequent growth of cyclamen can be controlled by manipulating light quality and lighting period.     

Formation of biphenyl and dibenzofuran phytoalexins in the transition zones of fire blight-infected stems of Malus domestica cv. ‘Holsteiner Cox’ and Pyrus communis cv. ‘Conference’

In the rosaceous subtribe Pyrinae (formerly subfamily Maloideae), pathogen attack leads to formation of biphenyls and dibenzofurans. Accumulation of these phytoalexins was studied in greenhouse-grown grafted shoots of Malus domestica cv. ‘Holsteiner Cox’ and Pyrus communis cv. ‘Conference’ after inoculation with the fire blight bacterium, Erwinia amylovora. No phytoalexins were found in leaves. However, both classes of defence compounds were detected in the transition zone of stems. The flanking stem segments above and below this zone, which were necrotic and healthy, respectively, were devoid of detectable phytoalexins. The transition zone of apple stems contained the biphenyls 3-hydroxy-5-methoxyaucuparin, aucuparin, noraucuparin and 2′-hydroxyaucuparin and the dibenzofurans eriobofuran and noreriobofuran. In pear, aucuparin, 2′-hydroxyaucuparin, noreriobofuran and in addition 3,4,5-trimethoxybiphenyl were detected. The total phytoalexin content in the transition zone of pear was 25 times lower than that in apple. Leaves and stems of mock-inoculated apple and pear shoots lacked phytoalexins. A number of biphenyls and dibenzofurans were tested for their in vitro antibacterial activity against some Erwinia amylovora strains. The most efficient compound was 3,5-dihydroxybiphenyl (MIC = 115 μg/ml), the immediate product of biphenyl synthase which initiates phytoalexin biosynthesis.     

Kinetics of degradation of ‘short-’ and ‘long-lived’ proteins in cultured mammalian cells

Two distinct classes of protein referred to as short- and long-lived (Poole and Wibo, 1973) were found in pulse-chased HeLa S-3 and BHK 21/C13 cells. From experiments with pulse times ranging from 1 min to 20 h, a clear inverse correlation emerged between the pulse length and the percentage of protein which was hydrolysed intracellularly in the first h of chase. Using a 5 min pulse labelling with ³H-leucine, cells were either harvested immediately or after a 2 h chase. Approximately 35% of the label incorporated by cells was lost in a 2h chase; however, electrophoretic separation of cytosol and residual cytoplasmic fractions revealed no significant alteration in their protein profiles. The technique of selectively labelling ‘short’ and ‘long-lived’ proteins, which implies qualitative differences between them, is more readily interpreted as an artificial polarisation of a declining statistical probability curve of proteolysis with time which is similar for all nascent proteins.     

Effect of prostaglandins on α-aminoisobutylic acid uptake in cultured fibroblasts

Effect of various prostaglandins on the uptake of α-aminoisobutylic acid by cultured fibroblasts was studied. All the prostaglandins having an OH functional group in an intramolecular 5-membered ring showed an inhibitory effect on the amino acid uptake. The active compounds can be ranked in potency according to the values for the inhibition of the amino acid uptake per cent of control: prostaglandin F_2α(53 %) >F_1α(54 %) >D₂(56 %) >E₂(62 %) >thromboxane B₂ (66 %). Thus, prostaglandin F_2α was found to be the most potent inhibitor to membrane permeability and the inhibitory effect was dose dependent. The inhibition was maximal after 1 hour of exposure to prostaglandin F_2α, persisted at least up to 6 hours in the presence of prostaglandin F_2α.     

Agrobacterium-mediated transformation of Solanum tuberosum L. cv. ‘Russet Burbank’

Stem sections from shoot cultures maintained in vitro were used to produce transgenic plants of the potato, Solanum tuberosum L. cv. Russet Burbank. Stem internode pieces inoculated with Agrobacterium tumefaciens containing coat protein genes from potato virus X and potato virus Y, produced shoots with a frequency of 60% in the absence of selection and 10% on medium containing 100 mg/l kanamycin monosulfate. Regenerated shoots were assayed for kanamycin resistance by placing stem segments on callus induction medium containing an increased level of kanamycin. Of a total 255 regenerated shoots, 47 (18%) were kanamycin resistant. Of the kanamycin resistant shoots, 25 (53%) expressed the PVX or PVY coat protein genes as assayed by enzyme-linked immunosorbent assay or Western immunoblot analysis.