Molecular characterization of newS-RNases (‘S31’ and ‘S32’) in apple (Malus ×domestica Borkh.)’) in apple (Malus ×domestica Borkh.)

Apple exhibits gametophytic self-incompatibility (GSI) that is controlled by the multiallelic S-locus. This S-locus encodes polymorphicS ribonuclease (S-RNase) for the pistil-part 5 determinant. Information aboutS-genotypes is important when selecting pollen donors for fruit production and breeding of new cultivars. We determined the 5-genotypes of ‘Charden’ (S₂S₃S₄), ‘Winesap’ (S₁S₂₈), ‘York Imperial’ (S₂S₃₁), ‘Stark Earliblaze’ (S₁S₂₈), and ‘Burgundy’ (S₂₀S₃₂), byS-RNase sequencing and S-allele-specific PCR analysis. Two newS-RNases, S₃₁ and S₃₂, were also identified from ‘York Imperial’ and ‘Burgundy’, respectively. These newS-alleles contained the conserved eight cysteine residues and two histidine residues essential for RNase activity. Whereas S₃₁ showed high similarity to S₂₀ (94%), S₃₂ exhibited 58% (to S₂₄) to 76% (to S₂₅) similarity in the exon regions. We designed newS-allele-specific primers for amplifying S₃₁- and S₃₂-RNasc-specific fragments; these can serve as specific gene markers. We also rearranged the apple S-allele numbers containing those newS-RNases. They should be useful, along with anS-RNase-based PCR system, in determining S-genotypes and analyzing new alleles from apple cultivars.     

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.     

Comparison of thermotolerance of sun-exposed peel and shaded peel of ‘Fuji’ apple

The thermotolerance of the sun-exposed peel and the shaded peel of ‘Fuji’ apple (Malus domestica Borkh.) fruit was evaluated by measuring pigments, chlorophyll a fluorescence transients and O₂ evolution or uptake after exposure to 25, 35, 40, 42, 44, 46 or 48 °C for 30 min in the dark. A major effect of heat stress at 46–48 °C on the chlorophyll a fluorescence transients was the appearance of a very clear K step at 200–300 μs for both peel types. The K step was slightly more pronounced in the sun-exposed peel than in the shaded peel, suggesting that the resistance of oxygen-evolving complex to heat stress is slightly lower in the sun-exposed peel than in the shaded peel. Minimal fluorescence (F_O), relative to the value at 25 °C, increased to a greater extent in the shaded peel than in the sun-exposed peel after exposure to 46–48 °C, but the temperature dependencies of F_O changes were similar for both peel types. Maximum quantum yield of PSII (F_V/F_M) decreased to a similar extent in the sun-exposed peel and the shaded peel as temperature rose from 25 to 44 °C, but the sun-exposed peel reached slightly lower values at 46–48 °C. Correspondingly, gross O₂ evolution rate, relative to that at 25 °C, was also slightly lower in the sun-exposed peel than in the shaded peel at 46–48 °C. In response to heat stress, the ratio of Q_A-reducing reaction centers (RCs) to total RCs and the ratio of Q_B-reducing RCs to Q_A-reducing RCs decreased, but both of them decreased to lower values in the sun-exposed peel than in the shaded peel at 46–48 °C, indicating that the capacity of electron transfer between P₆₈₀⁺ and Q_B via Q_A was damaged to a greater extent in the sun-exposed peel than in the shaded peel. At each given temperature, dark respiration was similar between the two peel types. Overall, it appears that the exposure to higher surface temperature under high light does not make the sun-exposed peel more tolerant of heat stress than the shaded peel of apple fruit.     

Isolation of Desulfuromonas acetoxidans cytochrome c-551.5 from the mixed culture ‘Chloropseudomonas ethylica’

The mixed culture ‘Chloropseudomonas ethylica’ strain 2K has been grown on a medium which enhanced the yield of cytochrome c-551.5 from Desulfuromonas acetoxidans. The cytochrome was purified to homogeneity and an isoelectric point of 8.40 was determined. A determination of the amide content indicated that the cytochrome contains two more amides than previously reported.     

The role of Schmidt ‘Antonovka’ in apple scab resistance breeding

??Antonovka?? has long been recognised as a major source of scab (Venturia inaequalis) resistance useful for apple breeding worldwide. Both major gene resistances in the form of the Rvi10 and Rvi17 and quantitative resistance, collectively identified as VA, have been identified in different accessions of ??Antonovka??. Most of the ??Antonovka?? scab resistance used in apple-breeding programmes around the world can be traced back to Schmidt ??Antonovka?? and predominantly its B VIII progenies 33,25 (PI 172623), 34,6 (PI 172633), 33,8 (PI 172612) and 34,5 (PI 172632). Using genetic profile reconstruction, we have identified ??common ??Antonovka?? ?? as the progenitor of the B VIII family, which is consistent with it having been a commercial cultivar in Poland and the single source of scab resistance used by Dr. Martin Schmidt. The major ??Antonovka?? scab resistance genes mapped to date are located either very close to Rvi6, or about 20?C25?cM above it, but their identities need further elucidation. The presence of the 139?bp allele of the CH-Vf1 microsatellite marker known to be associated with Rvi17 (Va1) in most of the ??Antonovka?? germplasm used in breeding suggests that it plays a central role in the resistance. The nature and the genetic relationships of the scab resistance in these accessions as well as a number of apple cultivars derived from ??Antonovka??, such as, ??Freedom??, ??Burgundy?? and ??Angold??, are discussed. The parentage of ??Reglindis?? is unclear, but the cultivar commercialised as ??Reglindis?? was confirmed to be an Rvi6 cultivar.     

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.     

Linkage maps of the apple ( Malus × domestica Borkh.) cvs ‘Ralls Janet’ and ‘Delicious’ include newly developed EST markers

Two apple genetic linkage maps were constructed using amplified fragment length polymorphisms (AFLPs), simple sequence repeats (SSRs), random amplified polymorphic DNAs (RAPDs), and expressed sequence tag (EST)-derived markers in combination with a pseudo-testcross mapping strategy in which the cultivars ‘Ralls Janet’ and ‘Delicious’ were used as the respective seed parents. Mitsubakaido (Malus sieboldii) was used as the pollen parent for each of the segregating F₁ populations. Expressed sequence tag data were obtained from the random sequencing of cDNA libraries constructed from in vitro cultured shoots and maturing fruits of cv ‘Fuji’, which is the offspring of a cross between ‘Ralls Janet’ and ‘Delicious’. In addition, a number of published gene sequences were used to develop markers for mapping. The ‘Ralls Janet’ map consisted of 346 markers (178 AFLPs, 95 RAPDs, 54 SSRs, 18 ESTs, and the S locus) in 17 linkage groups, with a total length of 1082 cM, while that of ‘Delicious’ comprised 300 markers (120 AFLPs, 81 RAPDs, 64 SSRs, 32 ESTs, and the S, Rf, and MdACS-1 loci) on 17 linkage groups spanning 1031 cM. These maps are amenable to comparisons with previously published maps of ‘Fiesta’ and ‘Discovery’ (Liebhard et al., Mol Breed 10:217–241, 2002; Liebhard et al., Theor Appl Genet 106:1497–1508, 2003a) because several of the SSRs (one to three markers per linkage group) were used in all of the maps. Distorted marker segregation was observed in three and two regions of the ‘Ralls Janet’ and ‘Delicious’ maps, respectively. These regions were localized in different parts of the genome from those in previously reported apple linkage maps. This marker distortion may be dependent on the combinations of cultivars used for map construction.     

‘Endogenous yolk’ as the precursor of a possible fertilization envelope in a crab (Carcinus maenas)

After the egg attachment to a maternal ovigerous seta, the Carcinus maenas embryo is enclosed in a tripartite capsule. The innermost layer (envelope 2) which is also the main part of this capsule, is generally detected after egg-laying and is most probably closely related to the fecondation phenomenon. The precursor material of envelope 2, arising from the egg by a massive and very fast exocytosis process, appears as numerous ring-shaped granules. These granules, originated from numerous cortical vesicles perhaps intercommunicating with each others, are observed early in the ooplasm during oogenesis, These so-called ring-shaped granules seem very identical in form with the disc-shaped granules which are classically described as composing the endogenous or intracysternal yolk of many Decapoda crustacean oocytes. In view of our results the role of these granules, in endogenous yolk formation, is re-examined and discussed.     

Evidence for ‘dawn’ and ‘dusk’ oscillators in the Nasonia photoperiodic clock

Females of Nasonia vitripennis were maintained in light cycles from 12 to 72 hr in length, with 4 to 28 hr photoperiods, and their offspring examined for larval diapause. This ‘resonance’ technique revealed periodic maxima of diapause induction, about 24 hr apart. The ‘ascending slopes’ of these maxima appeared to obtain their principal time cue from dusk and the ‘descending slopes’ from dawn. This suggests that two independent—dawn and dusk—oscillators are involved in the Nasonia photoperiodic clock. The results are interpreted in terms of ‘internal coincidence’.N. vitripennis was shown to be able to distinguish between 12 and 18 hr of red light (>600 nm) in the photoperiodic sense. A ‘positive’ resonance experiment using such a red light was also performed. This shows that the spectral sensitivity of the pigment coupling the circadian system to the environmental light cycle extends into the red end of the spectrum.     

Comparative responses of ‘Gala’ and ‘Fuji’ apple trees to deficit irrigation: Placement versus volume effects

Aims

Climate, soil water potential (SWP), leaf relative water content (RWC), stomatal conductance (g_s), fruit and shoot growth, and carbohydrate levels were monitored during the 2008 and 2009 growing seasons to study the responses of ‘Gala’ and ‘Fuji’ apple trees to irrigation placement or volume.

Methods

Three irrigation treatments were imposed, conventional irrigation (CI), partial root-zone drying (PRD, 50% of CI water on one side of the root-zone, which was alternated periodically), and continuous deficit irrigation (DI, 50% of CI water on both sides of the root-zone).

Results

After each irrigation season, DI generated twice the soil water deficit (SWD_int) than PRD (average of dry and wet sides) and a greater integrated leaf water deficit (LWD_int) than PRD and CI. Both PRD and DI reduced g_s by 9 and 15% over the irrigation period. RWC of both PRD and DI was directly related to SWP and inversely related (non-linear) to vapor pressure deficit (VPD), whereas it was unrelated to g_s. Considering individual sampling days, g_s of ‘Gala’ leaves was inversely related to VPD mainly until early August (fruit at cell expansion phase and high VPD), while it was directly related to VPD in September (no fruit and low VPD). On the contrary, g_s of ‘Fuji’ leaves was inversely related to VPD from late August until mid October (low VPD and fruit at cell expansion phase). Fruit growth was not affected by irrigation, whereas shoot and trunk growth was reduced by DI. Irrigation induced sporadic and inconsistent changes in carbohydrate contents or partitioning, with a general tendency of DI leaves to degrade and PRD to accumulate sorbitol and sucrose in dry periods.

Conclusions

‘Gala’ trees exhibited a more conservative water use than ‘Fuji’ trees due primarily to different timing of fruit growth and crop loads. Different levels of SWD_int, rather than changes in stomatal control and carbohydrate partitioning, seem to play a major role in determining a better water status in PRD than in DI trees.     

Metabolic changes in 1-methylcyclopropene (1-MCP)-treated ‘Empire’ apple fruit during storage

??Empire?? apple fruit are more susceptible to flesh browning at 3.3°C if treated with 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception. To better understand the metabolic changes associated with this browning, untargeted metabolic profiling with partial least squares analysis has been used to visualize changes in metabolic profile during hypoxic controlled atmosphere (CA) storage, ethylene insensitivity, and disorder development. Overall, most carbohydrates and organic acids were not appreciably affected, but the levels of amino acids and volatile metabolites were significantly affected, by 1-MCP treatment. Sorbitol and levels of some amino acids were elevated towards the end of storage in 1-MCP treated fruit. CA storage reduced the levels of many volatile components and 1-MCP reduced these levels further. Additionally multiple metabolites were associated with the development of flesh browning symptoms. Unlike other volatile compounds, methanol levels gradually increased with storage duration, regardless of 1-MCP treatment, while 1-MCP decreased ethanol production. Results reveal metabolic changes during storage that may be associated with development of flesh browning symptoms.     

Volatile constituents of Erodium cicutarium (L.) L’ Hérit. (Geraniaceae)

Essential oils from Erodium cicutarium were obtained by hydrodistillation (samples consisting of entire plants (ec1), leaves and stems (ec2)) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS), resulting in a total of 177 components being identified. The essential oils were of a very similar chemical composition and consisted mainly of aliphatic compounds and their derivatives. Fatty acids and fatty acid derived compounds were the most common, 51.3% (ec1) and 60.1% (ec2), followed by carotenoid derived compounds, 12.6% (ec1) and 20.2% (ec2), and then terpenoids, 14.9% (ec1) and 14.2% (ec2). The main constituents in the oils were hexadecanoic acid, 22.8% (ec2) and 35.9% (ec1) and hexahydrofarnesyl acetone, 10.8% (ec2) and 11.6% (ec1). The results obtained differ markedly from those previously reported for the same species.     

‘Communication’ in weakly electric fish, Gnathonemus petersii (Mormyridae) II. Interaction of electric organ discharge activities of two fish

The electric organ discharges (EODs) of pairs of weakly electric fish, Gnathonemus petersii, were simultaneously recorded to study the significance of the EODs as communication signals. In a 400-litre tank a larger fish (12 to 15 cm) was passively moved within a shelter tube toward a smaller specimen (6 to 9 cm), either in steps or a continuous move. The movement was stopped at that distance when at least one fish significantly lowered or ceased its EOD activity. From this ‘threshold interfish distance’ the spatial range of a ‘communication field’ was found to extend about 30 cm from the fish. At threshold distances an EOD frequency increase caused a temporary EOD activity cessation in the second fish. The spontaneous irregular EOD pattern of the fish displaying the increased EOD rate changed into a regular one with almost equal time intervals between fish pulses.     

Effects of Shading on the Synthesis of Volatile Organic Compounds in ‘Marselan’ Grape Berries (Vitis vinifera L.)

Journal of Plant Growth Regulation - Light is a vital environmental factor that can affect the synthesis of volatile organic compounds (VOCs) in grape berries. However, the mechanism through which...     

Experimental analysis of the ‘Paarkultureffekt’ in the protandric polychaete, Ophryotrocha puerilis Clap. Mecz.

Female Ophyrotrocha puerilis Clap. Mecz. were coupled. Certain parts of the prostomium and of the pygidium in one or both partners of a couple were amputated in order to prove that they are responsible for the mutual influence which partners normally exert on their sexual differentiation. The results demonstrate that the palps and the ventrolateral prostomial cirri are the transmitters and the ciliated lateral pits on the prostomium the receivers of the mutual influence. The antennae and the pygidial cirri are not necessary as far as the ‘Paarkultureffekt’ is concerned. The nature of the stimulus is still unknown. At the present stage of these investigations, the favoured conception is of a pheromone transmitted during the contact of the partners.     

Comparison of baltic amber and an ‘aged’ Pinus halepensis resin by means of infrared spectroscopy

The infrared spectrum of ‘aged’ Pinus halepensis resin indicates the presence of a methylene group in a terminal position, which is characteristic of Baltic amber.     

Effect of potassium humate on apple cv. ‘Golden Delicious’ cultured in vitro

The effects of humic substances on in vitro culture of Golden Delicious apple are reported. Potassium humate (KH) when used in proliferation showed a negative interaction with BA while it enhanced rooting when IBA was not present in the culture medium. In the presence of IBA, KH increased root number and reduced root growth. The highest concentration tested, 500 mg l^-1, caused a drastic reduction in root system development. 50 mg l^-1 KH hastened rooting and plants grew more rapidly when transferred to soil.