Showing papers in "Journal of Horticultural Science in 1996"
TL;DR: Investigation of whether salinity could be used to control vegetative growth, fruit yield and quality found differences were mainly due to differences in average fruit size, except at 9/9, where after 12 weeks of harvesting, the number of harvested fruits was decreased too.
Abstract: SummaryTomato plants were grown in nutrient film technique at constant, and different, day and night salinity levels to investigate whether salinity could be used to control vegetative growth, fruit yield and quality (size, dry matter percentage, and incidence of blossom-end rot (BER)). Greenhouse experiments were conducted with the following salinity treatments: 5/5, 9/9, 1/9 and 9/1 (day/night salinity levels in dS m−1). The salinity treatments influenced fruit yield clearly: Yield was increased greatly at 1/9. It was decreased at 9/1, although not as much as at 9/9. Yield differences were mainly due to differences in average fruit size, except at 9/9, where after 12 weeks of harvesting, the number of harvested fruits was decreased too. Considering the number of unripe fruits on the plants, in the near future a lower number of harvested fruits was expected at 9/1, and a slightly higher number at 1/9 as compared with 5/5. These differences in the numbers of harvested fruits were partially due to differen...
107 citations
TL;DR: Yield was reduced by severe water stress during each period of the year, but the most sensitive phenological stages were the flowering and fruit set periods, and vegetative growth were affected mainly during the ripening period.
Abstract: SummaryCitrus (Citrus Clementina Hort. ex Tan., cv. Clementina de Nules) were subjected to water stress by withholding irrigation in three periods of the year corresponding to three phenological stages of tree development during 1993 and 1994. Predawn leaf water potential (Ψa) was measured in representative treatments during each period and the water stress integral (SΨ) calculated for all treatments. Actual tree evapotranspiration (ET) was calculated by soil water balance during the intervals of no irrigation and extrapolated from a weighing lysimeter during the irrigation intervals. Both SΨ and ET were found to be good stress indexes with respect to yield and growth parameters, but ET was a better yield predictor. Yield was reduced by severe water stress during each period of the year, but the most sensitive phenological stages were the flowering and fruit set periods. Fruit quality and vegetative growth were affected mainly during the ripening period. A linear correlation was found between relative yie...
99 citations
TL;DR: Complementary irrigation, 80 mm, distributed only during the third stage of fruit development, delayed ripening time and increased fruit size and oil content for fruits of the olive cv.
Abstract: SummaryComplementary irrigation, 80 mm, distributed only during the third stage of fruit development, delayed ripening time and increased fruit size and oil content for fruits of the olive cv. Carolea. Prolonged water deficit reduced fruit growth, oil accumulation rate, K content of the fruit and enhanced ripening and pre-harvest fruit drop. Harvest time affected oil characteristics more than the water availability. Fatty acid composition was not affected by the water regime but polyphenol content increased and alcohol content decreased in the oil produced by irrigated trees.
97 citations
TL;DR: The time for which the stomata remained open or partially open was longer for plants developed under supplemental light at low substrate water content compared with variants grown under natural light and higher soil water content.
Abstract: SummaryPlants of two clonal selections of thyme (Thymus vulgaris) were grown under natural light and natural light supplemented by a PPF of 200 µmol m–2 s–1, provided by high pressure sodium lamps at 90%, 70% and 50% substrate water content in a greenhouse. Stomatal and cuticular transpiration, essential oil glands, epicuticular wax, and morphological traits were measured. Both stomatal transpiration and cuticular transpiration decreased under supplemental light and at low substrate water content. The time for which the stomata remained open or partially open was longer for plants developed under supplemental light at low substrate water content compared with variants grown under natural light and higher soil water content. The number of essential oil glands was significantly higher for plants grown under supplemental light (31 for ‘Laval 1’ and 27/2.27 µm2 for ‘Laval 2’) compared with natural light (23 for ‘Laval 1’ and 19/2.27 µm2 for ‘Laval 2’) grown plants. The lower the substrate water content, the h...
83 citations
TL;DR: In this article, tomato plants were grown in rockwool slabs under glasshouse conditions at different salinities (3 − 9 mS cm−1) and times of the year to assess the possibilities for improving the taste of tomato fruit without reducing fruit quality in other respects.
Abstract: SummaryTomato plants were grown in rockwool slabs under glasshouse conditions at different salinities (3–9 mS cm−1) and times of the year to assess the possibilities for improving the taste of tomato fruit without reducing fruit quality in other respects. Various salts and combinations of salts (comprising Na, K, Ca, Mg, Cl, NO3–N, P and SO4–S) were applied to increase the salinity in the root zone. Yield was reduced by increased salinity due to reduced fruit size whereas the percentage fruit dry matter increased. Blossom-end rot was affected by the various nutrient elements applied to increase the salinity. The ion activity ratios and in the root zone seem to be crucial and more important than the salinity for the development of both internal and external blossom-end rot. The higher the ion activity ratios, the higher is the risk of blossom-end rot. The incidence of internal blossom-end rot exceeded that of external blossom-end rot in spring and autumn.
70 citations
TL;DR: In this article, three freestone peach cultivars Springcrest, Redhaven, and Fayette were studied and related to fruit softening, showing that loss of firmness was accompanied by an increase in ethylene biosynthesis but great variability was observed within the selected fruit populations.
Abstract: SummaryIn the three freestone peach cultivars Springcrest, Redhaven, and Fayette, ethylene evolution was studied and related to fruit softening. Loss of firmness was accompanied by an increase in ethylene biosynthesis but great variability was observed within the selected fruit populations. By plotting data on a single-fruit basis, it appeared that the climacteric was a late event occurring when the fruit had already softened to about 10 to 20 N. The highest values of whole-fruit ethylene evolution at ripening were detected in ‘Springcrest’ . During the earliest phases of softening, whole-fruit ethylene production only rose slightly, whereas a marked increase of 1-aminocyclopropane-l-carboxylicacid (ACC) content, in vivo ACC oxidase activity and ethylene evolution was observed in isolated mesocarp disks, particularly in ‘Springcrest’ and ‘Redhaven’. In the three cultivars, a gradient between epicarp and mesocarp tissue has been detected in terms of ethylene physiology, the former being characterized by a ...
56 citations
TL;DR: In this paper, Golden Delicious were stored for up to six months (a) at low temperature, (b) in controlled atmosphere (3% CO2 and 3% O2), and (c) in ultra-low oxygen (1% CO 2 and 1% O 2) in all three storage regimes.
Abstract: SummaryClimacteric apple fruits cv. Golden Delicious were stored for up to six months (a) at low temperature, (b) in controlled atmosphere (3% CO2 and 3% O2), and (c) in ultra-low oxygen (3% CO2 and 1% O2). The temperature, relative humidity and ethylene concentration were maintained at 1°C, 94% and 100 (µl 1-1 respectively in all three storage regimes. Samples of fruits from each treatment were analysed after four and six months. Treatment (c) gave the firmest fruit, followed by (b) and (a). The cell wall fraction per unit dry weight did not differ quantitatively for each treatment, but showed qualitative differences. The decrease in total pectin and hemicellulose contents with storage period was least in (c), intermediate in (b) and greatest in (a). Cellulose content fell slightly during storage without much differences between each of the storage conditions. The free pectin content of the wall fractions increased least in (c) followed by (b) and (a), and was complementary to wall’s covalently bound pec...
56 citations
TL;DR: In this paper, the main effects of mefluidide treatment seem to be related to induced water stress caused by a reduction in the relative water content (10.5%) and water potential (0.75 MPa) in the leaves and an increase in the stability of biological membranes.
Abstract: SummaryFoliar application of mefluidide, a synthetic plant growth regulator, at 1000 ppm concentration on three year old potted olive plants cv. Frantoio, which is sensitive to frost, induced a hardening effect by increasing the freezing resistance without provoking phytotoxic effects. The main effects of mefluidide treatment seem to be related to induced water stress caused by a reduction in the relative water content (10.5%) and water potential (0.75 MPa) in the leaves and to an increase in the stability of biological membranes. At −18°C, K+, Na+ and Ca++ concentration were lower in the effusate from mefluidide-treated plant leaves than in controls. Electrolyte leakage studies and differential thermal analysis revealed that both the lethal freezing temperature (LT50) and the threshold supercooling temperature were significantly lower in mefluidide-treated than untreated plants. Clear water-soaked areas and permanent browning of tissues were evident in the leaves of treated and untreated olive plants at ...
50 citations
TL;DR: The quantity of starch in the roots increased during the autumn, and the rate of increase was negatively correlated with temperature, which indicates that root starch concentration is higher in autumn than in the summer.
Abstract: SummaryThe effects of temperature and photoperiod on flower and inflorescence initiation during the autumn were investigated in the strawberry cv. Elsanta. The variation in starch under these environmental conditions was also recorded, to test whether this might provide a useful indicator of the onset of imposed and/or true dormancy. Photoperiod had no effect on the rate of flower initiation or final flower number in the primary, secondary or tertiary inflorescences. Temperature had little effect on the final flower number in the primary inflorescence. However, the rate of flower initiation increased linearly with increasing temperature in the secondary (r2 = 0.98) and tertiary inflorescences (r2 = 0.97), to an optimum of 18.6°C in the secondary and 19.9°C in the tertiary inflorescence, and declined at temperatures above these. The quantity of starch in the roots increased during the autumn, and the rate of increase was negatively correlated with temperature. This indicates that root starch concentration ...
49 citations
TL;DR: A hyperbolic model is developed in which it is assumed that Pmax is a function of fruit demand, and the model is defined by two parameters: Pmax, the potential light-saturated photosynthesis, and KD, the initial slope of the response curve of Pmax vs. ...
Abstract: SummaryTo estimate the effect of leaf:fruit ratio on peach leaf light-saturated photosynthesis, experiments were conducted on the early maturing cv. Alexandra in 1992 and late maturing cv. Suncrest in 1992, 1993 and 1994. In early May, the leaf:fruit ratios of bearing shoots were adjusted. The exchange of assimilate between the shoot and the rest of the tree was prevented by girdling the base of the shoot. Leaf photosynthesis measurements were made under saturating irradiance using a portable leaf photosynthesis system. Our results show that there was a significant effect of the leaf:fruit ratio on leaf light-saturated photosynthesis (Pmax). There was a reduction of P*max when the leaf:fruit ratio was high. To describe the effect of fruit demand on photosynthesis, we developed a hyperbolic model in which we assumed that Pmax is a function of fruit demand. The model is defined by two parameters: Pmax, the potential light-saturated photosynthesis, and KD, the initial slope of the response curve of Pmax vs. ...
47 citations
TL;DR: In this paper, semi-hardwood cuttings of Rosa centifolia with the auxin indolebutyric acid (IBA) were found to promote root growth, root number and root length.
Abstract: SummaryTreatment of semi-hardwood cuttings of Rosa centifolia with the auxin indolebutyric acid (IBA) was found to promote rooting. Percentage rooting, root number and root length were enhanced when cuttings were treated with 3500 ppm IBA in a 0.03% solution of potassium hydroxide. Medial and basal cuttings gave a better rooting response than apical and sub-apical cuttings, suggesting that cutting origin may be important for the rooting performance of this species. Rooting percentage and root length appeared to be improved if cuttings were planted in peat:perlite:vermiculite medium as compared with peat:perlite or vermiculite alone. The interaction between IBA concentration, cutting type and media was found to enhance rooting percentage and root number but not root length.
TL;DR: Trees carrying the heavy crop load had lower fruit water potential and higher fruit osmotic potential, and consequently lower fruit turgor potential compared with trees carrying a light crop load, which could improve understanding of the relationship between crop load and fruit size.
Abstract: SummaryMany studies have reported the effect of crop load on leaf water relations of fruit trees but none have dealt with the effect of crop load on water relations of the fruit and how such an effect might influence fruit growth. This is of interest because it could improve our understanding of the relationship between crop load and fruit size. In this study, we measured fruit water potential, fruit osmotic potential, fruit turgor potential and fruit growth, and leaf water potential and leaf conductance on nine-year-old ‘Yanco Queen’ peach ‘Prunus persica (L) Batsch’ trees carrying different levels of crop load. The trees were trained on Tatura trellis and had been either left unthinned (heavy crop load: 450 fruit per tree in 1986 and 560 fruit per tree in 1987) or were thinned (light crop load: 310 fruit per tree). Trees carrying the heavy crop load had lower fruit water potential and higher fruit osmotic potential, and consequently lower fruit turgor potential compared with trees carrying a light crop ...
TL;DR: In field-grown ‘Keitt’ and ‘Tommy Atkins’ mango trees, branches bearing flowering shoots were girdled and defoliated using different lag periods to disrupt transport of the floral stimulus and prevent its production.
Abstract: SummaryDormant buds of mango are nondifferentiated, consisting of an arrested apical meristem and a set of preformed nodes. Cool temperatures around 15°C promote inflorescence (panicle) morphogenesis. Inflorescence differentiation involves a putative floral stimulus generated in mature leaves and translocated in the phloem. In field-grown ‘Keitt’ and ‘Tommy Atkins’ mango trees, branches bearing flowering shoots were girdled and defoliated (or defoliated and then girdled) using different lag periods to disrupt transport of the floral stimulus and prevent its production. The shoots were deblossomed on day 0 to activate growth and differentiation of axillary buds. Only vegetative shoots were produced when branches were girdled and defoliated at the same time. With the maximum lag period of 15 d, about 90% of deblossomed shoots produced axillary inflorescences. Girdled branches that were not defoliated produced inflorescences only. Thus, inflorescence morphogenesis required the presence of leaves during activ...
TL;DR: A complete micropropagation system using juvenile or mature explants of soursop (Annona muricata L.), a tropical fruit tree, was developed and Adventitious bud and shoot proliferation were achieved from hypocotyls of seedlings.
Abstract: SummaryA complete micropropagation system using juvenile or mature explants of soursop (Annona muricata L.), a tropical fruit tree, was developed. Adventitious bud and shoot proliferation were achieved from hypocotyls of seedlings. Lateral shoots were stimulated from the initiated meristems in nodal explants of mature trees. Increasing concentrations of BAP added to the basic Woody Plant Medium stimulated up to four or five shoots per explant in nodal cuttings or hypocotyls, respectively. The addition of NAA with BAP was essential for outgrowth of buds. Rooting was stimulated by galactose and NAA after explants were preconditioned for two weeks in a plain medium containing 10 g l-1 of activated charcoal. The rooted plantlets were acclimatized successfully.
TL;DR: Although IBA had no significant effect on final rooting percentage, root number per rooted cutting was positively related to IBA concentration, values ranging from 6.8–13.8 in the 0 and 250 µg treatments respectively.
Abstract: SummaryVegetative propagation of the edible climber Gnetum africanum Welw. was examined using a low technology non-mist propagation system in Cameroon. Leafy stem cuttings taken from vines growing naturally in a forest reserve were allocated randomly to experimental treatments. Three separate experiments tested respectively: (i) six propagation media, namely sawdust (SD), fine sand (FS), medium sand (MS), gravel (G), and 50:50 mixtures of G:SD and MS:SD; (ii) five IBA concentrations, namely 0, 8, 40, 200 and 250 µg IBA dissolved in 10 µl of alcohol; and (iii) five leaf-area treatments, namely 0, 12.5, 25, 50 and 80 cm2, obtained using paper templates. Propagation medium had a significant effect on final rooting percentage, values ranging from 43–82% in MS:SD and SD respectively. Although IBA had no significant effect on final rooting percentage, root number per rooted cutting was positively related to IBA concentration, values ranging from 6.8–13.8 in the 0 and 250 µg treatments respectively. Rooting perc...
TL;DR: Assimilate supply for vegetative growth was varied by light intensity, by plant density and by fruit, truss and leaf pruning, which led to an increasing dry weight of the vegetative parts of up to 82%, whereas leaf appearance rate was hardly affected.
Abstract: SummaryThe influence of assimilate supply on leaf formation in sweet pepper and tomato was investigated. Assimilate supply for vegetative growth was varied by light intensity, by plant density and by fruit, truss and leaf pruning. In both species, a higher assimilate supply led to an increasing dry weight of the vegetative parts of up to 82%, whereas leaf appearance rate was hardly affected. Area of individual leaves was hardly influenced by fruit or leaf pruning, but increased with increasing light intensity, decreasing plant density or the removal of every other truss. Increased assimilate supply resulted in an increase in dry weight of individual leaves and a decrease in specific leaf area. In addition, for sweet pepper grown under daylight conditions at a constant 24-hour temperature, the rate of dry weight increase of total plant and vegetative parts changed considerably (coefficient of variation (CV) 0.52 and 0.44, respectively), but leaf appearance rate was rather constant during a growing season (...
TL;DR: Wounding cuttings by making a diagonal cut at the end of the stem enhanced rooting, yet the application of 100 ppm NAA negated the beneficial effect, and bruising the stem was detrimental to rooting.
Abstract: SummaryThe rooting of single node leafy stem cuttings from seedlings of Parkia biglobosa (Jacq.) Benth. was examined with respect to provenance, auxin application, basal wounding, and the nodal position on the shoot. Provenances of P. biglobosa from three West African savanna ecozones: Derived, Guinea and Sudan were used for the study. In the absence of auxins and basal wounding, 40% of the cuttings rooted and 80% survived throughout the observation period of 6–8 weeks. However, the addition of auxins and wounding significantly affected the rooting of the cuttings. 100 ppm of the auxin α-napthalene acetic acid (NAA) was more effective than 100 ppm indole-3-butyric acid (IBA). However, when the concentration of both auxins was increased to 200 ppm, IBA was more effective than NAA. In general, wounding cuttings by making a diagonal cut at the end of the stem enhanced rooting, yet the application of 100 ppm NAA negated the beneficial effect. Bruising the stem was detrimental to rooting, except for cuttings f...
TL;DR: Apical cuttings of the difficult-to-root Syringa vulgaris ‘Madame Lemoine’ rooted well only during a brief period of rapid shoot growth in early summer, and even then only when the stockplants had been severely pruned in the previous late winter.
Abstract: SummaryApical cuttings of the difficult-to-root Syringa vulgaris ‘Madame Lemoine’ rooted well only during a brief period of rapid shoot growth in early summer, and even then only when the stockplants had been severely pruned in the previous late winter. Rooting was poor early in the period of shoot growth and, after reaching a peak in early June, declined as shoot growth stopped. The relatively difficult-to-root Cotinus coggygria ‘Royal Purple’ behaved somewhat similarly to Syringa, with rooting being confined to the period of active shoot growth, which was longer than for Syringa, and with a smaller benefit from severe stockplant pruning. Forsythia x intermedia ‘Lynwood’ rooted well throughout the summer regardless of shoot growth rate and earlier pruning severity. In Syringa, the opportunity to enhance rooting, especially in cuttings from the less severely pruned source, by growing shoots temporarily in the dark, was limited to the period of active shoot growth. Producing a late flush of rapidly growing...
TL;DR: The sucrose reduction induced by PCB was effectively reversed by simultaneous GA3 applications, and the involvement of nonstructural sugars in shoot growth of citrus seedlings was studied.
Abstract: SummaryThe involvement of nonstructural sugars in shoot growth of citrus seedlings was studied in ‘Carrizo’ citrange (Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.) rootstocks by foliage applications of gibberellic acid (GA3) and paclobutrazol [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-lyl)penta-3-ol] (PCB) and subsequent determinations of sucrose, glucose, fructose, and starch. PCB inhibited length (21%) and dry weight (19%) of the stem, whereas GA3 increased both (79 and 27%, respectively) in the absence or presence of PCB. On a dry weight basis, GA3 increased hexoses (22.5 mg g−1) and starch (48.4 mg g−1) in shoots (control values were 14.7 and 35.4 mg g−1, respectively), and PCB reduced sucrose (43%) and increased starch (36%). The sucrose reduction induced by PCB was effectively reversed by simultaneous GA3 applications. In roots, GA3 did not modify the levels of the nonstructural sugars, while PCB enhanced the amount of starch (38%). On a per plant basis, GA3 (38.8 mg) ...
TL;DR: In this paper, the authors investigated the effect of mannitol and CaCl2 on apple flesh firmness and found that the amount of insoluble calcium in the flesh increased with increase in the storage period.
Abstract: SummaryApples of cv. Golden Delicious were vacuum infiltrated with 300 mM mannitol, with or without 50 and 150 mM CaCl2. The fruits were stored under low temperature of 2–4°C for 100 d and sampled every 25 d for flesh firmness and transmission electron microscopy. The infiltration of the fruits with 150 mM CaCl2 resulted in higher retention of flesh firmness throughout the storage period, but with 50 mM CaCl2 this could be retained only up to 25 d. The content of insoluble calcium in the flesh increased with increase in the storage period. A large amount of the infiltrated calcium accumulated in walls. However, no relation could be observed between flesh firmness and the amounts of calcium associated with free, ionically bound and covalently bound pectin fractions of the walls. The transmission electron micrographs revealed that most of the changes appeared to involve the middle lamella, and flesh firmness can be judged from the visual inspection of the micrographs. It appears that the effect of calcium i...
TL;DR: Rootstocks significantly influenced mineral content, sugars, sugars and organic acids of the fruit, although these differences are not so important as to affect the commercial value of the Fruit and to direct the choice towards one rootstock rather than another.
Abstract: SummaryThe influence of rootstocks differing in genetic origin and agronomic performance on the commercial characteristics and chemical composition of the fruit was investigated on the low-chill, very early ripening (fruit development period = 100 d) cv. Maravilha (Prunus persica (L.) Batsch) trained to a Y in a high density planting (2,500 trees per ha). Of the rootstocks tested, five belonged to P. persica (Harrow Blood, Ps B2, Ps C14, Rubira and Rutgers Red Leaf), three were hybrids of P. persica x P. dulcis (GF677, Hansen 2168 and Hansen 536) and two were complex hybrids of P. cerasifera (Mr S 2/5, M x P). The more vigorous graft combinations gave significantly higher yields. Rootstocks significantly influenced mineral content (N, K, Fe and Zn), sugars (sucrose and fructose) and organic acids (succinic) of the fruit, although these differences are not so important as to affect the commercial value of the fruit and to direct the choice towards one rootstock rather than another. Neither fruit weight, sk...
TL;DR: There is a general affect of poor pollination resulting in low seed number and low calcium content in cv Braeburn, and lower seed numbers and greater misshapenness were associated with early flowering, inner zones of the tree.
Abstract: SummaryThe effects of high and low pollen availability on seed number and calcium content of ‘Braeburn’ apples have been investigated. Fruit were picked from trees either with or without a nearby pollen source, or from trees without a nearby pollen source but which had been hand-pollinated. With increasing distance from pollinizer trees, fruit had lower seed numbers, increased misshapenness, lower calcium concentrations and increased incidence of bitter pit and lenticel blotch. Hand-pollination resulted in fruit with characteristics similar to those with a nearby pollen source. Lower seed numbers and greater misshapenness of fruit were associated with early flowering, inner zones of the tree. Low calcium contents were associated with low seed numbers, but only in relation to pollinizer treatments and trees. The results suggest that there is a general affect of poor pollination resulting in low seed number and low calcium content in cv. Braeburn.
TL;DR: Carbon partitioning and translocation in one year old fruiting limbs of ‘Elegant Lady’ peach (Prunus persica L. (Batsch) was studied, as affected by source.
Abstract: Carbon partitioning and translocation in one year old fruiting limbs of ‘Elegant Lady’ peach (Prunus persica L. (Batsch)) was studied, as affected by source (leaves on actively growing extension sh...
TL;DR: In this paper, isotta zucchini squash plants (Cucurbita pepo L.) were grown in 157 1 containers and irrigated with water containing 0, 1, 1.5, 2, 2.5 g l−1 of NaCl.
Abstract: ‘Isotta’ zucchini squash plants (Cucurbita pepo L.) were grown in 157 1 containers and irrigated with water containing 0, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9 g l−1 of NaCl. Zucchini squash was mode...
TL;DR: Leaf segments of Prunus persica (L.) Batsch ‘Elberta Queen’ were collected from in vitro-grown proliferating shoots and cultured onto a basal medium supplemented with a wide range of TDZ concentrations (3 to 23 µM), and caulogenesis was observed along cut margins of leaf explants.
Abstract: SummaryLeaf segments of Prunus persica (L.) Batsch ‘Elberta Queen’ were collected from in vitro-grown proliferating shoots and cultured onto a basal medium containing half-strength Murashige and Skoog (MS) salts, Staba vitamins, 30 g l−1 sucrose and 6.5 g l−1 Difco-bacto agar. The influences of six growth regulators supplemented at three levels (5, 10 and 15 µM) on callus induction were investigated under light conditions (16 h photoperiods). For all growth regulator treatments, caulogenesis was observed along cut margins of leaf explants. Among cytokinins tested, thidiazuron (TDZ) induced compact green calli, 6-benzyladenine (BA) and zeatin induced small calli, and kinetin failed to induce callus. For auxin treatments, both dicamba and 2,4-D induced friable white to yellowish calli. In another experiment, leaf explants collected from greenhouse-grown ‘Bellaire’ and in vitro-grown ‘Elberta Queen’ were cultured onto the basal medium supplemented with a wide range of TDZ concentrations (3 to 23 µM). Cauloge...
TL;DR: A greenhouse experiment assessed the effects of two strains of Agrobacterium rhizogenes on softwood cuttings from two sources: ten year old trees of c.
Abstract: SummaryCuttings from trees of jujube (Ziziphus jujuba Mill.), particularly mature ones, root with great difficulty. A greenhouse experiment assessed the effects of two strains of Agrobacterium rhizogenes (A4 and TR105) on softwood cuttings from two sources: ten year old trees of cv. Li and a tree approximately 40 years old of the cv. Contorta. The cuttings were collected and trimmed to 7.5 cm. Ten weeks after inoculation, both strain and source of cutting influenced visible symptoms of infection. Jujube cuttings were more responsive to TR105 than to A4, and the ‘Li’ cuttings were more responsive than ‘Contorta’ cuttings. Strain TR105 was very effective in increasing rooting percentages and root number. ‘Li’ cuttings had better rooting percentages, greater root number, and greater root length than did the ‘Contorta’ cuttings. Inoculation with A. rhizogenes may also possess great potential for promoting adventitious root formation in other difficult woody ornamental or fruit tree species.
TL;DR: A banana tissue culture block, cv Williams, was divided in eight sub-plots each with independent irrigation control, to investigate effects of short-term water stress on the assimilation potential of vigorous plants never previously stressed.
Abstract: SummaryA banana tissue culture block, cv. Williams, was divided in eight sub-plots each with independent irrigation control, to investigate effects of short-term water stress on the assimilation potential of vigorous plants never previously stressed. Supporting studies included recovery from short term water stress, validation of current crop factors of 0.8 × E0 (Autumn/Summer) and 0.5 × E0 (Winter), comparison of USDA class A Pan with tensiometer scheduling, and investigation of specific water demands of tissue culture plantings. Irrigation treatments during an autumn and winter study included a control (“daily” irrigation using A-Pan), a “water stress” treatment (water shortage until severe reductions in assimilation potential occurred) and a “normal” irrigation treatment using currently recommended crop factors. During a summer study, “normal” irrigation was scheduled physiologically, i.e. when plants showed a significant reduction in photosynthesis rate compared with the control. Soil moisture was mon...
TL;DR: The number and size of xylem vessels in the vascular bundles at the proximal and distal positions of both pericarp and placental tissues of tomato fruit were measured in three cultivars with different susceptibilities to blossom-end rot grown at two salinity levels.
Abstract: SummaryThe number and size of xylem vessels in the vascular bundles at the proximal and distal positions of both pericarp and placental tissues of tomato fruit were measured in three cultivars with different susceptibilities to blossom-end rot grown at two salinity levels. While the total number of vascular bundles in the pericarp is greater than in the placenta, the average bundle size in the distal pericarp is larger than that in the distal placenta. Salinity reduced the total bundle area in the distal tissue more in the susceptible cultivars, i.e. Calypso and Spectra than in the less susceptible cultivar, Counter. Both the number and size of xylem vessels in the bundles of proximal placenta tissue were greater than in the proximal pericarp; while the reverse was true in the distal tissue. Salinity reduced the total xylem area in the bundle of the distal tissue significantly, particularly in ‘Spectra’. Thus, the total xylem area in the distal layer was reduced more by salinity in the placenta of the sus...
TL;DR: Experiments were carried out on the effects of storage, light, temperature and depth of sowing on germination and emergence of seeds of dandelion (Taraxacum officinale L.).
Abstract: SummaryExperiments were carried out on the effects of storage, light, temperature and depth of sowing on germination and emergence of seeds of dandelion (Taraxacum officinale L.). Treatments were arranged in factorial combinations of two light regimes, two temperature and four sowing depths in a completely randomized design followed by repeated measurements. Seeds were stored at 4°C and room temperature for nine months. Germination and emergence were tested under light and total darkness at 25°C and 10°C. The emergence tests consisted of 0.0 cm, 1.0 cm, 2.5 cm and 4.0 cm depths of sowing under similar light and temperature conditions to those used for germination tests. Seeds stored at +4°C for nine months had minimum reduction in cumulative germination, but storage at room temperature exceeding three months drastically reduced germination. Light and a higher temperature of 25°C promoted faster, uniform germination, while in darkness, the achievement of 50% of the final germination percentage (T50) was de...
TL;DR: In this paper, the influence of pollination deficit in erratic fruit set is ascertained in orchard conditions and the self-compatibility and intercompatibility relationships among four of the main Spanish apricot cultivars are also studied.
Abstract: SummaryApricot (Prunus armeniaca L.) is a species particularly prone to erratic fruit set. However, the causes of this behaviour are poorly understood since the main limitation in the study of erratic fruit set lies in the difficulty of evaluating all its possible causes in orchard conditions. This results in the eradication of interesting apricot cultivars, such as ‘Moniqui’, in spite of their increasing commercial demand due to their good organoleptic qualities. In this work the influence of pollination deficit in erratic fruit set is ascertained in orchard conditions and the self-compatibility and intercompatibility relationships among four of the main Spanish apricot cultivars are also studied. While ‘Moniqui’ is self-incompatible, ‘Bulida’, ‘Canino’ and ‘Paviot’ proved to be self- compatible. Likewise, all the intercrosses between them behave as compatible. An evaluation of both fruit set and pollen tube behaviour in random and supplementary pollinated flowers with pollen from ‘Canino’ in a commercia...