Bulb Growth Research Articles

Nitrogen nutrition of garlic ( Allium sativum L.) under irrigation. Crop growth and development

Garlic was planted on 15 June and 11 August 1983, and fertilised with five levels of nitrogen, in a temperate environment at Pukekohe, New Zealand. Crop growth correlated closely with accumulated temperature, and the crops planted at different times could be compared critically using growing degree days as a base. Quadratic and cubic regressions described the dry matter accumulation of leaves and bulbs, respectively. Fertiliser nitrogen increased the rate of leaf appearance and the rate of leaf extension, particularly for the first leaf, following effects on tissue nitrogen. Bulb growth also responded significantly to applied nitrogen.

Growth and Photosynthesis of Easter Lily in Response to Flower Bud Removal

Abstract Buds or open flowers are often removed in the production of Easter lily (Lilium longiflorum Thunb.) bulbs. To determine if time of flower removal affects bulb size or plant growth, flower buds of container-grown ‘Nellie White’ plants were removed when the length of the largest flower bud was 1.0 cm (early) or 3.5 cm (late). Net photosynthesis of the 5th (upper) and 25th (mid-shoot) leaves was monitored and plants were harvested 2 months after full bloom of intact controls. Early disbudding stopped pedicel growth, inhibited stem elongation, and reduced total leaf area 12%, but did not affect bulb weight. Stem elongation was inhibited less by late disbudding; leaf area and plant weight were unaffected. Both fresh and dry bulb weights of late disbudded plants increased by 15%. Early disbudding reduced the rate of net photosynthesis of leaf 5 (particularly during the 3 weeks following full bloom), whereas late disbudding had less effect. Treatments did not affect photosynthesis of leaf 25. Reduced stem growth under late disbudding, without a severe reduction in photosynthesis, may have increased the availability of assimilate for bulb growth. Early disbudding caused 81% of the daughter bulbs to sprout prematurely, compared to 27% for late disbudding and 9% for controls. In a field study, removing flower buds at 1.5 cm or 4.0 cm in length increased bulb fresh weight over intact controls by 12% and 30%, respectively. Disbudding did not increase sprouting of field-grown plants. Delaying removal until the first flower bud is 3.5–4.0 cm long reduces deleterious effects on shoot growth while significantly improving bulb size.

Effect of temperature on bulb growth capacity and sensitivity to summer sprouting in Lilium longiflorum Thunb.

The production of Lilium longiflorum bulbs in The Netherlands, with its cool climate, has been a problem because of unsatisfactory bulb growth and the risk of premature sprouting of the daughter bulbs (summer sprouting). To investigate the possibilities of breeding a type of L. longiflorum that can be grown under cool climatic conditions, a collection of 27 L. longiflorum cultivars from Japan, The Netherlands and the United States was tested, together with two Asiatic hybrids and a L. speciosum cultivar, under low phytotron temperatures (10, 14, 17°C) and in field experiments. ‘Mount Everest’, ‘Saeki’, ‘Indian Summer’ and ‘White American’ were among the best L. longiflorum cultivars, with less than 20% summer sprouting and good bulb production. This was in contrast to ‘Hinomoto’, ‘Ace’ and some American introductions, which showed more than 60% summer sprouting and low bulb production. The lower the phytotron temperature, the more summer sprouting occurred. The differences observed between the cultivars in the field experiments were in agreement with those observed in the phytotron. The genetic variation proved large enough to start a breeding program for L. longiflorum adapted to cool climate conditions.

Alerations in the development of the main olfactory bulb of the mouse after ethanol exposure

The effect of ethanol on the development of the main olfactory bulb (OB) was examined by light and electron microscopy in 21-day-old Swiss mice (CD-1), exposed to ethanol from embryonic day 13 to postnatal day 21. Two control groups were included in the study to rule out changes due to malnourishment: a normal control group, whose dams were fed rodent lab chow throughout the study and a pairfed group, whose dams were fed the same amount of liquid diet as the dams in the ethanol group but with sucrose replacement of ethanol. Somatic growth, measured by length and body weight, was retarded to the same degree in ethanol and pairfed mice, indicating a similar level of malnourishment in both groups without an additional ethanol effect. The most striking change in olfactory bulb development was the stunted growth of this structure in the ethanol-exposed animals with reductions in the volume of the glomerular. external plexiform and granular cell layers. The laminar organization and cellular cytoarchitecture were not substantially altered by ethanol or malnourishment except for a retarded migration of the periglomerular cells in the ethanol-treated group. Examination of synaptogenesis in the external plexiform layer (EPL) of olfactory bulb from 21-day-old mice in the three groups revealed no treatment-related changes in synaptic structure, appositional length or ratios of the two dominant type of EPL synapses, which are formed between dendrites of the output neurons (mitral and tufted cells) and granule cells. However, morphometric analysis revealed elevated densities of both synaptic types in the ethanol-exposed group but with no change in the total synaptic number per olfactory bulb. The results suggest that ethanol exposure of mice after the latter half of gestation and during the postnatal period primarily affects the growth of the olfactory bulb probably by decreasing neuronal cell growth, and/or proliferation but has little affect on other aspects of maturation such as formation of cortical structure, differentiation and synaptogenesis.

A study of the effect of the environment during growth on sprouting of bulb onions in store

SummaryThe partition of dry matter between leaf and bulb with sheath was studied in relation to the post-harvest physiology of cvs Bola and Robusta grown at three sites for two seasons and dried and stored under standardized conditions. Foliar fall-over was synchronous at all sites in each season but the effects of site showed that crops either partitioned dry matter to the bulb early, lost less fresh weight in drying and sprouted later in store, or partitioned dry matter late, lost more fresh weight in drying and sprouted sooner in store. Crops showing the former behaviour were associated with low rainfall and a high number of day degrees between 6° and 20°C during early growth. There was up to 10 days difference between the sites in 50% sprouting dates. Bulbs of cv Bola sprouted earlier than those of cv Robusta, and bulbs harvested when foliar fall-over was negligible sprouted before those from later harvests. There were no site effects on plant maturity, on bulb growth regulator content (cv Robusta one year only), on sugar content at harvest or during storage, on bulb respiration rates at the end of drying or in the spring, or on bulb weight loss during storage.

生育温度がグラジオラス及びオキザリス (<i>Oxalis bowieana</i> Lodd.) のけん引根及び子球の形成•肥大に及ぼす影響

1. Day/night temperatures of 30/24°C markedly promoted the growth of aboveground parts in both gladiolus and oxalis (Oxalis bowieana Lodd.), and especially in oxalis, continued unfolding of leaves and development of axillary inflorescences were without formation of daughter bulbs. Low temperatures of 17/12°C, however, depressed the growth of aboveground parts, and especially in oxalis, there occurred no increase in the number of leaves and leaf area and no development of inflorescences. While at 24/17°C, the growth was much favoured in both of the aboveground parts and the underground parts. Moreover, when root temperature was controlled independent of air temperature in gladiolus, the growth of aboveground parts was better at lower root temperatures, and such effect of root temperature was greater at the medium than high air temperatures.2. In both gladiolus and oxalis, the number of contractile roots was not affected by air and root temperatures. The elongation and thickening growth of contractile roots, however, were promoted at lower temperatures. The maximal weight of contractile roots and its decrease following contraction were greater in order of low, medium, and high temperatures. Especially in oxalis, there occurred no thickening growth and in gladiolus, not a few contractile roots deteriorated, at the high temperatures of 30/24°C. The formation and thickening growth of daughter corm or bulbs were depressed at higher temperatures, and in oxalis no daughter bulbs were produced. The above-mentioned effects of temperature seemed to be mostly due to the root temperature, at least in gladiolus, according to the experiment in which air and root temperatures were controlled separately.3. The contribution rates of contractile root(s) to the thickining growth of daughter corm or bulbs were calculated as in the previous report (2). In oxalis, the values as high as 56-59% were obtained and they did not vary with growing temperatures. While in gladiolus, they were markedly low and differed with growing temperatures, being comparatively higher at lower temperatures.

グラジオラス及びオキザリス (<i>Oxalis bowieana</i> Lodd.) におけるけん引根の肥大•収縮と子球の肥大について

グラジオラス及びオキザリス (<i>Oxalis bowieana</i> Lodd.) におけるけん引根の肥大•収縮と子球の肥大について

Impaired brain development of the diabetes insipidus Brattleboro rat

The Brattleboro homozygous diabetes insipidus (HOM-DI) mutant rat, incapable of synthesizing the neuropeptide vasopressin, has an impaired body growth of which the severity depends upon the conditions of reproduction. The comparison of homogeneously genotyped litters of HOM-DI and heterozygous (HET-DI) control pups, delivered and nursed by HOM-DI females, was regarded to be the only experimental design that practically excludes other influences on growth differences than the mutation itself. In this breeding scheme the postnatal growth of the HOM-DI brain is impaired, and the weight deficit persists into adulthood. Regionally, the neonatal development of cerebellum and medulla oblongata is most affected, and only slightly that of the cerebral cortex. The other separately isolated parts of the brain seem to be unaffected (olfactory bulbs, hypothalamus, hippocampus, colliculi and thalamus plus basal ganglia). Cerebellum appeared to be the most consistently affected brain area of the HOM-DI Brattleboro rat since, unlike in the case of cerebral cortex and medulla oblongata, the weight deficit persisted throughout life. Olfactory bulb growth, on the other hand, appeared to continue after the first month of life, resulting in an increased weight at day 180. Water content of cerebral cortex and cerebellum of HOM-DI adults appeared slightly higher and might be explained by the generation of different brain water regulation systems for HET- and HOM-DI Brattleboro rats. Protein and DNA estimations of cerebral cortex, cerebellum and olfactory bulbs of male brains during development and in adulthood reflect the differences as found for weight, indicating no obvious changes in cell densities. It is concluded after comparison with other types of brain growth malformations, that the HOM-DI Brattleboro brain has its own particular etiology. The possible involvement of the action of vasopressin is postulated and discussed.

Stimulation of bulb growth in onion (Allium cepa L.) by N,N-diethyl-N-(2-hydroxyethyl)glycine

Both N,N-diethyl-N-(2-hydroxyethyl)glycine (DEHEG) and N,N-diethyl-2-oxomorpholinium chloride (DEOMC) in an optimal dosage of 4 × l0 μmoles per seedling initially accelerated then retarded leaf growth in onion, and doubled the yield of bulbs in field conditions. Gibberellin and auxin nullified the latter effect. It is concluded that DEHEG represents a physiologically active form of DEOMC.

Differentiation in Lilium bulbscales grown in vitro. Effects of activated charcoal, physiological age of bulbs and sucrose concentration on differentiation and scale leaf formation in vitro

AbstractOrgan differentiation and growth of tissue cultured bulbscales of Lilium auratum Lindl. was investigated. Benzyladenine stimulated bulb and bulbscale differentiation but inhibited root formation. Addition of activated charcoal to the medium negated the effect of BA on differentiation, while the growth of bulbs was markedly stimulated. Organ formation was also influenced by the physiological age of bulbs. From bulbscales of a 3‐week‐old bulb, a large number of bulbs and roots was formed but callus was not produced.A high sucrose concentration (90 g/1) reduced the subsequent sprouting after planting in soil. Scale leaf formation was also regulated. Sucrose (30 g/1) stimulated scale leaf formation but 90 g/1 were inhibitory.

Growth and flowering of Nerine flexuosa alba

N. flexuosa alba is a perennial bulbous member of the Amaryllidaceae and an attractive new ornamental. In the bulb, inflorescence buds are formed periodically under any circumstances which allow growth. The problem was that quite often these buds do not elongate, and desiccate prematurely, so that poor flowering results. Light was found not to be a factor in flowering, neither energetically nor photo-periodically, but temperature turned out to be limiting. Good flowering occurred after growth at temperatures of 9 or 13°C, 17 and 21°C being too high. The combination of 9°C during growth and 21°C during storage resulted in 100% satisfactory flowering and an acceptable bulb growth. Gibberellic acid did not effect flowering.

Some aspects of daughter bulb growth and development and apical dominance in bulbous Iris

Apical dominance appears to have minimal direct involvement in daughter bulb formation in the bulbous Iris cultivar Ideal. Daughter bulb number and growth relate to the size and reproductive state of the mother bulb and are not markedly influenced by meristem destruction. In contrast, destruction or removal of the apical meristem promotes lateral bud sprouting in intact bulbs, and lateral bud elongation in Iris meristem explants. These results show that, in contrast to certain other bulbous plants, apical dominance does not direcdy limit daughter bulb number in bulbous Iris, but does prevent lateral bud sprouting.

Increasing bulb growth in onion with growth retardants and reversal of the effect by gibberellin

N,N- diethyl-2- oxomorpholinium chloride (DEOMC) doubled growth of bulbs in Allium cepa whereas (2-chloroethyl)trimethylammonium chloride and tributyl-2,4-dichlorobenzylphosphonium chloride stimulated it around 50%. The effects were nullified by gibberellin. N,N- dimethyl-2- oxomorpholinium chloride and N,N- dimethylmorpholinium chloride were little active as regulators of onion growth.

The Effect of Weeds on the Growth and Development of Narcissus

(1) Competition from weeds in the first growing season hastened foliage senescence and reduced bulb growth in narcissus (cv. Carlton). Weed infestation in the first season also reduced flower production, bulb size and total yield of bulbs in the second growing season, even though the crops were free of weeds in the second season. (2) Weeds had no adverse effect before the crop flowered, but dense weed cover between the end of the flowering period and the onset of normal senescence adversely affected the crop. Weed removal in May or early June avoided crop loss, but removal thereafter merely accelerated crop senescence. (3) Overwintered weeds had most effect on the crop, since their major growth phase paralleled that of the crop. Spring-germinating weeds grew fastest during the final stages of the crop cycle and therefore had less adverse effect, although the crop itself reduced the growth and development of spring-germinating weeds. (4) The results are discussed in relation to ways of improving the efficiency of weed control.

The Levels of Endogenous Cytokinins in Daffodil Bulbs Stored under Different Environmental Conditions

Summary The endogenous cytokinin levels in bulbs of daffodil (Narcissus pseudonarcissus L.) are affected by moisture and temperature. Keeping bulbs in cold moist conditions forces them to grow and also results in a large increase in their cytokinin levels. Most of the cytokinins are present in the roots which develop on the bulbs. It is suggested that the production of these compounds in the roots under cold moist conditions and their subsequent transport to the shoots has a marked effect on bulb growth.

Flower-bud blasting in tulip plants mediated by the hormonal status of the plant

Injection of GA 3, GA 4+7, BA, or kinetin into the flower bud prevented ethylene-induced flower-bud blasting, while injection of water or auxins stimulated the occurrence of the disorder. Single application of GA 4+7 and BA by means of injection into the bulb scales, spraying the shoots or drenching the soil were much less effective or had no effect. Injection of relatively high amounts of BA into the buds caused more than 100 % extra growth of the flower and upper internode; at the same time, the growth of daughter bulbs was reduced and exhaustion of the mother bulb was accelerated. GA 4+7 reduced the duration of the greenhouse period by about 30 %. On the basis of these findings and the enhanced growth of daughter bulbs accompanying flower-bud blasting, we assume that flower-buds compete with daughter bulbs for substrate. The distribution of substrate, which derives mainly from the mother bulb, might be determined by the growth-regulator status of the plant, cytokinins and gibberellins strengthening the sink of the flower-bud and ethylene weakening it.

Effect of Ethephon on Rate of Bulb Enlargement, Maturity, and Yield in Onions1

Abstract Onions (Allium cepa L.) of short and long-day requirements were grown in the field under normal conditions of increasing daylength and treated in the 4, 6, and 10 leaf stages of development with (2-chloroethyl)phosphonic acid (ethephon). Ethephon stimulated bulb enlargement early when applied at the 4 and 6 leaf stages but this enlargement ceased before that of the non-treated plants. Treated plants were short and less prone to lodge at maturity, and yields were reduced by high concentrations and/or repeated applications. Late applications and low concentrations resulted in a pre-harvest increase in the rate of bulb growth.

Effects of olfactory deprivation on postnatal growth of the rat olfactory bulb utilizing a new method for production of neonatal unilateral anosmia

Effects of olfactory deprivation on postnatal growth of the rat olfactory bulb utilizing a new method for production of neonatal unilateral anosmia

Effects of Soil Temperature on Growth and Quality of Onion Bulbs (Allium cepa L.) Used for Dehydration1

Abstract Three cultivars of onions used for dehydration were grown in a greenhouse at constant soil (bulb) temperatures of 13°, 18°, 24°, and 29°C. Growth of tops was best at 24° and poorest at 13°; the number of foliage leaves increased until about the time the bulbs reached half maximum diameter; thereafter the number declined, due to cessation of new foliage leaves and senescence of old leaves. In all plants at 13°, visible bulbing occurred before emergence of the scape. Bulbs matured earliest at 29° but yields were highest at 18° and 24°. The length of bulbs increased with increasing temperature, but the diameters were not significantly different, resulting in very elongated bulbs at high soil temperatures. Soil temperature had no effect on lateral bud formation (doubles). Pungency or votatile propyl sulfur compounds were highly correlated with temperature but percent dry wt, total sugars, and bulb pinking were not correlated.

Influence of Bulb Harvest Date and Temperature on Growth and Flowering of Lilium longiflorum1

Abstract Lilium longiflorum Thunb. cv. Nellie White bulbs were shipped in 1969, 1970, and 1971 from the west coast to St. Paul by air freight from July to October at 15 day intervals. Bulbs were given 0 or 2 weeks of 10°C, 15.5°C or 21 °C followed by 0 or 6 weeks of 4.5°C. Two weeks exposure to 10°C enhanced shoot emergence and flowering of late-harvested non-cooled bulbs and enhanced flowering of cooled bulbs. Treatments of 15.5°C or 21°C had little influence on shoot emergence and flowering of non-cooled bulbs and delayed flowering of early harvested cooled bulbs. With time and with increased bulb growth the degree of dormancy (delay of emergence) decreased and degree of maturity (enhancement of early flowering by 4.5°) increased.