Shoot development in Betula papyrifera. III. Long-shoot organogenesis

1984 ◽  
Vol 62 (3) ◽  
pp. 437-445 ◽  
Author(s):  
Alastair D. Macdonald ◽  
D. H. Mothersill ◽  
J. C. Caesar
Keyword(s):  
Shoot Organogenesis ◽  
Bud Break ◽  
Betula Papyrifera ◽  
Mature Trees ◽  
Leaf Production ◽  
Shoot Bud ◽  
Growing Seasons ◽  
Male Inflorescence ◽  
Axillant Leaf ◽  
Photosynthetic Potential

Buds and developing branches of Betula papyrifera were collected weekly from mature trees during three successive growing seasons. Material was prepared to show stages of bud inception, development, flushing, shoot expansion, and male inflorescence inception and early development. Stages of bud development were correlated with axillant leaf and subjacent internodal extension. Long-shoot buds develop in the axils of distal late leaves of the previous season's long shoot. The bud contains one rudimentary leaf with prominent stipules, two or three embryonic foliage leaves which flush as early leaves, and about five smaller primordia which expand in the spring as late leaves. Preformed primordia are produced in mid-May through to early August. A pause in the inception sequence occurs in June, corresponding to the period of rapid late-leaf and internodal expansion of axillant leaves and subjacent internodes. Long-shoot bud determination occurs in mid-July. True late leaves may form during shoot extension. Male inflorescence induction, which occurs before bud break, restricts late leaf production and results in the last-formed leaf primordia maturing as transitional leaves instead of foliage leaves. Male induction limits crown expansion by reducing sites for axillary bud formation. This reduces the photosynthetic potential of the shoot.

Shoot development in Betula papyrifera. VI. Development of the reproductive structures

1987 ◽  
Vol 65 (3) ◽  
pp. 466-475 ◽  
Author(s):  
Alastair D. Macdonald ◽  
D. H. Mothersill
Keyword(s):  
Male Flower ◽  
Female Flower ◽  
Bud Burst ◽  
Betula Papyrifera ◽  
Short Shoot ◽  
Mature Trees ◽  
Male And Female ◽  
Shoot Bud ◽  
Growing Seasons ◽  
Northwestern Ontario

Reproductive buds and developing inflorescences were collected weekly from mature trees during three successive growing seasons in northwestern Ontario. Material was prepared to show all stages of inflorescence and flower development and meiosis. Male inflorescence induction, involving the long-shoot bud apex and one or two proximal axillary apices, occurred in early May, before bud burst. Female induction involved the short-shoot bud apex and occurred in late June – early July. Both male and female partial inflorescences resembled a simple dichasium. The male flower consisted of usually two stamens and two or three tepals variably arranged. Meiosis occurred in late July – early August. Each female flower consisted of two stigmas, two connate tepals that were not noticeable at maturity, and a parietal placenta bearing two unitegmic ovules. Meiosis occurred in mid-June, after pollination in mid-May. It is concluded that developmental data do not help elucidate whether the inferior portion of the gynoecial wall is cauline or appendicular and whether the placenta is derived from axial or carpellary tissue. It is suggested that the trigger(s) evoking male and female inflorescence induction may be different and that the metabolic prerequisites for induction and early development would be supplied by winter-stored material for male development and by current metabolic processes for female development.

Birch foliar responses to simulated acidic fog and Septoria betulae inoculations

2001 ◽  
Vol 31 (3) ◽  
pp. 392-400
Author(s):  
K B Kouterick ◽  
J M Skelly ◽  
S P Pennypacker ◽  
R M Cox
Keyword(s):  
Bay Of Fundy ◽  
Betula Papyrifera ◽  
Mature Trees ◽  
The Past ◽  
Foliar Symptoms ◽  
Foliar Symptom ◽  
Foliar Senescence ◽  
Symptomatic Leaf ◽  
Acidic Fog ◽  
Ph Level

The effects of simulated acidic fog and inoculation with Septoria betulae Pass. on foliar symptom development and foliar senescence of Betula papyrifera Marsh. and Betula cordifolia Regel seedlings were investigated in 1997 and 1998 under greenhouse conditions. An interactive role may exist between acidic fog events and S. betulae in causing birch foliar browning, a disease reported over the past decade to occur on mature trees growing adjacent to the Bay of Fundy, Canada. Seedlings received applications of simulated fog adjusted to pH 3.2, 4.2, and 5.6 or a no-fog treatment. Inoculation treatments at each fog pH level were accomplished through spray atomization with S. betulae conidial suspensions and by placing naturally infected birch leaves bearing pycnidia of the fungus on plastic nets suspended above seedlings in enclosed chambers. Percent symptomatic leaf area of seedlings inoculated with S. betulae was nearly double that recorded for non-inoculated seedlings. Foliar browning resembled symptoms observed on mature trees in the field. Foliar symptoms were observed on non-inoculated seedlings, with greater severities associated with seedlings exposed to the most acidic fog treatment. Leaf senescence was also greatest for spray-inoculated leaves that had been exposed to the pH 3.2 fog treatment. Pycnidial development was not influenced by the pH of the fog treatments but was greater in all fog treatments than in no-fog treatments. Although both acidic fog and S. betulae infection are able to cause symptoms independently, the data suggest that an interactive role may exist in causing birch foliar browning. However, to obtain the same severity of foliar browning as observed on natural forest-grown trees in the Bay of Fundy region, S. betulae must be present.

Distribution of the eucalypt-defoliating sawfly Perga affinis affinis (Hymenoptera)

1965 ◽  
Vol 13 (4) ◽  
pp. 593 ◽  
Author(s):  
PB Carne
Keyword(s):  
Field Experiments ◽  
Climatic Factors ◽  
Leaf Shape ◽  
Mature Trees ◽  
Leaf Production ◽  
Study Region ◽  
Sawfly Larvae ◽  
Litter Accumulation ◽  
Large Trees ◽  
Individual Trees

The distribution of the sawfly is discussed at several levels, ranging from that within a study region which comprised a substantial proportion of the known range of the insect, to that within the crowns of individual trees. A mosaic of areas was recognized within the region, each characterized by a degree of ecological uniformity and in which saivfly populations maintained relatively high or low levels of abundance during 6 yr of observation. The distribution of the insect is influenced strongly by climatic factors, the rainfall and temperature statistics for the critical period October-March for all areas in which it occurs being closely grouped. Such grouping is even more marked for those areas in which the sawfly was consistently most abundant. The cool wet limit of the sawfly's distribution coincides with that of a favoured host species, but the hot dry limit appears to be determined by the insect's susceptibility to desiccation. Although many naturally occurring and planted eucalypts will support sawfly larvae, persistent infestations were recorded only where one or more of three species grew - Eucalyptus blakelyi, E. camaldulensis, or E. melliodora. The sawfly is an inhabitant of river valley woodland, rarely becoming abundant in other situations and being absent from sclerophyll forest formations. Survival of the insect is greatly influenced by the ease with which it can penetrate into the soil for cocoon formation; it tends to be most abundant in areas of light soil, or where large trees provide a deep litter accumulation. The susceptibility of trees to infestation is influenced by seasonal production of new foliage. Those growing in sites where the water table is high, and whose leaf production is to a large extent independent of rainfall patterns, may be subject to chronic attack. Distribution between trees is affected by their leaf shape and texture, and by their history of previous defoliation. Small trees are particularly prone to attack, and infestation of mature trees is generally an indication of outbreak abundance of the insect. Similarly, marginally favoured species are attacked only when oviposition sites on more favoured trees are virtually saturated. Field experiments indicated that an observed contagious distribution of sawfly eggs in portions of the crowns of individual trees is not the result of overt gregariousness on the part of the females, but results from the attraction of the latter to foliage of certain physical characteristics and position on the tree.

REGENERATION OF TREMA ORIENTALIS (BLUME) LINN.: EFFECT OF GROWTH REGULATORS, CULTURE CONDITIONS, AND AGE AND SOURCE OF EXPLANTS

1995 ◽  
Vol 43 (4) ◽  
pp. 391-395 ◽  
Author(s):  
G.R. Rout ◽  
S. Samantaray ◽  
P. Das
Keyword(s):  
Growth Regulators ◽  
Leaf Explants ◽  
Naphthaleneacetic Acid ◽  
Mature Trees ◽  
Regeneration Rate ◽  
Bud Regeneration ◽  
Shoot Bud ◽  
Shoot Bud Regeneration ◽  
Trema Orientalis

Optimal conditions for high frequency shoot bud regeneration from leaf callus of Trema orientalis (Blume) Linn. were studied. The regeneration rate was controlled by the growth regulators, the age and the source of the explants, and the illumination conditions. Irrespective of illumination conditions, shoot bud regeneration was achieved only in media containing benzyladenine (BA) + α-naphthaleneacetic acid (NAA) combinations, with the best results being obtained in the presence of 2.5 mg/1 BA and 0.25–0.5 mg/1 NAA. The morphogenic response was less frequent in the calluses derived from leaf explants of the mature trees compared to those of the in vitro-grown seedlings. The rate of shoot bud regeneration was more pronounced in the cultures maintained for 4 weeks in the light (16-h photoperiod) than the cultures incubated in the dark. Regenerated shoots were rooted on the medium containing 1/2 strength basal Murashige and Skoog (MS) salts supplemented with 0.01 mg/1 NAA or indole-3-butyric acid (IBA). The rooted plantlets were established in the greenhouse.

Shoot development in Betula papyrifera. I. Short-shoot organogenesis

1983 ◽  
Vol 61 (12) ◽  
pp. 3049-3065 ◽  
Author(s):  
Alastair D. Macdonald ◽  
D. H. Mothersill
Keyword(s):  
Axillary Buds ◽  
Axillary Bud ◽  
Bud Burst ◽  
Betula Papyrifera ◽  
Short Shoot ◽  
Mature Trees ◽  
Shoot Buds ◽  
Female Inflorescence ◽  
Terminal Bud ◽  
Short Shoots

Buds and developing branches of Betula papyrifera were collected weekly from mature trees during three successive growing seasons. Material was prepared to show stages of bud inception, development, and flushing and female inflorescence inception. Short shoots develop from (i) proximal axillary buds on long shoots (ii) short-shoot terminal buds, or (iii) axillary buds on flowering short shoots. An axillary bud apex forms a terminal bud after bud burst. An axillary bud possesses one outer rudimentary leaf, but all other short-shoot buds have three outer rudimentary leaves. All short-shoot buds possess, in addition, one–three embryonic foliage leaves and, distally, three primordial rudimentary leaves which form the outermost appendages of the succeeding terminal bud. Rudimentary leaf stipules form the cataphylls. Foliage leaf primordia are initiated in May – early June and rudimentary leaves arise in late June – July. If a bud apex is initiated in year n, female inflorescence induction occurs in late June of year n + 1 or any succeeding year. An axillary bud develops on a short shoot as a consequence of flowering; it is initiated concurrently with inflorescence development and its development is completed during flowering and seed maturation. Short- and long-shoot buds can be distinguished, upon dissection, in mid-July when buds are forming. Hence, determination of potential long and short shoots occurs the year before bud burst.

Cloudiness regulates gross primary productivity of a poplar plantation under different environmental conditions

2017 ◽  
Vol 47 (5) ◽  
pp. 648-658 ◽  
Author(s):  
Hang Xu ◽  
Zhiqiang Zhang ◽  
Jiquan Chen ◽  
Mengxun Zhu ◽  
Manchun Kang
Keyword(s):  
Primary Productivity ◽  
Forest Ecosystems ◽  
Northern China ◽  
Gross Primary Productivity ◽  
Poplar Plantation ◽  
Radiation Component ◽  
Growing Seasons ◽  
Photosynthetic Productivity ◽  
Photosynthetic Potential ◽  
Lower Vapor Pressure

Cloud cover regulates the gross primary productivity (GPP) of forest ecosystems by changing the radiation component and other environmental factors. In this study, we used an open-path eddy covariance system and microclimate sensors installed over a poplar plantation in northern China to measure the carbon exchange and climate variables during the mid-growing seasons (June to August) in 2014 and 2015. The results indicated that the GPP of the plantation peaked when the clearness index (CI) was between 0.45 and 0.65, at which point diffuse photosynthetically active radiation (PARdif) had reached its maximum. Cloudy skies increased the maximum ecosystem photosynthetic capacity (Pmax) by 28% compared with clear skies. PARdif and soil moisture were the most and the least crucial drivers for photosynthetic productivity of the plantation under cloudy skies, respectively. The ecosystem photosynthetic potential was higher under lower vapor pressure deficit (VPD < 1.5 kPa), lower air temperature (Ta < 30 °C), and nonstressed conditions (REW > 0.4) for cloudy skies due to effects of Ta and VPD on stoma. Overall, our research highlighted the importance of cloud-induced radiation component change and environmental variation in quantifying the GPP of forest ecosystems.

Ontogenetic changes in leaf phenology of a canopy species, Elateriospermum tapos (Euphorbiaceae), in a Malaysian rain forest

2002 ◽  
Vol 18 (1) ◽  
pp. 91-105 ◽  
Author(s):  
NORIYUKI OSADA ◽  
HIROSHI TAKEDA ◽  
AKIO FURUKAWA ◽  
MUHAMAD AWANG
Keyword(s):  
Rain Forest ◽  
Meteorological Factors ◽  
Light Availability ◽  
Leaf Phenology ◽  
Leaf Fall ◽  
Ontogenetic Changes ◽  
Mature Trees ◽  
Leaf Production ◽  
Leaf Emergence ◽  
Canopy Species

Leaf phenology was studied in individuals of a canopy species, Elateriospermum tapos (Euphorbiaceae), at various ontogenetic stages, in a Malaysian rain forest. The timing of leaf emergence was not synchronized among sapling individuals, and was not correlated with any meteorological factors of the preceding month. The timing of leaf fall in saplings was positively correlated with net radiation, and maximum and minimum temperature, but negatively correlated with relative humidity the preceding month, although these correlations were weak. The leaf production rate was larger under higher light, but the leaf fall rate was not related to the light regime of the saplings. Thus, leaf production was enhanced by the light availability for each individual, while leaf fall may have been enhanced by drought stress. Non-synchronous leaf production appears to be important for sapling growth, allowing saplings to occupy better-lit space quickly. On the other hand, tall trees showed a clear synchronous leaf-fall pattern, with an annual cycle, and no meteorological factors were correlated with the timing of leaf fall. Mature trees of this species produced flowers simultaneously with new leaves, after shedding their leaves. This suggests that the need to synchronize flowering might be the primary determinant of leaf production phenology in mature individuals.

scholarly journals Impacts of experimental defoliation on native and invasive saplings: are native species more resilient to canopy disturbance?

2020 ◽  
Vol 40 (7) ◽  
pp. 969-979
Author(s):  
Elise D Hinman ◽  
Jason D Fridley
Keyword(s):  
Invasive Species ◽  
North America ◽  
Native Species ◽  
Radial Growth ◽  
Survival Rates ◽  
Growth Strategy ◽  
Extreme Weather Events ◽  
Leaf Production ◽  
Growing Seasons ◽  
Light Gradient

Abstract Many non-native, invasive woody species in mesic forests of North America are both shade tolerant and more productive than their native counterparts, but their ability to tolerate disturbances remains unclear. In particular, complete defoliation associated with herbivory and extreme weather events may have larger impacts on invaders if natives maintain greater resource reserves to support regrowth. On the other hand, invaders may be more resilient to partial defoliation by means of upregulation of photosynthesis or may be better able to take advantage of canopy gaps to support refoliation. Across a light gradient, we measured radial growth, new leaf production, non-structural carbohydrates (NSCs), chlorophyll content and survival in response to varying levels of defoliation in saplings of two native and two invasive species that commonly co-occur in deciduous forests of Eastern North America. Individuals were subjected to one of the four leaf removal treatments: no-defoliation controls, 50% defoliation over three growing seasons, 100% defoliation over one growing season and 100% defoliation over two growing seasons. Contrary to our hypothesis, native and invasive species generally did not differ in defoliation responses, although invasive species experienced more pronounced decreases in leaf chlorophyll following full defoliation and native species’ survival was more dependent on light availability. Radial growth progressively decreased with increasing defoliation intensity, and refoliation mass was largely a function of sapling size. Survival rates for half-defoliated saplings did not differ from controls (90% of saplings survived), but survival rates in fully defoliated individuals over one and two growing seasons were reduced to 45 and 15%, respectively. Surviving defoliated saplings generally maintained control NSC concentrations. Under high light, chlorophyll concentrations were higher in half-defoliated saplings compared with controls, which may suggest photosynthetic upregulation. Our results indicate that native and invasive species respond similarly to defoliation, despite the generally faster growth strategy of invaders.

SHOOT GROWTH CHARACTERISTICS OF HETEROPHYLLOUS WOODY PLANTS

1966 ◽  
Vol 44 (6) ◽  
pp. 827-843 ◽  
Author(s):  
T. T. Kozlowski ◽  
J. Johanna Clausen
Keyword(s):  
Populus Tremuloides ◽  
Woody Plants ◽  
Shoot Growth ◽  
Shoot Elongation ◽  
Growth Characteristics ◽  
Leaf Primordia ◽  
Bud Break ◽  
Betula Papyrifera ◽  
Long Shoots ◽  
Winter Buds

Observations were made on relationships between contents of winter buds and subsequent shoot growth characteristics of Betula papyrifera, B. alleghaniensis, Populus tremuloides, and P. grandidentata. In both species of Betula, winter buds expected to produce long shoots contained both embryonic leaves and leaf primordia. Both early and late leaves were produced by growing shoots. In contrast, in both species of Populus all leaves produced on the observed shoots appeared at bud break and matured rapidly. Evidence for a variety of patterns and degrees of dependency of expanding shoot systems on reserve foods and currently produced carbohydrates is presented. Shoot elongation of species with shoots fully preformed in the winter bud utilizes large amounts of reserve carbohydrates. In growth of long shoots of heterophyllous species considerable current photosynthate appears to be used. In Betula the contribution of early and late leaves to shoot growth differed markedly. Covering of early leaves before mid-June inhibited shoot growth. The presence of normally growing early leaves was essential for normal shoot development and survival.

Tree shoot elongation in northern Wisconsin and relationships with temperature and precipitation

1976 ◽  
Vol 6 (4) ◽  
pp. 487-498
Author(s):  
Richard R. Buech
Keyword(s):  
Shoot Elongation ◽  
Total Elongation ◽  
Forest Community ◽  
Mature Trees ◽  
Growing Seasons ◽  
Temperature And Precipitation

The relative amount of shoot elongation in the upper crowns of mature trees was studied in a forest community near Rhinelander, Wisconsin. Curves of the percentage of total elongation for the 1970 through 1973 growing seasons were similar to those previously reported for younger trees, but the elongation periods were generally shorter. Quercusrubra had the shortest period of elongation, followed by Acersaccharum. Tiliaamericana, Acerrubrum, Betulapapyrifera, Populustremuloides, and Abiesbalsamea in order of increasing duration. Comparisons were also made of the elongation patterns among species and years. Expected dates for the attainment of 10% elongation based on heat sums and year-day were compared with the observed dates. For all species except A. balsamea and A. saccharum, the comparison demonstrated the use of heat sums in predicting initial elongation.

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