Allongement et morphologie de pousses annuelles issues de greffe chez le noyer commun, Juglans regia L. cv. Lara (Juglandaceae)

2000 ◽  
Vol 77 (11) ◽  
pp. 1595-1603
Author(s):  
Sylvie Sabatier ◽  
Daniel Barthélémy ◽  
Isabelle Ducousso ◽  
Eric Germain

Extension growth, number of internodes of the main stem, and sylleptic branches were recorded weekly during the 1994 growing season on 1-year-old Juglans regia L. cv. Lara scions. Date of sylleptic branch production and branch position on the main stem were also recorded. Two main stem types were distinguished according to their growth pattern: continuous or rhythmic over one growing season. Three sylleptic branch types were distinguished in relation with their growth pattern and morphology: (i) long shoots elongated in two growth flushes that showed a zone of short internodes above the first internode or hypopodium, (ii) long shoots elongated in one flush only with long internodes above the hypopodium, and (iii) short shoots corresponding with the elongated hypopodium only. Each type of sylleptic shoot is generally produced at a different growth period. Main stems developed sylleptic branches when their growth rate was higher than 17 cm/week. On the median part of the main stem, sylleptic long shoots were distributed according to a basipetal gradient of increasing vigour (extension duration, length, and number of internodes). Sylleptic short shoots were generally localized above long shoots.

1988 ◽  
Vol 18 (2) ◽  
pp. 188-194 ◽  
Author(s):  
Roberto Calamassi ◽  
Mauro Falusi ◽  
Laura Mugnai

The process of primary growth in 2-year-old seedlings of six Pinusbrutia Ten. provenances is described. At the end of the first growing season, two types of shoot morphology were observed: type 1, a terminal winter bud, and type 2, a terminal rosette of primary needles protecting the meristematic apex. During the 2nd year the seedlings exhibited a succession of shoots (varying in number from one to five), each of which was due to the elongation of a new apical bud. Morphological observations along with an anatomical examination of the winter bud led to the conclusion that the growth pattern in juvenile P. brutia is monocyclic with a variable number of summer shoots (using the terminology proposed by Lanner (Lanner, R.M. 1976. In Tree physiology and yield improvement. Editedby M.G.R. Cannell and F.T. Last. Academic Press, London, pp. 223-243)). The provenances studied differed both in growth potential and in seasonal growth pattern (differences in number of shoots, ratio of spring shoot to total growth, growth rate). Two groups could be identified: (i) the provenances of the island of Crete, which had a low growth potential and short growing season, and (ii) the high-altitude provenances of inland Turkey, with high growth potential and a growth rate that peaked in summer.


In Betula pendula buds are produced on long and on short shoots. The long shoots bear many daughter buds on elongated internodes and they con­tribute overwhelmingly to the increase in the size of the tree and to its architecture. Short shoots normally bear only one bud and at best only replace themselves each year in the shoot population. Individual trees were grown close together in groups of three so that each experienced interference from neighbours on one side and not on the other. A lower proportion of buds in the high-interference zone developed into long shoots in the second and third years of the three-year experiment and a lower proportion survived to the end of the growing season in year 2. The overall proportion of buds that died was greater in the high-interference zone. The influence of neighbours became more marked as branches aged and were overtopped in the canopy. This led to asymmetry in the form of the trees. The different sides of a single tree in this study may approach the form of an open-grown individual on one side and that of a forest tree on the other.


1984 ◽  
Vol 62 (9) ◽  
pp. 1904-1915 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell

The upper 5 years of crown growth in samples of Larix laricina (Du Roi) K. Koch (tamarack) saplings from natural populations in the Fredericton, N.B., area provided data to model architectural relationships describing patterns of (nonsylleptic) order 1 branching in relation to development of the main stem. The model was based on relationships between branch extension and height growth, and numbers and positions of order 1 branches. Elevation angles of shoots making up the branches, and conversion of order 1 long shoots to order 1 short shoots were also incorporated. Lengths of current shoots of major order 1 branches tended to decrease with increasing depth in the crown. Similar tendencies occurred among lengths of all current branch extensions within single height-growth increments, but the decreases in length became less regular with increasing age of branch. Because the relationships were complex, alternative approaches to modelling shoot lengths were adopted to enhance understanding of the patterns involved. Deterministic and stochastic elements were used in the overall model to account for significant proportions of morphological variability. Simulations based on the alternatives within the model were realistic in their interpretations of actual sapling crown architecture. Classification of L. laricina according to previously proposed architectural models that qualitatively describe general development was discussed.


1980 ◽  
Vol 10 (3) ◽  
pp. 316-326 ◽  
Author(s):  
Robert A. Gregory

Cytohistology and the development and morphogenesis of sugar maple (Acersaccharum Marsh.) shoots were studied. Three types were recognized: short shoots, long shoots entirely preformed in the bud (Epf long), and long shoots partially preformed in the bud (heterophyllous). The three shoot types varied not only in the size and number of internodes and leaves but also in the development of terminal buds. Terminal bud formation was delayed in heterophyllous shoots but because of a shorter plastochron, which extended later into the growing season, the terminal apices of these shoots were able to annually produce more primordia than in other shoot types. The beginning of embryonic shoot formation, however, began about the same time (late July) for all shoot types.


1993 ◽  
Vol 324 ◽  
Author(s):  
C. Pickering ◽  
D.A.O. Hope ◽  
W.Y. Leong ◽  
D.J. Robbins ◽  
R. Greef

AbstractIn-situ dual-wavelength ellipsometry and laser light scattering have been used to monitor growth of Si/Si1−x,Gex heterojunction bipolar transistor and multi-quantum well (MQW) structures. The growth rate of B-doped Si0 8Ge0.2 has been shown to be linear, but that of As-doped Si is non-linear, decreasing with time. Refractive index data have been obtained at the growth temperature for x = 0.15, 0.20, 0.25. Interface regions ∼ 6-20Å thickness have been detected at hetero-interfaces and during interrupted alloy growth. Period-to-period repeatability of MQW structures has been shown to be ±lML.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petra G. Šimková ◽  
Gerhard W. Weber ◽  
Fernando V. Ramirez Rozzi ◽  
Lotfi Slimani ◽  
Jérémy Sadoine ◽  
...  

AbstractThe Baka Pygmies are known for their short stature resulting from a reduced growth rate during infancy. They are peculiar also for their teeth erupt earlier than in any other African population, and their posterior dentition is larger than in non-Pygmy populations. However, the Baka’s dental morphology, like several other aspects of their biology, is still understudied. Here, we explore the variation of the Baka’s deciduous upper and lower second molars (dm2s) in comparison to a geographically heterogeneous human sample by means of 3D geometric morphometrics and analysis of dental traits. Our results show that the different populations largely overlap based on the shape of their dm2s, especially the lower ones. Their distal region and the height of the dentinal crown differ the most, with the Baka showing the most extreme range of variation. Upper and lower dm2s covary to a great extent (RV = 0.82). The Baka’s and South Americans’ dm2s were confirmed among the largest in our sample. Despite the Baka’s unique growth pattern, long-lasting isolation, and extreme dental variation, it is not possible to distinguish them from other populations based on their dm2s’ morphology only.


1967 ◽  
Vol 45 (9) ◽  
pp. 1643-1651 ◽  
Author(s):  
J. Johanna Clausen ◽  
T. T. Kozlowski

Tamarack (Larix laricina (DuRoi) K. Koch) produces long shoots which bear two kinds of needles. Early needles are present in the bud and elongate rapidly after budbreak. Late needles, few of which are present in the bud, elongate later than early needles. Short shoots bear early needles only, and stem length seldom exceeds 1 mm. Seasonal changes in length and weight of needles and stems of both shoot types were measured. In long shoots, 75% of stem elongation, more than 70% of stem weight increment, and 65–70% of late needle elongation occurred after early needles were full-sized. Stem and late needle elongation ceased simultaneously, after which time needle weight decreased and stem weight increased. Early needles probably drew on food reserves while developing, and then themselves contributed to stem and late needle elongation. Final stem weight increase probably used photosynthate from both late and early needles of the current year.Shading of current and last year's needles showed that shoots in which photosynthesis was interrupted in this way produced shorter, lighter-weight stems than did control shoots.


1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.


1977 ◽  
Vol 34 (10) ◽  
pp. 1774-1783 ◽  
Author(s):  
Lloyd L. Smith Jr.

In an investigation of the commercial fishery of Red Lakes, Minnesota, for the 46-yr period 1930–75, catch statistics were analyzed, and the dynamics of the perch and walleye populations were examined. Mean annual yields of walleye for two statistical periods, 1930–53 and 1954–75, were 309,900 and 245,100 kg, respectively for walleyes, and 96,400 and 109,500 kg for perch. Annual abundance (CPE based on average catches per day per 5-net units of gill nets) varied from 3.8 to 64.6 kg for walleye, and from 2.5 to 34.4 kg for perch. Causes of fluctuations in harvestable stock were directly related to strength of year-classes and to growth rate during the season of capture. Year-class strength was not related to the abundance of parent stock or of potential predators. The respective strengths of year-classes of perch and walleye in the same year were positively correlated (r = 0.859, P < 0.01), and are directly related to climatic factors. Growth rate of walleye in different calendar years varied from +30.7 to −42.2% of mean growth, and that of perch from +13.4 to −8.6% (1941–56). Growing season began in mid-June and was almost over by September 1. Walleye yield could be enhanced by starting harvest July 1 instead of early June. Perch yield could be improved by harvesting small perch. Key words: Percidae, Perca, population dynamics, Stizostedion, long-term yield


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