Sympodium


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sympodium

[sim′pōd·ē·əm]
(botany)
A branching system in trees in which the main axis is composed of successive secondary branches, each representing the dominant fork of a dichotomy.

Sympodium

 

the axial organ of a plant (root or stem), consisting of successive secondary axes and arising as a result of topping during growth and branching.

With dichotomous branching, which characterizes lower plants and a number of higher sporebearing plants (for example club mosses), the sympodium arises as a result of the more intensive growth of one of the bifurcated branches and the sideward displacement of the branch at each of the repeated stages of branching. In lateral branching, which is a feature of most higher plants (including all flowering plants), the sympodium forms as a result of the cessation of top growth of the root or the shoot; a lateral root or shoot arises that generally grows in the same direction as the displaced element. Curtailment of activity at the tip of the meristem can be caused by death resulting from external damage (desiccation, freezing, cutting), by the formation of an apical flower or inflorescence that includes the entire tip of the meristem, or by the deflection of the main axis away from the original growth direction.

The trunks and large branches of most hardwood trees and shrubs are typical sympodia, as are the rhizomes of most perennial herbs. Topping occurs in these organs many times, sometimes as often as once a year. Inflorescences that are formed according to the same principle as sympodia are called cymose. The sympodium is most clearly seen in monochasia.

T. I. SEREBRIAKOVA

References in periodicals archive ?
While a few isolated comments suggested that some students preferred the traditional use of a "blackboard and chalk", most students were perfectly fine with the inclusion of a distance section and with the instructor using a Sympodium.
Pettigrew (1994) reported that fruit removal from a sympodium increased boll retention at the remaining FS, either FS 1 or 2.
In addition, the fate of neighboring bolls at all FS on each sympodium was recorded.
Competition from only one additional boll on a sympodium was designated by a 2 or 3 as follows.
The obvious preference for a given sympodium was to retain only one boll at FS 1, demonstrated by the fact that percentage retention of solitary bolls at FS 1 was about the same as the combined total retention for Competition Levels 2 and 3 (Fig.
In fact, under natural conditions of bud and boll retention, distal bolls on a sympodium would not be expected to greatly affect retention at FS 1 because bolls at FS 1 are [approximately equal to] 6 and 12 d older than bolls at FS 2 and 3, respectively (Jenkins et al.
With a boll, FS 1 is a reproductive sink that can compete successfully for assimilates with distal FS on the same sympodium and, lacking a boll, may result in additional assimilate availability to FS 2.
Despite the findings by Peoples and Matthews (1981) that assimilates remain in a sympodium unless all bolls are aborted, there was little evidence from these results that the absence of bolls at FS 1 and 2 increased boll retention at FS 3.
The least amount of seedcotton was produced from bolls at FS 1 when it was the only boll on a sympodium and, contrary to findings reported from other experiments in which fruit was artificially removed (Pettigrew, 1994; Heitholt, 1997), the greatest boll weight at FS 1 occurred when bolls were retained at FS 2 or at both FS 2 and 3 (Fig.
Excellent source conditions may have simultaneously benefited all FS on the sympodium increasing the overall productivity of the branch.
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The Sympodium ID250 interactive pen display features a sleek, slim design, 15" LCD screen, superior interactivity and improved ease-of-use at a lower price -- almost 40 percent less than previous models.