Sympodial Branching
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Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to as a sympode or pseudaxis, is the primary shoot, comprising the stronger branches, formed during sympodial growth. The pattern is similar to
dichotomous branching This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...
; it is characterized by branching along stems or hyphae. In
botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...
, sympodial growth occurs when the apical
meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...
is terminated and growth is continued by one or more lateral meristems, which repeat the process. The apical meristem may be consumed to make an
inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...
or other determinate structure, or it may be aborted.


Types

If the sympodium is always formed on the same side of the branch bifurcation, e.g. always on the right side, the branching structure is called a helicoid cyme or bostryx. If the sympodium occurs alternately, e.g. on the right and then the left, the branching pattern is called a scorpioid cyme or cincinus (also spelled cincinnus). Leader displacement may result: the stem appears to be continuous, but is in fact derived from the meristems of multiple lateral branches, rather than a
monopodial Vascular plants with monopodial growth habits grow upward from a single point. They add leaves to the apex each year and the stem grows longer accordingly. The word ''Monopodial'' is derived from Greek "mono-", ''one'' and "podial", "foot", in refe ...
plant whose stems derive from one meristem only.Simpson, M. G. 2006. ''Plant Systematics.'' Elsevier Academic Press. Pg. 355. Dichotomous substitution may result: two equal laterals continue the main growth.


In orchids

In some
orchids Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...
, the apical meristem of the
rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...
forms an ascendent swollen stem called a
pseudobulb The pseudobulb is a storage organ found in many epiphytic and terrestrial sympodial orchids. It is derived from a thickening of the part of a stem between leaf nodes and may be composed of just one internode or several, termed heteroblastic and ...
, and the apical meristem is consumed in a terminal inflorescence. Continued growth occurs in the rhizome, where a lateral meristem takes over to form another pseudobulb and repeat the process. This process is evident in the jointed appearance of the rhizome, where each segment is the product of an individual meristem, but the sympodial nature of a stem is not always clearly visible.


References

{{Reflist Plant morphology Orchid morphology