The main difference between acropetal and basipetal is that acropetal is the development, maturation or opening, in sequence, from the base towards the apex, whereas the basipetal is the development, maturation or opening from the apex towards the base in the sequence.
Acropetal and basipetal are two terms used to describe different arrangements of florets in the inflorescence. The older parts are at the bottom in the acropetal arrangement while the older parts are on the top in the basipetal arrangement.
Key Areas Covered
1. What is Acropetal Arrangement
– Definition, Structure, Importance
2. What is Basipetal Arrangement
– Definition, Structure, Importance
3. What are the Similarities Between Acropetal and Basipetal Arrangement
– Outline of Common Features
4. What is the Difference Between Acropetal and Basipetal Arrangement
– Comparison of Key Differences
Key Terms
Acropetal, Basipetal, Cymose, Flower Arrangements, Inflorescence, Racemoce
What is Acropetal Arrangement
The acropetal arrangement is a type of development of florets in an inflorescence starting from the base towards the apex. Therefore, this type of development occurs in an upward direction. Furthermore, as it contains a continuously developing peduncle, or an apex, of the main stem, the acropetal development can be considered as a type of indefinite growth. Also, as the first floret opens at the base of the peduncle while the apex of the peduncle is still growing. Hence, the formation of flowers in the acropetal arrangement is indefinite.
Figure 1: Acropetal Development in Asian Tick Trefoil
Furthermore, the acropetal arrangement is a type of racemose inflorescence, which is an indeterminate inflorescence. Also, the growth of peduncle in acropetal development is monopodial. That means; the upwards growth of the peduncle starts from a single point. Additionally, the formation of flowers in this arrangement is centripetal means the younger florets occur towards the centre while the old ones occur towards the outside. Therefore, the formation of the fruits also occurs, starting from the base.
What is Basipetal Arrangement
The basipetal arrangement is another type of development of florets in an inflorescence, starting from the apex towards the base. Therefore, it is a type of development that occurs in a downward direction. Here, the first floret opens at the apex of the peduncle and further developing of florets occurs towards the base. So, the growth of the peduncle is restricted by the formation of a floret at the beginning. Thereby, it is a type of definite growth, and basipetal arrangements have a peduncle with determinate growth. On that account, the formation of florets in the inflorescence becomes definite as well.
Figure 2: Basipetal Development in Geraniums
Moreover, the basipetal arrangement is a type of cymose inflorescence. Also, it has either a sympodial or mutlipodial peduncle. That means; other lateral meristems become activated in addition to the main apical meristem, which develops the main peduncle, forming several sub-peduncles. It occurs due to the termination of the apical meristem by the formation of the first floret at the apex. However, basipetal development shows a centrifugal floret development. Therefore, the young florets occur at the periphery surrounding the older ones, sometimes the newly-forming fruits.
Similarities Between Acropetal and Basipetal Arrangement
- Acropetal and basipetal are two types of floret arrangements in different types of inflorescences.
- Their development is described based on the base and the apex of the peduncle, the main stem of the inflorescence.
- Besides, both enhance cross-pollination.
Difference Between Acropetal and Basipetal Arrangement
Definition
Acropetal refers to the development or maturation of anatomical parts from the base upward towards the apex, while basipetal refers to the development or maturation from the apex downward towards the base.
Direction of Development
The development of the acropetal parts occurs upwards from the base or point of attachment, while the development of the basipetal parts occurs downwards towards the base or point of attachment. Thus, this is the main difference between acropetal and basipetal arrangement.
The Occurrence of the Older Parts in the Arrangement
Another difference between acropetal and basipetal arrangement is that the older parts are at the bottom in the acropetal arrangement while the older parts are on the top in the basipetal arrangement.
Type of Inflorescence
Also, the acropetal arrangement is a modified form of the racemose inflorescence, while the basipetal arrangement is a modified form of the cymose inflorescence. Hence, this is also a difference between acropetal and basipetal arrangement.
Type of Growth of the Inflorescence
Moreover, the growth of the inflorescence is indeterminate in the acropetal arrangement, while the growth of the inflorescence is determinate in the basipetal arrangement.
The Growth of the Peduncle
The growth of the peduncle is indefinite in the acropetal arrangement while the growth of the peduncle is definite in the basipetal arrangement.
Branching of the Peduncle
Additionally, the growth of the peduncle is monopodial in the acropetal arrangement while the growth of the peduncle is either sympodial or multipodial in the basipetal arrangement.
The terminus of the Peduncle
Furthermore, the terminus of the peduncle does not develop a floret in the acropetal arrangement, while the terminus of the peduncle develops a floret in the basipetal arrangement.
First Floret
Besides, the first floret occurs in the base of the peduncle in the acropetal arrangement, while the first floret occurs at the top of the peduncle in the basipetal arrangement.
Formation of Florets
Importantly, the formation of florets is indeterminate in the acropetal arrangement, while the formation of florets is determinate in the basipetal arrangement.
Arrangement of Florets
One other difference between acropetal and basipetal arrangement is that the arrangement of florets is centripetal in the acropetal arrangement, while the arrangement of florets is centrifugal in the basipetal arrangement.
Opening of Florets
Florets open at short intervals in the acropetal arrangement, while florets open at long intervals in the basipetal arrangement.
Grouping of Florets
The grouping of flowers is less common in the acropetal arrangement, while the grouping of flowers is more common in the basipetal arrangement.
Formation of Fruits
Also, the fruits form at the base in the acropetal arrangement, while fruits form at the top in the acropetal arrangement.
Protection of Fruits
The newly forming florets do not protect fruits in the acropetal arrangement, while the newly-forming florets protect the fruits in the basipetal arrangement.
Conclusion
Acropetal Arrangement is the development of florets from the base towards the apex of the peduncle. Therefore, old florets occur at the base of the peduncle while the buds occur at the apex. Also, the first floret of the acropetal arrangement opens at the base, and the fruits first form at the base. On the other hand, in the basipetal arrangement, the florets develop from the apex towards the base of the peduncle. So, the old florets always occur at the top while the buds occur towards the base. Additionally, the first floret opens at the terminus of the peduncle in the basipetal arrangement as well as the first-forming fruits. Hence, the main difference between acropetal and basipetal is the direction of development of florets on the peduncle in each inflorescence.
References:
1. Manisha, M. “Types of Inflorescence: 5 Types (With Diagram) | Plants.” Biology Discussion, 12 Dec. 2016, Available Here.
Image Courtesy:
1. “Desmodium heterocarpon at Kadavoor” By © 2010 Jee & Rani Nature Photography (CC BY-SA 4.0) via Commons Wikimedia
2. “Fiore di geranio” (CC BY-SA 3.0) via Commons Wikimedia
Leave a Reply