4.2 Growth media: Synthetic or natural compounds? Blog entry week 08-11/2017

-Which are the main impediments for Bamboo multiplication?

Bamboos propagate naturally in two different ways: either through seeds as sexual reproduction or by culms or rhizome as vegetative propagation [1]. One of the main impediments for bamboo is that sexual reproduction through seeds is not fix and can take place every ten years or more, making it very seldom [2]. Moreover is the reproduction followed by death of the plant and seeds have a short viability, therefore leading to precarious spreading conditions [1]. Vegetative propagation through offset cuttings of rhizome or culms can be used but are not efficient enough for extensive multiplication. Given those characteristics, an in vitro multiplication of Bamboo for a large scale production makes sense and studies on this matter have been undertaken, for instance by Venkatachalam et al.

- Which measures can be taken to establish an efficient in vitro propagation system?

To establish an efficient in vitro propagation it is necessary to have a good starting material, for example a proven seed of the chosen specie. This material must be thoroughly disinfected to avoid any bacterial or fungal contamination prior to cultivate it on a chosen media. To chose this media, systematic experimentations are made with different concentrations of chemicals, hormones and plant growth regulators to find the best media corresponding to each stage of desired growth (i.e. shoot bud initiation, multiplication, regeneration, etc…). After germination, nodal explants are used for shoot bud initiation and then multiplied on chosen media. Once the multiplication is successfully done, a hardening and acclimatization are necessary before transferring the plants to the field.

- Cocos milk or similar natural compounds seem to be effective ingredients for in vitro cultures. Are there any disadvantages too?

Coconut water contains among other substances cytokinines, auxines, leucoanthocyanines and bioactive enzymes which have growth regulatory properties, making it a very useful compounds to promote cell division and rapid growth during shoot multiplication [1, 3]. However at higher concentration it can have an inhibitory effect and can cause vitrification of the roots [1]. Therefore concentrations have to be measured to know the concentration that will vary from one plant to another.

References:

[1] P. Venkatachalam, K. Kalaiarasi, S. Sreeramanan, Influence of plant growth regulators (PGRs) and various additives on in vitro plant propagation of Bambusa arundinacea (Retz.) Wild: A recalcitrant bamboo species. Journal of Genetic Engineering and Biotechnology (2015) 13, 193–200

[2] https://fr.wikipedia.org/wiki/Bambou

[3] https://fr.wikipedia.org/wiki/Eau_de_coco