Explants or regenerated shoots?

Hi Saba,

try some higher levels: for example 1, 1.25 and 1.5 mg/l. also you can try IAA.

What type of explants, what is the plant species and what is the purpose?

As I remember in plant biotechnology, we used something similar but in these concentrations:

(IBA) (1.0 mg/L)

Using bifactorial design of four concentrations for NAA and IBA (0.25, 0.50, 0.75 and 1.0 mg/L)

The basal medium with 0.5 to 0.75 mg/L of NAA were the best concentration for the rooting.

I hope it works for you!

Thank you all, the plant is crataegus . it is a shrub. The purpose is micropropagation and the shoot that didnt root, obtained from proliferation of axillary bud.

hi saba

Hawthorn have phenolic compound. Under cultivation gave better quickly! Because phenolic compounds affect the activity of auxin.

Boron also has an effect on in vitro rooting. And will affect auxin.

Reduce the duration of autoclaved medium. Enough about five minutes!

Also make sure that you use fresh material and original!

Did you provide darker environment.

In orchid, we apply activated charcoal aprroximately 0.05-0.1% in agar medium.

Nur, in case of MS will that be 1900 + 500 mg?

you could try activated charcoal for root initiation

I work with woody plants. You should increase the concentration of IBA or NAA if you add the auxins directely in to the medium. But i suggest a simple protocol we use in our lab: you have to excise uninodal explants with 1,5-2 cm long internode under the bud(s). Than, you dip their basal stem into 1-2 ml of a liquid inductive solution of water, IBA (5 mg/l) and sucrose (15 g/l), inside glass tubes. You put the cultures in the growth room at darkness condition for 3-5 days. At the end you can place the explants vertically in a lmedium withouth hormons (MS?). Good luck!

A further suggestion is to darken the basal part of rooting shoots. You could use activated charcoal (as reported by Shekhawat), or other soluble product (Brilliant black). A possibility is to spread a lot of small plastic black pearls upon the surface of the rooting medium.

It is possible that the light spectrum in the growing chamber may have an influence. When I worked with sugarbeet in vitro, I did not obtain any rooting while using cool white fluorescent tubes, but rooting was never more a problem after I substitute half of the cool white tubes with plant growing type tubes (such as Fluora or Gro-lux) which include the red part of the spectrum. The cycle was 16 h light/ 8 h dark.

Two types of plants exist: easy to root or hard to root. The first type gets a natural aptitude to develop adventitious roots: erbaceous plants or some woody plants are classified as easy to root. In opposite, hard to root plants need inductive treatments, which consist in high concentrations of auxins added to the medium or in pre-treatments consisting a dipping of the basal part of the explants by auxinic solutions (water, auxin and low concentration of sucrose - 10-15 g/l) for 3-6 days in darkness conditions before the emission of roots in agarised medium. The concentration and the type of auxins depend on the genotype characteristics. You could test the effect of different auxins (IBA, NAA, IAA) or 2,4 D. May be you haven't results because of the contemporary presence of auxins and cytokinins (wel known as antagonist growth regulators for rooting) added to the nutritive medium.

in which species and what is the type of explant you have used. Do you want direct rooting from explants?

Like to know what type of explant you are using. If it is difficult to root means you can try combination of NAA 1mg/l with IBA 5mg/l or can try NAA alone 22mg/l for two weeks and transfer to hormone free medium.

Hi

Try with half strength MS medium , Activated Charcoal can help too , different plant species or different varieties show different results when cultured in one a medium and some plants need longer time to root .

u can use combinations of hormones NAA, IAA, IBA with KN, BAP. half MS medium is another option. However, all depends on the plant u r working with. Sometimes even use of some antioxidants like ascorbic acid and other work.

What species are you working with ? Contact me on [email protected] or [email protected]

Hi,

what about your explants. are they still without roots?

May be a callus or necrotic tissue appeared on the base of shoots, that blocked transport of growth regulators?

Are you sure that concentration in your rooting medium is optimal for your plant? Supraoptimal concentration of auxins also could inhibit root induction. It may be genotype dependent.

And what about previous culture? I have had also a bad experience with rooting of shoots proliferated on BAP. In this case, try metatopoline as a good alternative.

Increase sugar and auxin concentration may also help rooting.

Please provide basic information before anyone can help.

1. What plant you are working with?

2. What growth regulators have you used?

3. What were the conditions of incubation?

Thanks

Several factors influence on root formation, such as genetics, developmental stage, hormones. Documented evidence declares that the low root formation ability (rooting-recalcitrant) of some plants are closely related to endogenous balance of phytohormones. Therefore, in rooting-recalcitrant plants high concentrations of auxin are required and the concentrations you used are much lower than usual.

Please try IAA as in some cases it works better (probably due to being naturally occurring auxin). Couple it with dark condition for a week. Another option can be using activated charcoal or PVP.

Good luck