Investigating plant hormones (PAG) - Maize seeds? Alternatives?

Discussion in 'Supporting Biology' started by Jimbob1988, Feb 27, 2020.

  1. Morning all,

    Have a request for PAG 11.4 (OCR) which looks into the influence of auxin, gibberellin etc on seed and seedling growth.

    The document recommends maize seeds, but could one use sweetcorn instead (bought from a garden center)? Alternatively, would the seeds of popcorn that haven't been popped be suffice?

    Many thanks :)
  2. same thing maize is sweet corn
  3. I always use radish for this. Tried the maize but it never grew even when I got a fresh batch. Radishes grow well and quite quickly.
  4. Popcorn seeds could be dead - Edexcel use cress or mustard seeds
    Jimbob1988 likes this.
  5. Same family but different :)

    Just asking as the former is harder to acquire than the latter.
  6. What I thought also :)
  7. I'll try radishes :)
  8. Not for growing seedlings! Effectively exactly the same as the maize is harvested late to get seeds hard on the cob, sweet corn IS the same thing but harvested with seeds soft on the cob. They may be different varieties but they are the same species and both work equally well for this experiment which is what the question was about.
  9. @Jimbob1988 - Just had a thought though - I'm not aware of the OCR experiment but if they are required to mess about with shoot tips (cut off, place on agar cubes, re-position etc) then they will need a big shoot so Maize is great as the shoot can be up to 2 mm diameter and without interfering leaves for quite a while. If you use radish, mustard or cress then they will find it very difficult to do any manipulation of the shoot because of the size and the quick appearance of leaves.
    maize - clear large tip to work with
    Mustard - no tip to work with
  10. Thanks for this :)

    I will use sweetcorn as it seems to be easier to get a hold of.

    Many thanks :)
  11. FYI
    In places outside North America, Australia, and New Zealand, corn often refers to maize in culinary contexts. The narrower meaning is usually indicated by some additional word, as in sweet corn, sweetcorn, corn on the cob, baby corn, the puffed confection known as popcorn and the breakfast cereal known as corn flakes.
    They are all zea (maize)
  12. What would the agar cubes be used for in this experiment (can't find nothing on youtube)?

    Could it be to contain different concentrations of the plant hormones so students can place the seedlings within?

    Many thanks :)
  13. Many thanks :)

    I grow popcorn, sweetcorn and maize down my allotment :)

    Seems one needs to go to more specialist online supplies for the former and latter. This reminds me to buy my seeds in for the year! :)
  14. I always use wheat - mainly because I found a large tub of it in the back of a tray. Seems to work for these purposes - in that the students can use it to set up their experiments. As for results, it depends how closely you look and your interpretation of the seedlings, to see if the various variables have made a difference. I think its one where the students get as many marks for designing the experiment and saying what might have gone wrong rather than needing to get textbook results.
    Jimbob1988 likes this.
  15. Perfect :)

    Does anyone know how long the plant hormone solutions will keep once made?

    Many thanks :)
  16. I went off piste and ended up putting the auxin and giberellic acid into vaseline so the kids can just apply it with a cocktail stick. The vaseline mixes have been in the back of my fridge for years and get an annual outing. As I said, no idea if it actually has any effect, but its a good discussion point for the kids and shows they overcame the problem of how to apply GA or auxin onto the shoots.
  17. As I said, I don't know the OCR experiement so I was just suggesting the experiments the maize can be used for - I remember if you cut the shoot off and place it on an agar cube then the auxin diffuses from the tip into the agar, you then can throw the tip away and place the cube 'off centre' on a fresh decapitated tip and it will bend according to where the agar is placed.
  18. We use wheat. Varying results. Doing this next week & week after. Do you use starch agar/ Nutrient agar with starch?
    Teachers here always want agar on plates rather than cubes.
  19. It would depend which experiment you are doing. The experiment being discussed here, you would just use plain technical agar cubes.

    There is another separate experiment which uses technical agar with starch plates, half of which have been dosed with giberellic acid, on which you place germinating wheat seeds to show what effect GA has on the production of amylase in the germinating seeds.
  20. Yes ours is the latter. I make the starch agar. Last year teacher wanted Nutrient/starch agar. Only using the technical this year.
    Snailo likes this.