MediumBiologyHigh School (11–12)Diversity of Living Organisms › Bryophytes and PteridophytesNumerical
A fern frond has 18 pinnae. Under each pinna there are 10 sori, and each sorus holds 25 sporangia…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A fern frond has pinnae. Under each pinna there are sori, and each sorus holds sporangia. Each sporangium releases spores. (a) How many sporangia are on the frond? (b) How many spores does it release?
Need a reminder? The key ideaShow
Pteridophytes are the first land plants with xylem and phloem. The main plant body is the diploid sporophyte, with true roots, stems and leaves. Sporangia on sporophylls make spores by meiosis (in many ferns, 16 spore mother cells give 64 spores in a sporangium); some form strobili. A spore grows into a free-living prothallus with antheridia and archegonia, and fertilisation needs water. Classes: Psilopsida, Lycopsida, Sphenopsida, Pteropsida.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Sporangia. sporangia.
Step 2. Spores. spores.
Answer: (a) sporangia; (b) spores.
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