Lecture 4 DA Flashcards
Do gymnosperms require water for their sperm to reach the egg?
No.
Do gymosperms produce fruit? What are their seeds like?
They dont produce fruit, their seeds are naked.
What are fruit?
An ovary.
What surrounds the megasporangium of gymnosperms?
Integument.
Where does the megaspore of gymnosperm megasporangia develop?
In situ, within the seed.
Do the walls of gymnosperm megasporangia dihesce? What purpose does it serve?
It doesnt dihesce.
Is nutritive, nucellus.
What is the micropile? What develops here?
It is the recceptive tip of the megasporangia in gymnosperms.
When a pollen lands here on the integument, it develops into a pollen tube to the egg.
What do gymnosperms produce characteristically?
Cones.
What are strobili?
Reproductive organs on a cone.
Male - pollen, microsporangia
Female - ovule, megasporangia
Are microsporangia and megasporangia found on the same cone?
No, there are male and female cones.
Versus ferns, how do gymnosperms do reproductively, and why (6)?
Theyre more successful, but take a longer time. -They dont need water for sperm to reach the egg. -The seed can survive harsh conditions. -Has developed roots/leaves. Sunken stomata. -Has developed vasculature. -Uses resin to fight bacteria and fungi. -Has glaucous structures.
What are the three divisions of gymnosperms?
Coniferopsida - conifers
Cycadopsida - palm like trees
Gnetopsida - vessels and flowering like plants
What is used to classify gymnosperms into divisions?
Their reproductive organs generally decide which division.
What is the wood of coniferopsida like?
Has growth rings, and cambial layers, made of cambium to make wood.
What produces secondary xylem in coniferopsida, and in which region?
Cambial layer, in the meristematic region.
Are xylem found towards the centre or periphery?
Centre. Phloem are along the periphery.
What is true wood made of?
Secondary xylem.
What can be found in the outer periphery of coniferopsida aside from phloem? Can it be found in other gymnosperms?
Resin canals. Unique to coniferopsida.
Can gymnosperms produce fruit?
No, but they ca produce false fruits. True fruits are an outgrowth of the ovary wall, while gymnosperms produce fleshy cones.
What is special about ginkgoales?
TheMonotypic - one genus, one species.
Are cycadopsida true palms?
No, palms are angiosperms.
Are cycadopsida diecious?
Yes.
What are cycadales? What do they produce?
Order in cycadopsida. Produce toxic alkaloids.
What is special about the wood of gnetopsida?
Has vessels like angiosperms.
Are the leaves of gnetopsida veined?
No.
What are the genera of gnetopsida?
Ephedra
Gnetum
Welswitchia
What does the welswitchia resemble?
Fossils of plants from 200m years ago.
Is the sporophyte of gymnosperms dominant?
Yes.
What can be found in gymnosperm xylem?
Tracheids.
What are long and dwarf shoots, and which tree are they found in?
Found in pines.
Long shoots - unlimited growth.
Dwarf shoots - limited growth, few foilage, sclae-like leaves.
Are gymnoserms heterosporous?
Yes.
What is the sporophyte of gymnosperms like?
Large vascular plant, like a bush.
What is made within male and female cones?
Micro or megaspres respectively.
When a male cone is made, what does it replace?
A dwarf shoot.
What are the scales of male and female cones called?
Male - microsporophylls
Female - megasporophylls
What can be found on each microsporophyll of male cones?
Each has 2 pollen sacs, which are the microsporangia.
What do pollen sacs do (4)?
Undergo cellular differentiation to produce prothallial cells, 2 wings, 1 tube nucleus, and 2 sperm nuclei.
When a female cone is made, what does it replace?
A long shoot.
What can be found on each megasporophyll of female cones?
2 ovules.
Which species of conifers are used as farm shade in southeastern Australia?
fuck off
