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प्रश्न
What do you infer from the term pycnoxylic?
उत्तर १
- Secondary growth is also traced in gymnosperms, E.g. Cycas and Pinus.
- The wood may be compact with narrow medullary ray this condition known as Pycnoxlic seen in Pinus.
- It is opposite to Manoxylic condition which is seen in Cycas.
उत्तर २
Pycnoxylic wood is compact with a narrow medullary rays. Example: Pinus
संबंधित प्रश्न
Write a note on the economic importance of gymnosperms.
Describe the important characteristics of gymnosperms.
Endosperm in gymnosperm is formed ______.
Mention two characters shared by gymnosperms and angiosperms.
Read the following five statements (i to v) and select the option with all correct statements:
- Mosses and lichens are the first organisms to colonise a bare rock.
- Selaginella is a homosporous pteridophyte.
- Coralloid roots in Cycas have V AM.
- Main plant body in bryophytes is gametophytic, whereas in pteridophytes it is sporophytic.
- In gymnosperms, male and female gametophytes are present within sporangia located on sporophyte.
In gymnosperms, megaspore mother cell divides meiotically to form four megaspores. Out of four megaspores, one develops into a multicellular structure termed as : ·
Gymnosperms are called naked seeded plants due to the absence of
Which of the following is not found in gymnosperms?
Plants of this group are diploid and well adapted to extreme conditions. They grow bearing sporophylls in compact structures called cones. The group in reference is ______.
The giant Redwood tree (Sequoia sempervirens) is a/an ______.
Each plant or group of plants has some phylogenetic significance in relation to evolution: Cycas, one of the few living members of gymnosperms is called as the ‘relic of past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?
In which plant will you look for mycorrhiza and corolloid roots? Also explain what these terms mean.
Lichen is usually cited as an example of ‘symbiosis’ in plants where an algal and a fungal species live together for their mutual benefit. Which of the following will happen if algal and fungal partners are separated from each other?
- Both will survive and grow normally and independent from each other.
- Both will die
- Algal component will survive while the fungal component will die.
- Fungal component will survive while algal partner will die.
Based on your answer how do you justify this association as symbiosis.
