Noun:

மாவித்தி,

megaspores தமிழ் அர்த்தத்தின் உதாரணம்:

பூக்கும் தாவரங்களில், இரண்டாவது உயிரணு ஒன்று, மாவித்திக்குழியத்தில் இருக்கும் வேறொரு கருவுடன் இணைந்து பல்மடிய நிலையிலுள்ள வித்தகவிழையத்தை உருவாக்கும்.

சூலானது உட்புறமாக மாவித்திக் குழியம் (megasporocyte) என்னும் பகுதியையும், அதனைச் சூழ்ந்திருக்கும் மூலவுருப்பையகம் (nucellus) என்னும் பகுதியையும், வெளிப்புறமாக ஒரு உறை போன்று பாதுகாப்பிற்காக அமைந்த சூலுறை (integument) என்ற பகுதியையும் கொண்ட ஒரு அமைப்பாகும்.

பின்னர் சூலின் உட்புறமாக இருக்கும் மாவித்திக் குழிய உயிரணுவில் ஏற்படும் ஒடுக்கற்பிரிவு எனப்படும் கலப்பிரிவு செயல்முறை மூலம், ஒருமடிய மாவித்தி (Megaspores) எனப்படும் சூல்முட்டை உயிரணுக்களை உருவாக்கும்.

மாவித்திர, பிலியந்தலை இல் வசிக்கும் இவர் பௌத்த மதத்தைச் சேர்ந்தவர்,.

megaspores's Usage Examples:

The fructification consists of long, lax spikes, with whorled sporophylls; indications of megaspores have been detected in the sporangia.

The spores of this genus are curiously winged, and intermediate in size between the microspores and megaspores of Lepidostrobus; the question of homospory or heterospory is not yet decided.

Some Calamites were heterosporous, sporangia with microspores and megaspores being found in the same cone.

In the megasporangium, on the other hand, the four megaspores, which arise from a single mother-cell, are nourished at the expense of the other sporogenous cells and of the tapetum.

These latter bear spores of two kinds, microspores and megaspores, in separate sporangia.

These, as in Gymnosperms, are of two kinds, microspores or pollen-grains, borne in the stamens (or microsporophylls) and megaspores, in which the egg-cell is developed, contained in the ovule, which is borne enclosed in the carpel (or megasporophyll).

It has been shown by Lawson that in Sequoia sempervirens (Annals of Botany, 1904) and by other workers in the genera that several megaspores may attain a fairly large size in one prothallus.

It has recently been stated, however, that the supposed Algae are in reality the megaspores of Vascular Cryptogams.

The megaspores, of which there are many in the megasporangium, have a diameter about three times that of the microspores.

In Selaginellites Suissei there was a definite strobilus bearing both microand megasporangia; in each of the latter from 16 to 24 megaspores were contained; in Selaginellites primaevus, however, the number of megaspores was only 4, and the resemblance to a recent Selaginella was thus complete.

and contain either an im The upper sporangia contain numermense number of minute ous microspores; in each of the lower spores or a very small number sporangia four megaspores are shown.

The microspores are united by means of hardened protoplasm into one or more masses, while the solitary megaspores have a more or less complicated episporium.