Tag: phanerogams

Gymnosperms lack typical companion cells and instead possess albuminous cells (or transfer cells) associated with sieve cells. The metabolic activity and functional control of the sieve elements in gymnosperms are regulated by the nucleus of these albuminous cells.

A male cone contains microsporophylls where male gametophytes ( pollen ) are produced and are later carried by wind to female gametophytes. The megaspore mother cell in the female cone divides by meiosis to produce four haploid megaspores; one of the megaspores divides to form the female gametophyte. So the correct option is 'Male and female gametophytes are independent of the sporophyte'.

Gymnosperms are vascular seed plants that include trees, shrubs, and lianas, but they do not form true herbaceous plants in the botanical sense of true herbs. Thus, herbs are the correct answer as they lack the woody persistent stems typical of gymnosperms.

The Gymnosperms originated during the late paleozoic era but floursihed very well during mesozoic era. Hence, the mesozoic period is called as 'Age of Gymnosperms'.

Gymnosperms are naked seed plants. The ovules are freely exposed before and after fertilisation.

The derivation of the word "gymnosperm" means naked seeds and is from the Greek words 'gymno' meaning naked or bare and 'sperm' meaning seed. 

The order Gnetales is considered to have several features that resemble angiosperms, such as the presence of vessels in the xylem and the structure of their reproductive organs.

Angiosperms and Gymnosperms resemble each other in many characteristics on of which is the presence of ovule. The difference lies in the appearance of ovule, in Angiosperm the ovule is enclosed in ovary, whereas in Gymnosperms the ovule is naked. 

Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. Gymnosperms, like all vascular plants, have a sporophyte-dominant life cycle. The gametophyte is relatively short-lived. Two spore types, microspores and megaspores, are typically produced in pollen cones or ovulate cones, respectively. 

Zoodiogamy is a type of fertilization in plants, wherein the male gametes or antherozoids swim in a film of water to the female gametes present in the archegonium. This type of plant reproduction relates to evolution and  is found in lower gymnosperms besides algae, bryophytes and pteridophytes.