Developmental and reproductive strategies of two marine algae <i>Gracilaria</i> <i>corticata </i>(Gigartinales, Rhodophyta) and <i>Asparagopsis taxiformis</i> <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:HiddenHorzOCR;color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">(Bonnemaisoniales, Rh<span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">odophyta) from Port Okha (<span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:HiddenHorzOCR;color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">Gujarat), <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">west coast of India</span></span></span></span>

Abstract

The coastal ecosystem of Port Okha (Gujarat) has distinct supratidal, intertidal and subtidal zones which demand specific or particular developmental and/or reproductive adaptations of existing algae. <i>Gracilaria corticata </i>grows in

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">intertidal regions whereas <i>Asparagopsis taxiformis </i>occurs in subtidal regions. In <i>G</i>. <i>corticata </i>wavy outline, compact arrangement of cortex and medulla, wall ingrowths in the medullary cells at thallus-holdfast transition zone and sulphated polysaccharides in the intercellular mucilage provides strength and flexibility to the thallus and protect the seaweeds against physical damage and constant environmental stress conditions. In contrast, the rhizomatous region of <i>A</i>. <i>taxiformis </i>does not anatomically differ from the thallus and is not modified because the plant grows in the tidal fringe which is not subjected to strong wave action. The well developed rhizomatous region helps the plants in propagation. <i>Gracilaria corticata </i>is a dioecious plant with three distinct season specific ph ases of diplobiontic life-cycle. However, <i>A. taxiformis </i>completes its life-cycle in two phases i.e. gametophyte and <span style="font-size: 14.0pt;line-height:115%;font-family:" times="" new="" roman";mso-fareast-font-family:="" hiddenhorzocr;color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;="" mso-bidi-language:hi"="" lang="EN-IN">carposporophyte. <span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">The carposporophyte phase of two red algae is concerned with amplification of the diploid stage, because fertilization chances are meagre due to non-motile sperms. The carpospores are gorged with floridean starch grains, fibrous vesicles and chloroplasts.</span></span></span>