M.SC. BOTANY SEM - IV MGSU, BIKANER

Self Incompatibility ( स्वअनिषेच्यता ):- ·      जब एक पुष्प के परागकण उसी पुष्प या उसी पौधे के अन्य पुष्प को निषेचित करने में असमर्थ होते हैं तथा अन्य पौधे के पुष्प को निषेचित करने में समर्थ होते हैं तो इसे स्वअनिषेच्यता कहते हैं। लगभग 3000 से भी अधिक पौधों में यह पायी जाती है। ( When pollens of a flower are unable to fertilize the same flower or other flower of the same plant and are able to fertilize the flower of the other plant, it is called self-incompatibility. It is found in more than 3000 plants. ) ·      जब एक अनिषेच्य परागकण वर्तिकाग्र को परागित करता है तो यह निम्न 4 अवस्थाओं में से किसी एक पर वृद्धि को रोक लेता है जिससे स्व निषेचन असफल हो जाता है:- ( When an incompatible pollen pollinates the stigma, it stops growth at any one of the following 4 stages, causing failure of self-fertilization:- ) i.  वर्तिकाग्र पर परागकण अंकुरित नहीं होता है। ( Pollen does not germinate on stigma. )    ii.   वर्तिकाग्र पर परागकण अंकुरित होता है परन्तु परागनाल वर्तिकाग्र को भेद नहीं पाती है। (

Pollen Pistil Interaction:- > Pollination→Pollen adhesion→ Pollen hydration→ Pollen germination→ Pollen tube entry into stigma→ Pollen tube growth to the style→ Pollen tube entry into the ovule and embryo sac → Double fertilization.  > All the events leading from pollination to release of gametes in the embryo sac form a part of pollen pistil interaction is called Programic phase. Structure of Pistil:-  The female reproductive organ of the flower is called Gynoecium and the individual member is called pistil.Pistil is divisible into lower bulbous portion- Ovary, the long filamentous structure -style and the upper part of the style called stigma. All the three part of the pistil enjoy a wide degree of diversity as far as taxonomic point of view.But whatever may be the diversity, it is adapted to receive the pollen, aid its germination and subsequently entry of the pollen tube into the ovary, ovule and finally into the embryo sac for fertilization.The ultimate aim to acomplish the

Types of ovule:-  On the basis of the position of the micropyle with respect to the funiculus, mature ovule can be classified into six main types. These are: 1. Orthotropous ovule:- Orthotropous ovule is also known as atropous. It is upright. In this type the micropyle, chalaza and the funiculus lie in one straight line as in Polygonaceae and Piperaceae. 2. Anatropous ovule:- In this type, the funiculus is long; the body of the ovule becomes completely inverted so that micropyle comes to lie close to the base of the funiculus. This happens due to unilateral growth of the ovule. The nucellus remains straight so micropyle and chalaza lie in one line and funiculus lie parallel to it. It is the most common type of ovule inAngiosperms. 3. Campylotropous ovule:- In campylotropous ovules body of the ovule is not completely inverted, the curvature is less than that in anatropous ovules. The micropyle and chalaza do not lie in the straight line and the funiculus lies at right angle to the ch