Botany and Plant Science

Secondary phloem is formed by vascular cambium during secondary growth in vascular plant. Generally, it remains functional for one year but in some plants more than one year, e.g. Tilia and Salix.

The correct matching is: Hydrathodes - (3) leaf tips responsible for guttation; Collenchyma - (2) mechanical tissue with living cells and pectin-rich walls; Periblem - (4) meristem for cortex development (periblem is the ground meristem); Tyloses - (1) balloon-like xylem parenchyma protrusions into tracheary elements.

Haustorial roots, also known as sucking roots, found in parasitic plants like cuscuta, are the adventitious roots which enter the most host plant developing contact with xylem and phloem, and suck food and water from them.

A. Meristem               iii. Actively dividing cells B. Parenchyma         i. Photosynthesis, storage C. Collenchyma        ii. Mechanical support D. Sclerenchyma      v. Sclereids E. Epidermal tissue  iv. Stomata

This is the correct option. Growth of pollen towards the ovule - Chemotropism Winding of tendrills towards the support - Positive thigmotropism This is a wrong option as 'b' is correctly matched.  Bending of roots towards water - Positive hydrotropism Winding of tendrills towards the support - Positive thigmotropism

Tropism means movement in response to stimuli. Plants show movement in response to stimuli.  Chemotropism is the movement of plants in response to chemicals. It can be away or towards chemicals, e.g. growth of pollen tubes towards ovules in response to some chemical substances that are secreted by ovules to attract pollen tubes.

It is happening during stage 3 of endospore formation. In second stage an inward folding of the cell membrane to enclose part of the DNA occurs and produces the forespore septum which is followed by the next stage in which the membrane continues to grow and engulfs the immature spore in a second membrane.

Grafting and budding are methods of asexual plant propagation that join plant parts, so they will grow as one plant. These techniques are used to propagate cultivars that will not root well as cuttings or whose own root systems are inadequate. One or more new cultivars can be added to existing fruit and nut trees by grafting or budding.  The portion of the cultivar that is to be propagated is called the scion. It consists of a piece of shoot with dormant buds that will produce the stem and branches. The rootstock, or stock, provides the new plant’s root system and sometimes the lower part of the stem. The cambium is a layer of cells located between the wood and bark of a stem from which new bark and wood cells originate.

To avoid self pollination, maturation of stamens and pistils occurs at different times, which is called dichogamy.

It is a complex fertilisation mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte with two male gametes (sperms).

After fertilisation, diploid secondary nucleus becomes triploid. Initially it is diploid, but it fuses with one of the male gametes which is haploid; so finally after fusion, it becomes triploid i.e. 3n. Hence, it is the correct answer.

In a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous mother cells.

Pollen grains are the haploid structures which represent male or micro gametophytes.

It is formed by an enlarged, fleshy, hollow receptacle with multiple ovaries on the inside surface. In essence, it is really a fleshy stem with a number of flowers, so it is considered both a multiple and accessory fruit. It develops from hypanthodium inflorescence.

Microsporogenesis comprises the events which lead to the formation of the haploid unicellular microspores. It occurs in anther.