Lecture 12: Vascular Plants and VAscular Tissue

What are the four major innovations in the evolution of plants?

1. Embryophyte, 2) Vascular tissue, 3) Seed evolution, 4) Flower evolution.

What is the primary function of vascular tissue in plants?

To transport water, nutrients, and organic compounds throughout the plant.

What is the role of xylem in vascular plants?

Xylem conducts water and minerals from the roots to the leaves and provides support.

What are the two types of xylem cells?

Tracheids and vessels.

How does transpiration-cohesion work in the movement of water in xylem?

Water evaporates from leaves, creating a negative pressure that pulls water up through cohesive water columns in the xylem.

What do phloem cells transport?

Phloem transports organic compounds like sugars, amino acids, and hormones from leaves to roots and other parts of the plant.

What are sieve elements in phloem?

Sieve elements are cells that conduct nutrients in phloem but lack nuclei and have porous end walls called sieve plates.

What is the energy requirement for loading compounds into phloem?

Loading compounds into phloem requires expenditure of energy.

What evolutionary trend is observed in the life cycle of seedless vascular plants?

The dominance of the sporophyte generation over the gametophyte.

What is a key requirement for the reproduction of seedless vascular plants?

Water is required for the sperm to swim for fertilization.

What is the function of phloem in vascular plants?

Phloem is responsible for transporting organic nutrients, primarily sugars, produced by photosynthesis throughout the plant.

How do xylem and phloem work together in vascular plants?

Xylem conducts water and minerals up from the roots, while phloem distributes the organic compounds produced in the leaves, allowing for efficient nutrient transport.

What is the significance of vascular tissue in plants?

Vascular tissue is crucial for the structural support and transport systems that enable plants to grow taller and thrive in various environments.

What are vascular plants?

Vascular plants are plants that have specialized tissues (xylem and phloem) for transporting water, nutrients, and food.

What adaptations allow vascular plants to live in diverse habitats?

The development of vascular tissue provides structural support and efficient transport, allowing vascular plants to adapt to various terrestrial environments.

What structures are involved in water absorption in vascular plants?

Roots are the primary structures involved in water absorption, which then travels through xylem to the rest of the plant.

What are the primary differences between xylem and phloem in terms of transport?

Xylem transports water and minerals upwards, while phloem transports organic compounds downwards and laterally.

What role do companion cells play in phloem?

Companion cells assist sieve elements in transport and loading of nutrients into the phloem.

What is the composition of xylem tissue?

Xylem is composed mainly of tracheids, vessel elements, and supporting fibers.

How do plants regulate water loss through xylem?

Plants regulate water loss through transpiration, controlled by the opening and closing of stomata.