Plant Tissues

Flashcards about plant tissues based on lecture notes.

Audi

Undifferentiated tissues = meristems. Groups of cells similar in origin, structure, and function.

Veidotājaudi jeb meristēmas

Tissues whose cells divide and differentiate, forming all plant tissues. Provides growth in length and thickness.

Meristēmas īpašības

Intensive division and differentiation into other tissues.

Veidotājaudu atrašanās vietas augos

Shoot (apical) meristems, root (apical) meristems, lateral meristems (cambium) provide growth in thickness. Buds and root tips provide growth in length.

Sānu meristēma - kambijs

Cambium provides stem growth in thickness. Found in some ferns, gymnosperms, and dicots.

Kambija šūnas

Divides in both directions – forming wood inwards and phloem outwards. Seasonal activity in temperate climate trees – forms annual rings.

Segaudu funkcijas

Protects plants from adverse environmental conditions, provides and regulates transpiration, and ensures gas exchange.

Segaudu veidi

Epidermis (leaves, fruits, flowers, annual stems, roots) and bark (periderm; multigenerational stems, roots).

Sakņu epidermas šūnas

Epidermal cells in the root absorption zone form root hairs, increasing the absorption surface. Root epidermis is called rhizodermis.

Epiderma

Transparent cell layer. Guard cells in stomata have chloroplasts.

Atvārsnītes

Gas exchange and transpiration occur through stomata. Stomata consist of 2 guard cells with a stomatal pore and a respiratory chamber.

Atvārsnīšu kustības

Light (opens), water (closes when lacking), temperature.

Miza (kreve)

Most trees and shrubs retain periderm for part of their life, then replaced by bark. Bark consists of many dead periderm layers – corky tissue – suberin accumulates in cell walls.

Kolenhīma

Unevenly thickened cell walls, living cells, in leaf veins and annual plant parts.

Sklerenhīma

Evenly thickened cell walls, lignin accumulates in cell walls, dead cells, in stems and roots.

Mehāniskie audi (balstaudi)

Mechanical tissues (supporting tissues) - support function.

Sklerīdas (akmensšūnas)

Give local strength. Form fruit and seed coats.

Vadaudi

Vascular plants (ferns, seed plants). Functions: conduction and mechanical support.

Vadaudu veidi

Wood (xylem) and phloem.

Koksne (ksilēma)

Dead cells, tracheids, transport minerals and water from roots to leaves.

Lūksne (floēma)

Living cells, sieve tubes (no nucleus) and companion cells, transport organic substances and water from leaves to storage organs.

Pamataudi jeb parenhīma

Living cells with thin cell walls. Functions: photosynthesis, storage, fills space between other tissues.

Lapas pamataudi - mezofils

Leaf ground tissue - mesophyll, assimilatory tissue. Performs photosynthesis and storage of organic substances.

Pamataudi – uzkrāšanas funkcija

Organic substances accumulate in parenchyma of fruits, seeds, roots, shoots and root modifications. Cells contain starch grains.