Xerophyte

Schizochromism

The yellow or red appearance of some plants is more precisely caused by another aberration called "schizochromism". Here, though, the specific green pigment (chlorophyll) is missing

Description

Obregonia denegriiSN|2100]]SN|2100]] f. surata (schizochromic form), only deviate from the standard species for the stem which is uniformly yellow due to the absence (or very reduced production) of chlorophyll pigments. This form with yellow stems is very attractive and highly prized. This schizochromic form is always seen grafted on stronger columnar species, and cannot can be grown on its own roots. The typical Obregonia denegriiSN|2100]]SN|2100]] (commonly known as the "artichoke cactus") is among the most famous of all cacti for is unique shaped stem. It grows almost always as a solitary plant levelled with the ground, with the sunk and woolly apex. It is considered an intermediate form between Ariocarpus and Lophophora.Variegation, albinism schizochromism.

Variegated Form

A variegated plant has sectors, patches or stripes with two or more different colours, even distinct shades of green. Plants with variegated stems or leaves are often attractive and highly prized. In most species the stems or leaves are normally green, and variegated epidermis is an uncommon mutation, termed a chimera. A chimeral variegation is due to losing the ability to produce chlorophyll in some of the plant’s tissue, so that this tissue is no longer green. Tissues lacking chlorophyll are usually white or pale yellow coloured (due to carotenoid pigments) or red (due to betalain or anthocyanin pigments) contrasting with the normal green tissue. There are several forms of variegation, depending on the tissues that have been affected. The variegation in some forms is unstable. The extent and nature of the variegation can vary, and sometimes the plant will return to the green form. In others it is stable and does not change under normal conditions. Because the variegation is due to the presence of two kinds of plant tissue, propagating the plant must be by a vegetative method of propagation that preserves both types of tissue in relation to each other.