The contents of photosynthetic pigments in the colored forms of cacti in comparison with other succulent plants
I.M. Skoulkin, Ph.D and E.P.Artemyeva

фото 1.

The purpose of the work is to check the following hypothesis: all the abnormal colored forms (ACF) of cacti are real chlorophyll-free mutants.

The tasks of the research are:
1. To determine the presence of photosynthetic pigments in ACF;
2. To compare the quantity of chlorophyll and carotinoids in ACF, stocks, succulents and common plants;
3. Evaluation of ration "chlorophylls to carotinoids" and "chlorophyll a to хлорофилл b" in ACF in comparison with 3 control groups.

фото 2.

Materials and methods. In summer 2000 we started the research of the contents of photosynthetic pigments - chlorophylls a and b and carotinoids in 9 different ACF of cacti including Eriocactus magnificus f. aurea, Chamaecereus silvestrii f. aurea, and 6 forms of Gymnocalycium mihanovichii var. friedrichii.

As there is no universal system of ACF names we used our own names based on the ACF's coloring at the moment of research:

• PURPLE - photo 1;
• RED - photo 2;
• PINK - sometimes is called "Pottii" (photo 3);
• ROSE - a pale form with rare dark spots (photo 4);
• MULTICOLOR - 3-colored yellow-red-green spotted form (most probably this is "Hibotan") (photo 5);
• BLACK - a dark brown form with pinkish fragments (most probably this is "Black Botan")(photo 6).

фото 3.

We also included growing on its own roots Gymnocalycium mihanovichii var. friedrichii s.str., a species that served as the base for most ACF Gymnocalyciums.

For comparison we took 7 species of cacti usually used as stocks (Hylocereus, Selenicereus and others), 18 species of succulents of Crassulaceae family and 3 species of non-succulent plants (lily-of-the-valley, oxalis, amaranth). All the plants except the 3rd group were kept for two month before the research in the greenhouse with the temperature about +30 °С in good natural lighting conditions.

фото 4.

We researched only the outer parts of the rind of the cacti together with epidermis 1.5 - 2 mm thick as the main part of the pigments is situated in this zone.

As for succulents, we took mainly the fragments of the middle part of the leaves.

The samples were fixed, then crumbled up to have the pigments extracted with 85% acetone. The concentration of the pigments was determined by spectrophotometer "Lomo" SF-46. The results were checked three times for all the species.

фото 5.

RESULTS AND DISCUSSION. Out of 4 groups of the studied plants the least quantity of chlorophylls was found in ACF cacti (table 1). Succulents of Crassulaceae family had a bit more. Stocks had about twice more green pigment. And deciduous plants, mainly heliophobe, had an order higher contents of chlorophylls which correspond to the known data.

We also included growing on its own roots Gymnocalycium mihanovichii var. friedrichii s.str., a species that served as the base for most ACF Gymnocalyciums.

фото 6.

For comparison we took 7 species of cacti usually used as stocks (Hylocereus, Selenicereus and others), 18 species of succulents of Crassulaceae family and 3 species of non-succulent plants (lily-of-the-valley, oxalis, amaranth). All the plants except the 3rd group were kept for two month before the research in the greenhouse with the temperature about +30 °С in good natural lighting conditions.

We researched only the outer parts of the rind of the cacti together with epidermis 1.5 - 2 mm thick as the main part of the pigments is situated in this zone.

As for succulents, we took mainly the fragments of the middle part of the leaves.

The samples were fixed, then crumbled up to have the pigments extracted with 85% acetone. The concentration of the pigments was determined by spectrophotometer "Lomo" SF-46. The results were checked three times for all the species.

Table 1