The proteid substance of the mass of the grain, of the globoid, and of the crystalloid, reacts differently with different reagents and dyes.
The ground substance and the crystalloids are soluble in dilute alkali, while the globoids are insoluble in dilute alkali.
The ground substance and crystalloids are soluble in sodium phosphate, while the globoids are insoluble in sodium phosphate.
Calcium oxalate is insoluble in alkali and acetic acid, but it dissolves in hydrochloric acid.
PLATE 77a
Aleurone Grains
1. Curcas (Jatropha curcas, L.).
2. Sunflower seed (Helianthus annuus, L.).
3. Flaxseed (Linum usitatissimum, L.).
4. Bitter almond (Prunus amygdalus, amara, D.C.).
5. Croton-oil seed (Croton tiglium, L.).
6. Sesame seed (Sesamum indicum, L.).
7 and 8. Castor-oil seed (Ricinus communis, L.).
CRYSTALS
Calcium oxalate crystals form one of the most important inorganic cell contents found in plants, because of the permanency of the crystals, and because the forms common to a given species are invariable. By means of calcium oxalate crystals it is possible to distinguish between different species. In butternut root bark, for instance, only rosette crystals are found, while in black walnut root bark—a common substitute for butternut bark—both prisms and rosettes occur. This is only one of the many examples which could be cited.
These crystals, for purposes of study, will be grouped into four principal classes, depending upon form and not upon crystal system. These classes are micro-crystals, raphides, rosettes, and solitary crystals.