High biological variability of plastids, photosynthetic pigments and pigment forms of leaf primordia in buds

Abstract

To study the formation of the photosynthetic apparatus in nature, the carotenoid and chlorophyllous pigment compositions of differently developed leaf primordia in closed and opening buds of common ash (Fraxinus excelsior L.) and horse chestnut (Aesculus hippocastanum L.) as well as in closed buds of tree of heaven (Ailanthus altissima P. Mill.) were analyzed with HPLC. The native organization of the chlorophyllous pigments was studied using 77 K fluorescence spectroscopy, and plastid ultrastructure was investigated with electron microscopy. Complete etiolation, i.e., accumulation of protochlorophyllide, and absence of chlorophylls occurred in the innermost leaf primordia of common ash buds. The other leaf primordia were partially etiolated in the buds and contained protochlorophyllide (0.5-1 μg g(-1) fresh mass), chlorophyllides (0.2-27 μg g(-1) fresh mass) and chlorophylls (0.9-643 μg g(-1) fresh mass). Etio-chloroplasts with prolamellar bodies and either regular or only low grana were found in leaves having high or low amounts of chlorophyll a and b, respectively. After bud break, etioplast-chloroplast conversion proceeded and the pigment contents increased in the leaves, similarly to the greening processes observed in illuminated etiolated seedlings under laboratory conditions. The pigment contents and the ratio of the different spectral forms had a high biological variability that could be attributed to (i) various light conditions due to light filtering in the buds resulting in differently etiolated leaf primordia, (ii) to differences in the light-exposed and inner regions of the same primordia in opening buds due to various leaf folding, and (iii) to tissue-specific slight variations of plastid ultrastructure.

Roles for Light, Energy, and Oxygen in the Fate of Quiescent Axillary Buds

“…Following dormancy, the bud resumes a quiescent but receptive state with a connected symplast. Studies of several woody species have shown that the internal tissues and leaf primordia of quiescent buds are largely etiolated and lack chlorophyll (Solymosi et al, 2012). The plastids in such buds, however, exist in different developmental stages that are partly related to the nature of the tissues in which they reside (Solymosi et al, 2012).…”

“…Studies of several woody species have shown that the internal tissues and leaf primordia of quiescent buds are largely etiolated and lack chlorophyll (Solymosi et al, 2012). The plastids in such buds, however, exist in different developmental stages that are partly related to the nature of the tissues in which they reside (Solymosi et al, 2012). For example, proplastid-like and etio-chloroplasts, respectively, were identified in the inner and outer leaf primordia of compactly closed common ash (Fraxinus excelsior) buds (Solymosi et al, 2012).…”

“…The plastids in such buds, however, exist in different developmental stages that are partly related to the nature of the tissues in which they reside (Solymosi et al, 2012). For example, proplastid-like and etio-chloroplasts, respectively, were identified in the inner and outer leaf primordia of compactly closed common ash (Fraxinus excelsior) buds (Solymosi et al, 2012). After bud burst, the emerging leaves contain regular chloroplasts, although they are not fully developed (Solymosi et al, 2012).…”

“…For example, proplastid-like and etio-chloroplasts, respectively, were identified in the inner and outer leaf primordia of compactly closed common ash (Fraxinus excelsior) buds (Solymosi et al, 2012). After bud burst, the emerging leaves contain regular chloroplasts, although they are not fully developed (Solymosi et al, 2012). However, in horse chestnut (Aesculus hippocastanum), closed buds contain proplastids, and the leaf primordia of the opening buds contain etioplasts or etio-chloroplasts, but not chloroplasts (Solymosi et al, 2006).…”

“…However, in horse chestnut (Aesculus hippocastanum), closed buds contain proplastids, and the leaf primordia of the opening buds contain etioplasts or etio-chloroplasts, but not chloroplasts (Solymosi et al, 2006). In tree-of-heaven (Ailanthus altissima) buds, both inner and outer leaf primordia contain chloroplasts and etio-chloroplasts (Solymosi et al, 2012). Hence, outer leaf primordia do not always contain more developed plastids than the inner leaf primordia.…”