Leaf Color Variation Research Articles

Precision phenotyping of imidazolinone-induced chlorosis in sunflower.

Chlorosis level is a useful parameter to assess imidazolinone resistance in sunflower (Helianthus annuus L.). The aim of this study was to quantify chlorosis through two different methods in sunflower plantlets treated with imazapyr. The genotypes used in this study were two inbred lines reported to be different in their resistance to imidazolinones. Chlorosis was evaluated by spectrophotometrical quantification of photosynthetic leaf pigments and by a bioinformatics-based color analysis. A protocol for pigment extraction was presented which improved pigment stability. Chlorophyll amount decreased significantly when both genotypes were treated with 10 μM of imazapyr. Leaf color was characterized using Tomato Analyzer® color test software. A significant positive correlation between color reduction and chlorophyll concentration was found. It suggests that leaf color measurement could be an accurate method to estimate chlorosis and infer chlorophyll levels in sunflower plants. These results highlight a strong relationship between imidazolinone-induced chlorosis and variations in leaf color and in chlorophyll concentration. Both methods are quantitative, rapid, simple, and reproducible. Thus, they could be useful tools for phenotyping and screening large number of plants when breeding for imidazolinone resistance in this species.

Prerequisites for evolution: variation and selection in yellow autumn birch leaves

Prerequisites for evolution: variation and selection in yellow autumn birch leaves

Isolation and expression of McF3H gene in the leaves of crabapple

The molecular mechanisms involved in leaf color variation were investigated in crabapple. Using the total RNA from the leaves of crabapple ‘Royalty’ as the template, the full cDNA of F3H (Flavanone-3-hydroxylase) gene (1,370 bp) was cloned by reverse transcription polymerase chain reaction and rapid-amplification of cDNA ends. The gene was named as McF3H, containing a 1,092-bp open reading frame encoding a protein of 364 amino acids. Corresponding genomic DNA sequence was 1,983 bp, containing two introns, and all the cleave sites obeyed the GT–AG rule. The expression of McF3H gene following leaf development was determined by real-time quantitative PCR in the leaves of three crabapple varieties, ‘Flame’ (both young and mature leaves are green), ‘Radiant’ (young leaves are orange to red and mature leaves are green) and ‘Royalty’ (both young and mature leaves are red to purple). The results showed that McF3H gene was expressed in both red and green leaves. But the expression levels of McF3H gene in ever-red-leafed ‘Royalty’ were significantly higher than in evergreen-leafed ‘Flame’ at all stages of leaf development. The transcript level in ‘Radiant’ showed the similar temporal pattern to the variation of leaf color following its leaf development. Also, the anthocyanin accumulation levels in crabapple leaves were consistent with the color variation of leaves. These results suggest that McF3H gene is one of the important structure genes related to anthocyanin accumulation in crabapple leaves and the red coloration of crabapple leaf is associated with high expression level of this gene.

Micropropagation of iridaceae—a review

The Iridaceae contains many hundreds of attractive species that have been overlooked for horticultural development. The incredible variation in flower and leaf shape, size and colour suggest this little-tapped resource could offer great opportunities for developing new commercial ornamental products. Micropropagation has increasingly become a valuable tool assisting breeders to release new species and cultivars into the market more rapidly. Here we review the progress made in Iridaceae micropropagation genus by genus, and highlight the potential for future expansion in this field.

Red Reveals Branch Die-back in Norway Maple Acer platanoides

Physiological data suggest that autumn leaf colours of deciduous trees are adaptations to environmental stress. Recently, the evolution of autumn colouration has been linked to tree condition and defence. Most current hypotheses presume that autumn colours vary between tree individuals. This study was designed to test if within-tree variation should be taken into account in experimental and theoretical research on autumn colouration. Distribution of red autumn leaf colours was compared between partially dead and vigorous specimens of Norway maple (Acer platanoides) in a 3-year study. In August, the amount of reddish foliage was estimated in pairs of partially dead and control trees. Within-tree variation in the distribution of reddish leaves was evaluated. Leaf nitrogen and carbon concentrations were analysed. Reddish leaf colours were more frequent in partially dead trees than in control trees. Reddish leaves were evenly distributed in control trees, while patchiness of red leaf pigments was pronounced in partially dead trees. Large patches of red leaves were found beneath or next to dead tree parts. These patches reoccurred every year. Leaf nitrogen concentration was lower in reddish than in green leaves but the phenomenon seemed similar in both partially dead and control trees. The results suggest that red leaf colouration and branch condition are interrelated in Norway maple. Early reddish colours may be used as an indication of leaf nitrogen and carbon levels but not as an indication of tree condition. Studies that concentrate on entire trees may not operate at an optimal level to detect the evolutionary mechanisms behind autumnal leaf colour variation.

Indirect shoot organogenesis from leaves of Dieffenbachia cv. Camouflage

A novel protocol for indirect shoot organogenesis of Dieffenbachia cv. Camouflage was established using leaf explants excised from in vitro shoot cultures. The frequency of callus formation reached 96% for explants cultured on Murashige and Skoog (1962) basal medium supplemented with 5 μM thidiazuron and 1 μM 2,4-dichlorophenozyacetic acid. The number of shoots regenerated was high, with up to 7.9 shoots produced per callus cultured on basal medium supplemented with 40 μM N6-(Δ2-isopentenyl)adenine and 2 μM indole-3-acetic acid. Regenerated shoots rooted well in a soilless substrate, acclimatized ex vitro at 100%, and grew vigorously under shaded greenhouse conditions. Somaclonal variations in leaf variegation, color, and morphology have been observed in regenerated plants.

Leaf Color Stability during Plant Development as an Index of Leaf Color Variation among Micropropagated Caladium

The developmental pattern of leaf color distribution during plant development in 10 cultivars of Caladium ×hortulanum Birdsey was investigated. We used the color occupying the largest area in the terminal leaf as the dominant color, and expressed the leaf color stability during plant development by the ratio of the percentage of the dominant color area in the terminal leaf to that of the dominant color area in the initial leaf (leaf color stability index). In some cultivars, leaf color stability index was clearly greater than 1 (leaf-color-unstable cultivar), but in some cultivars it was close to 1 (leaf-color-stable cultivar). In plants regenerated from leaf explants of leaf-color-unstable cultivars, many (21% to 43%) color variants were observed but only a few (0% to 6%) occurred from leaf explants of leaf-color-stable cultivars. Tissue culture appears to be a useful technique for rapid propagation based on leaf color stability in leaf-color-stable and leaf-color-unstable cultivars.

Auxins increase the occurrence of leaf-colour variants in Caladium regenerated from leaf explants

Leaf explants of Caladium ‘Pink Cloud’ were cultured in vitro on MS medium containing various auxins (NAA, IBA, IAA, 2,4,5-T and 2,4-D) in combination with cytokinin (BA). NAA gave the most vigorous in vitro propagation of this plant, and only 15% of the plants were leaf-colour variants on the medium containing 0.5 μmol NAA. Leaf colour variation was observed in all plants regenerated on the medium containing 2,4-D at 0.5–4.5 μmol. In hormone-free medium, only a few leaf-colour variants (6%) occurred, but the rate of plant regeneration was very low. Application of 0.5 μmol NAA together with 4.5 μmol BA seemed to be the most appropriate for in vitro propagation of Caladium ‘Pink Cloud’ with only a few leaf-colour variants.

Variations in African Violet `Crimson Frost' Micropropagated by Homogenized Leaf Tissue Culture

Adventitious buds regenerated from homogenized leaf tissue of Saintpaulia ionantha Wendl. `Crimson Frost' were micropropagated to determine types and frequencies of the variants obtained. Plants grown for one year in a greenhouse showed 67% variation and 33% normality. A higher rate of variation was observed in leaf color rather than in leaf shape. The variations in leaf color and leaf shape were 67% and 19%, respectively. In regard to flower type, greater numbers of semidouble and double types were obtained as compared to single types. Both flower types showed a much higher rate of normal (mixed) color (81%) as compared to pink, red or white (19%). An sodium dodecylsulfate polyacrylamide gel electrophoresis profile of protein extracted from leaves of the stock plants and the variants indicated no difference between them and did not reflect the variation in phenotype.

Effect of pruning on regrowth of cut foliage stems of seventeen Eucalyptus species

Summary. Seventeen species of Eucalyptus were subjected to trials investigating their suitability for floriculture and the effect of pruning on cut foliage production. There was variation in leaf colour within and between species, and in the time to phase change and flowering. There were significant differences at 16 months between species for tree height, trunk diameter and lignotuber diameter with E. globulus having the largest dimensions. Following pruning at 19 months, there was an initial significant interaction between species and pruning height in relation to tree height, height increment, and trunk and lignotuber diameter. After 1 year there were significant differences between species, in the length of stems, number of stems and total weight of stems, with E. globulus producing the highest number and weight of stems. There was a positive correlation of trunk diameter and lignotuber diameter at 3 and 6 months after pruning with the number of cut foliage stems produced at 12 months. For E. gunnii pruning to 1.0 m at 25 months produced the most stems at 6 months after pruning.

Genetic variation in height growth and leaf colour of Eucalyptus deglupta Blume at ages up to 16 months in Costa Rica

Results of three progeny tests of Eucalyptus deglupta in Costa Rica are described and discussed. High levels of additive genetic variation were found in height growth up to 16 months. Heritabilities were within the range typically found in forest trees. High levels of additive genetic variation and family heritabilities in leaf colour were also found. Purple leaves were associated with slow growth, and green leaves with fast growth. The best families showed a high degree of stability across the three sites. Predicted genetic gain from directed seed collections of the best mother-trees ranged from 12.4 to 15.8%.

Varietal Differences in Leaf Color Variation of Plants Regenerated from in vitro Culture of Leaf Blade in Caladium Cultivars

Expanding leaves of nine cultivars of caladium (Caladium Xhortulanum Birdsey) were cultured on modified MS medium supplemented with 1.0 mg•liter-1 BA and 1.0 mg•liter-1 NAA from which multiple shoot primordia were obtained. The multiple shoot primordia were in turn, cultured on modified MS medium without any growth regulators to regenerate plantlets.Leaf color variations in the plantlets regenerated from the multiple shoot primordia were very different among the nine cultivars. Leaf color variants were not observed in the plantlets regenerated from their multiple shoot primordia of 'Aaron', 'Frieda Hemple', 'John Peat', 'Candidum Junior', and 'C. R. 5', but they were observed with high frequency in those of 'Pink Cloud', 'White Wing', 'Rosary', and 'Ginger Land'.All leaf color variants in the regenerated plantlets changed from the white or red veins to the green. Variants regenerated from the multiple shoot primordia of 'Pink Cloud' and 'Ginger Land' had green veins and the laminas retained the color of the original parent plants. On the other hand, the variants regenerated from those of 'White Wing' and 'Ro•sa•ry' had both green laminas and veins.When the green vein variants of 'Pink Cloud', and green leaf ones of 'White Wing' and 'Rosary' were cultured, the regenerated plantlets appeared similar to the parental stock.

Leaf Color Variation in Soybean F2 Population Observed through Image Analyzer

Leaf Color Variation in Soybean F₂ Population Observed through Image Analyzer

Experimental studies on some observed variations in Luffa aegyptiaca

The causes of some observed variations in plant size and leaf morphology of populations of Luffa aegyptiaca were investigated experimentally. The effects of soil type, soil salinity, soil moisture content, and mineral nutrients on the germination and growth of this species were examined. The results indicate that variations in size and leaf morphology between the population groups earlier described probably were caused by variations in soil type and soil nutrients. Nitrate was responsible for variation in leaf colour, potassium for leaf invagination, and phosphorus and nitrate together for leaf texture. Nitrate also played a major role in the variation in leaf size while calcium played a subsidiary role. Within a single population, variations would possibly also be caused by differences in soil conditions, principally humus content, soil moisture content, and salinity. The wide adaptability exhibited by this species also helps to explain its distribution on a wide range of soils.