scholarly journals How Much Pigment Should Flowers Have? Flowers With Moderate Pigmentation Have Highest Color Contrast

2021 ◽  
Vol 9 ◽  
Author(s):  
Casper J. van der Kooi

Floral pigments are a core component of flower colors, but how much pigment a flower should have to yield a strong visual signal to pollinators is unknown. Using an optical model and taking white, blue, yellow and red flowers as case studies, I investigate how the amount of pigment determines a flower’s color contrast. Modeled reflectance spectra are interpreted using established insect color vision models. Contrast as a function of the amount of pigment shows a pattern of diminishing return. Low pigment amounts yield pale colors, intermediate amounts yield high contrast, and extreme amounts of pigment do not further increase, and sometimes even decrease, a flower’s color contrast. An intermediate amount of floral pigment thus yields the highest visibility, a finding that is corroborated by previous behavioral experiments on bees. The implications for studies on plant-pollinator signaling, intraspecific flower color variation and the costs of flower color are discussed.

2013 ◽  
Vol 47 (5) ◽  
pp. 437-453
Author(s):  
Zhu Manlan ◽  
Wang Liangsheng ◽  
Zhang Huijin ◽  
Xu Yanjun ◽  
Zheng Xuchen ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yu Qiao ◽  
Qiming Cheng ◽  
Yutong Zhang ◽  
Wei Yan ◽  
Fengyan Yi ◽  
...  

Abstract Background Sainfoin (Onobrychis viciifolia Scop) is not only a high-quality legume forage, but also a nectar-producing plant. Therefore, the flower color of sainfoin is an important agronomic trait, but the factors affecting its flower phenotype are still unclear. To gain insights into the regulatory networks associated with metabolic pathways of coloration compounds (flavonoids or anthocyanins) and identify the key genes, we conducted a comprehensive analysis of the phenotype, metabolome and transcriptome of WF and AF of sainfoin. Results Delphinidin, petunidin and malvidin derivatives were the main anthocyanin compounds in the AF of sainfoin. These substances were not detected in the WF of sainfoin. The transcriptomes of WF and AF in sainfoin at the S1 and S3 stages were obtained using the Illumina HiSeq4000 platform. Overall, 10,166 (4273 upregulated and 5893 downregulated) and 15,334 (8174 upregulated and 7160 downregulated) DEGs were identified in flowers at S1 and S3 stages, respectively (WF-VS-AF). KEGG pathway annotations showed that 6396 unigenes were annotated to 120 pathways and contained 866 DEGs at S1 stages, and 6396 unigenes were annotated to 131 pathways and included 1546 DEGs at the S3 stage. Nine DEGs belonging to the “flavonoid biosynthesis”and “phenylpropanoid biosynthesis” pathways involved in flower color formation were identified and verified by RT-qPCR analyses. Among these DEGs, 4CL3, FLS, ANS, CHS, DFR and CHI2 exhibited downregulated expression, and F3H exhibited upregulated expression in the WF compared to the AF, resulting in a decrease in anthocyanin synthesis and the formation of WF in sainfoin. Conclusions This study is the first to use transcriptome technology to study the mechanism of white flower formation in sainfoin. Our transcriptome data will be a great enrichment of the genetic information for sainfoin. In addition, the data presented herein will provide valuable molecular information for genetic breeding and provide insight into the future study of flower color polymorphisms in sainfoin.


2018 ◽  
Vol 40 (3) ◽  
Author(s):  
Lixia Sheng ◽  
Wei Xia ◽  
Shu Zang ◽  
Yuqian Zeng ◽  
Xiaoyu Yuan ◽  
...  

2019 ◽  
Author(s):  
Anand Krishnan ◽  
Avehi Singh ◽  
Krishnapriya Tamma

AbstractAnimal color patterns function in varied behavioral contexts including recognition, camouflage and even thermoregulation. The diversity of visual signals may be constrained by various factors, for example, dietary factors, and the composition of ambient environmental light (sensory drive). How have high-contrast and diverse signals evolved within these constraints? In four bird lineages, we present evidence that plumage colors cluster along a line in tetrachromatic color space. Additionally, we present evidence that this line represents complementary colors, which are defined as opposite sides of a line passing through the achromatic point (putatively for higher chromatic contrast). Finally, we present evidence that interspecific color variation over at least some regions of the body is not constrained by phylogenetic relatedness. Thus, we hypothesize that species-specific plumage patterns within these bird lineages evolve by swapping the distributions of a complementary color pair (or dark and light patches in one group, putatively representing an achromatic complementary axis). The relative role of chromatic and achromatic contrasts in discrimination may depend on the environment that each species inhabits.


2019 ◽  
Vol 20 (19) ◽  
pp. 4743 ◽  
Author(s):  
Hongli Liu ◽  
Qian Lou ◽  
Junren Ma ◽  
Beibei Su ◽  
Zhuangzhuang Gao ◽  
...  

Grape hyacinth (Muscari spp.) is a popular ornamental plant with bulbous flowers noted for their rich blue color. Muscari species have been thought to accumulate delphinidin and cyanidin rather than pelargonidin-type anthocyanins because their dihydroflavonol 4-reductase (DFR) does not efficiently reduce dihydrokaempferol. In our study, we clone a novel DFR gene from blue flowers of Muscari. aucheri. Quantitative real-time PCR (qRT-PCR) and anthocyanin analysis showed that the expression pattern of MaDFR had strong correlations with the accumulation of delphinidin, relatively weak correlations with cyanidin, and no correations with pelargonidin. However, in vitro enzymatic analysis revealed that the MaDFR enzyme can reduce all the three types of dihydroflavonols (dihydrokaempferol, dihydroquercetin, and dihydromyricetin), although it most preferred dihydromyricetin as a substrate to produce leucodelphinidin, the precursor of blue-hued delphinidin. This indicated that there may be other functional genes responsible for the loss of red pelargonidin-based pigments in Muscari. To further verify the substrate-specific selection domains of MaDFR, an assay of amino acid substitutions was conducted. The activity of MaDFR was not affected whenever the N135 or E146 site was mutated. However, when both of them were mutated, the catalytic activity of MaDFR was lost completely. The results suggest that both the N135 and E146 sites are essential for the activity of MaDFR. Additionally, the heterologous expression of MaDFR in tobacco (Nicotiana tabacum) resulted in increasing anthocyanin accumulation, leading to a darker flower color, which suggested that MaDFR was involved in color development in flowers. In summary, MaDFR has a high preference for dihydromyricetin, and it could be a powerful candidate gene for genetic engineering for blue flower colour modification. Our results also make a valuable contribution to understanding the basis of color variation in the genus Muscari.


2018 ◽  
Vol 65 (4) ◽  
pp. 467-481 ◽  
Author(s):  
Jair E Garcia ◽  
Mani Shrestha ◽  
Scarlett R Howard ◽  
Phred Petersen ◽  
Adrian G Dyer

AbstractAngle dependent colors, such as iridescence, are produced by structures present on flower petals changing their visual appearance. These colors have been proposed to act as signals for plant–insect communication. However, there is a paucity of behavioral data to allow for interpretations of how to classify these colors either as a signal or a cue when considering the natural conditions under which pollination occurs. We sampled flowers from 6 plant species across various viewpoints looking for changes in the visual appearance of the petals. Spectral characteristics were measured with different instruments to simulate both the spectral and spatial characteristics of honeybee’s vision. We show the presence of color patches produced by angle dependent effects on the petals and the calyx of various species; however, the appearance of the angle dependent color patches significantly varies with viewpoint and would only be resolved by the insect eye at close distances. Behavior experiments with honeybees revealed that pollinators did not use angle dependent colors to drive behavior when presented with novel flower presentations. Results show that angle dependent colors do not comply with the requirements of a signal for plant–pollinator communication since the information transmitted by these colors would be unreliable for potential, free-flying pollination vectors. We thus classify angle dependent colors produced by micro- and ultra-structures as being a cue (a feature which has not evolved for communication), and observe no evidence supporting claims of these angle dependent colors having evolved as visual signal.


This chapter revisits the author's doctoral work on the maintenance of flower color variation in morning glories to explore how a feminist analysis can help explain the shape and scope of this research. It traces the idea of variation and the shifting understanding of its significance in the field of evolutionary biology and moreover posits that an interdisciplinary education would have fundamentally reshaped the author's work on the evolutionary biology of morning glory flower color variation. Thus, inspired by the touch-sensitive thigmatropic tendrils of morning glories, which allow the plants to scale large objects and burrow into narrow crevices, this chapter narrates tales of the morning glories through the curious and adventurous tendrils of naturecultural storytelling.


2021 ◽  
Author(s):  
Xiaobo Sun ◽  
Lisi He ◽  
Zhenhao Guo ◽  
Jiale Su ◽  
Xiaoqing Liu ◽  
...  

Abstract Rhododendron is an important woody ornamental plant and breeding varieties with different colors is vital research goal. In this study, a flower color variation cultivar ‘Yanzhi Mi’ (pink petals) and the wild-type (WT) cultivar ‘Dayuanyangjin’ (white petals with pink stripes) were used as research objects, the pigment and transcriptome of their petals during different flower development (stage S1, S2, S3, S4 and S5) were analyzed and compared. The results showed that the derivatives of cyanidin, peonidin and pelargonidin may be responsible for the pink of mutant petals and S2 stage (buds showing color at the top but with the scales still present) was the key stage of flower color formation of mutant. In total, 412,910 transcripts and 2,780 differentially expressed genes (DEGs) were identified in pairwise comparisons of WT and mutant petals. GO and KEGG enrichment analyses of the DEGs showed that the ‘DNA-binding transcription factor activity’, ‘Flavonoid biosynthesis’ and ‘Phenylpropanoid biosynthesis’ were more active in mutant petals. Early anthocyanin pathway candidate DEGs (CHS3-CHS6, CHI, F3Hs and F3’H) were strongly correlated and up-regulated expression in mutant petals than in WT petals at S2 stage. These genes may be the key structural genes for the pink coloration of mutant petals. In the petals of mutant, two R2R3-MYB unigene (TRINITY_DN59015_c3_g2 and TRINITY_DN49281_c1_g6) were identified as repressors involved in anthocyanin regulation and were significantly down-regulated at S2 stage. This study shed light on the biochemistry and genetic mechanisms underlying the flower coloration in two Rhododendron obtusum cultivars.


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