ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Why Do Some Plants Have Coloured Leaves?

Updated on November 8, 2023
Deepa damodaran profile image

Deepa is a freelance researcher and journalist. She writes and makes documentaries and videos.

Why Leaves Vie Flowers?

There are many leaves in the plant kingdom that defy the natural green to splash colors of all hues. Purple-leaved Fennel, Purple Passion Plant, Snake Plant, Calathea, Aluminium Plant, African mask plant, and the all-season crotons! All of them embellish themselves with colours so exotic that one cannot pass them by without noticing. It is common that the new shoots and leaves of many plants brightly parade in purple or red. The shoots however get clad in green as they grow. We all know that the plants bear multi-coloured flowers to attract pollen-carrying insects and birds to facilitate reproduction. However, the leaf colour does not have such a crucial role to serve. Nature has some very different purposes in mind, it seems.

The Purpose Served by Colour in Leaves

The shoots of many plants are either red or purple. The colour works as an invisible cloak that protects these delicate plant parts from sun damage. Anthocyanin is the pigment that gives leaves red or purple colour. It is the sunscreen of these newborn beauties and scientists believe that chlorophyll literally hides behind this mask to protect itself from sharp sunlight. There is still much ambiguity surrounding the reason why shoots or leaves of plants have colours other than green. One hypothesis is that the leaves that bask in strong sunlight are those that display non-green colours. Another theory is that anthocyanins are strong antioxidants and they help the plants to remain winter-ready. Then there are the tropical rainforest plants that have leaves with purple undersides the utility of which to the plant is still not clearly known.

Scientists say that the red or purple colour hides the shoots and leaves from the prying eyes of the predators which include pests as well as bigger herbivores. Studies have shown that red leaves get less devoured by herbivores when compared to green ones. Phenolic, which is a resin present in high concentrations in red or purple leaves, could be another reason why herbivorous insects and animals do not want to eat them. It is also postulated that purple undersides of certain tropical leaves have the same function- to protect them from fungal attacks, as it is a big threat in the humid microclimate of a tropical forest. The herbivorous insects are attracted to green colour than red or purple. Hence, colours other than green reduce insect attacks.

The differently coloured leaves still can carry out photosynthesis as efficiently as their green counterparts because they have a sufficient quantity of chlorophyll in them though masked by the colour pigments.

Chameleons of the Plant World

Come Fall, trees such as Maples, Aspens, and Sourwood literally start a riot of colours. It is basically in preparation for the ensuing period of dormancy made necessary by a hostile climate. What happens at the molecular level is that the anthocyanin pigment acts as a shade under which the chlorophyll is broken down and nitrogen from it is reabsorbed by the plant for surviving the hibernation time. There are also other factors that impact the fall colours of tree leaves such as temperature, humidity, and sunlight. Very low temperatures close to the freezing point in Autumn cause bright red colour in Maple leaves. A cloudy sky on the other hand will enhance the saturation of fall foliage colouration.

The Rainbow Effect of Leaf Colours

Different pigment combinations impart different shades to leaves. Good saturation of both anthocyanin and carotenoid results in brown colour. This is the case when the leaf is senile or fallen. Above all, based on the pH value of the anthocyanin pigment, the leaf exhibits colours ranging from red to blue. Bilirubin, the pigment that gives the yellow colour to the skin, eyes, (and urine of those who suffer from jaundice), is also present in some plants and gives a yellow hue to plant parts. For example, the seeds of the white Bird of Paradise plant have an orange-coloured fuzz on them, which is caused by Bilirubin.

The Leaves Age Gracefully

When the leaves age, they turn yellow or red. When a leaf reaches the end days of its life, the chlorophyll in it breaks down allowing the plant to absorb back the nitrogen in it. Obviously, nature does not want the leaf to leave the body of the plant with the saved-up chlorophyll wasted. It is almost like the leaf giving its vital force back to the plant and crossing the rainbow bridge in an ultimate act of self-sacrifice.

Gardener's Favourites, Nutrition Treasure Troves

The coloured plants are the favourites of any gardener. Science says that the variegated patterns on leaves, when they are just white and green, are caused by plant mutation. These plants are the albinos of the plant kingdom. And many of them are known air purifiers and make them an indoor gardener’s coveted possessions.

The amazing facts about leaf colour remind us that everything in nature has a purpose that will be revealed to a probing eye. Studying nature closely might thus give us an ability to understand better the purpose of our own lives and all the inter-connections involved.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Deepa

working

This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://corp.maven.io/privacy-policy

Show Details
Necessary
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Features
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Marketing
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Statistics
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)