Difference Between Leguminous and Non Leguminous Plants

The key difference between leguminous and non leguminous plants is that nitrogen-fixing bacteria in leguminous plants are from the genus Rhizobium, while nitrogen-fixing bacteria in non-leguminous plants are from the genus Frankia.

Leguminous plants belong to the flowering plant family Fabaceae or Leguminosae. They bear a dehiscent fruit called a pod or legume. Non-leguminous plants are from other plant families. They produce different types of fruits. Both leguminous and non leguminous plants have root nodules. They contain nitrogen-fixing bacteria. Nitrogen-fixing bacteria in leguminous plants belong to the genus of Rhizobium. In contrast, nitrogen-fixing bacteria in non-leguminous plants belong to the genus of Frankia.

CONTENTS

1. Overview and Key Difference
2. What are Leguminous Plants
3. What are Non Leguminous Plants
4. Similarities Between Leguminous and Non Leguminous Plants
5. Side by Side Comparison – Leguminous vs Non Leguminous Plants in Tabular Form
6. Summary

What are Leguminous Plants?

Leguminosae or fabaceae is a family of flowering plants. In fact, it is the third-largest flowering plant family. It is also known as the pea family or legume family. There are more than 18,000 species in this family. This family of plants are characterized by their compound leaves, which are pinnately compound, and a typical fruit called legume or pod. Most legumes are dehiscent fruits.  These dry fruits split open along two seams in order to release seeds to the environment.

Leguminous plants are mostly perennial or annual herbs. There are leguminous trees, shrubs and vines as well.  The majority of leguminous species are economically and agriculturally important. Soybeans (Glycine max), garden peas (Pisum sativum), peanuts (Arachis hypogaea), lentil (Lens culinaris), chickpea (Cicer arietinum), beans (Phaseolus) and alfalfa (Medicago sativa) are some of the most important commercial leguminous species. Leguminous plants and their products show a vast range of uses.  Many species provide foods and drinks. Certain species are used as pharmaceuticals and biofuels. Moreover, they are used in construction, textiles, furniture and crafts, paper and pulp, mining, manufacturing processes, chemicals and fertilizers, waste recycling, horticulture, pest control, and ecotourism.

There are three subfamilies of leguminous plants as Papilionoideae, Caesalpinioideae and Mimosoideae. Mimosoideae is a subfamily of leguminous plants. Leguminous plants have root nodules. Papilionoideae has the highest proportion of nodulating species. Nitrogen-fixing bacterial species (Rhizobia) form root nodules in leguminous plants. It is a symbiotic association or a symbiotic nitrogen fixation. It is estimated that agriculturally important leguminous plants species produce (fix) 40 to 60 metric tons of nitrogen annually. It is very important in soil improvement. Therefore, many leguminous plants are used as soil improvers and stabilizers in reforestation programmes.

What are Non Leguminous Plants?

Non-leguminous plants are plants from other plant families except the plant family Leguminosae. In simple words, non leguminous plants are not legumes. Similar to leguminous plants, some non-leguminous plants bear nodules containing nitrogen-fixing bacteria. Nitrogen-fixing bacteria are from the genus Frankia. They are actinomycetes. These plants can also fix nitrogen.

Several examples of non-leguminous nitrogen-fixing plants include alder trees and shrubs (Alnus sp.), bayberry and sweet gale (Myrica sp.), and sweet-fern (Comptonia peregrina). Moreover, they have arbuscular mycorrhizal fungi living symbiotically with them. But, unlike leguminous plants, the phosphorus requirement is lower in non-leguminous plants. In addition to these, they contain less amount of nitrogen than legumes.

What are the Similarities Between Leguminous and Non Leguminous Plants?

• Majority of leguminous plants and certain non leguminous plants have root nodules.
• Therefore, they are able to fix atmospheric nitrogen.
• Moreover, in both leguminous and non-leguminous plants, arbuscular mycorrhizal fungi can be seen.

What is the Difference Between Leguminous and Non Leguminous Plants?

Leguminous plants are members that belong to the flowering plant family Fabaceae while non-leguminous plants are plants of other flowering plant families except Fabaceae. The key difference between leguminous and non leguminous plants depends on the type of nitrogen-fixing bacteria. Nitrogen-fixing bacteria in leguminous plants belong to the genus Rhizobium, while nitrogen-fixing bacteria in non-leguminous plants belong to the genus Frankia.

The below infographic presents the difference between leguminous and non leguminous plants in tabular form.

Summary – Leguminous vs Non Leguminous Plants

Leguminous plants belong to the plant family Fabaceae. Non-leguminous plants belong to other plant families. Both leguminous and non-leguminous plants can fix atmospheric nitrogen since they contain nitrogen-fixing bacteria. However, the key difference between leguminous and non leguminous plants is the nitrogen-fixing bacteria. In leguminous plants, nitrogen-fixing bacteria belong to the genus of Rhizobium. But, in non-leguminous plants, nitrogen-fixing bacteria belong to the genus of Frankia.

Reference:

1. Scheublin, Tanja R, et al. “Nonlegumes, Legumes, and Root Nodules Harbor Different Arbuscular Mycorrhizal Fungal Communities.” Applied and Environmental Microbiology, American Society for Microbiology, Oct. 2004, Available here.
2. “Fabaceae.” Wikipedia, Wikimedia Foundation, 20 Mar. 2021, Available here.

Image Courtesy:

1. “Manjati” By Dinesh Valke (CC BY-SA 2.0) via Flickr
2. “Alnus glutinosa. Umeru” By SABENCIA Bertu Ordiales – Bertu Ordiales y Guillermo César Ruiz. Guía de los árboles d'Asturies. Ediciones Trabe. (2007) (CC BY-SA 4.0) via Commons Wikimedia