Vivipary in plants is the fascinating phenomenon where seeds germinate while still attached to the fruit.
Vivipary is when seeds germinate in fruit. This is a natural occurrence and can happen to most types of plants. In fact, in some instances, it is actually an important part of the natural life cycle of the plant. Read on to find out more information including the definition of vivipary and in which plants it occurs most commonly.
What is vivipary?
Vivipary is a term originating from Latin that means ‘live birth’. In animals, vivipary is where offspring grow and develop in the womb and are birthed live. This is most common for mammals, but, while rare, can also occur in fish and reptiles. In plants, vivipary is the germination of seeds while still attached to the fruit, whether or not the fruit is still attached to the plant. Vivipary in plants can occur due to environmental factors or genetic mutations. Seed dormancy is related to levels of the two plant hormones, Abscisic acid (ABA) and Gibberellins. These two hormones work opposite to each other; ABA inhibits growth and seed germination, while Gibberellins, or Gibberellic acid (GA) facilitates seed germination and cell elongation. Concentrations of ABA in plant tissues are a direct response to moisture levels: the higher the moisture content of the tissue, the lower the ABA levels. Therefore, if low ABA levels occur, either due to genetic mutations or through excessive seed moisture levels, seeds may germinate while they are still attached to their fruit.
Tip: true vivipary in plants only occurs through sexual reproduction; the seeds germinate while still attached to the fruit. False vivipary is a type of vegetative reproduction where clones develop into plantlets while still attached to the parent plant.
What plants can be affected by vivipary?
Vivipary can occur in your kitchen or in your garden. A few of the most common viviparous plants are tomatoes (Solanum lycopersicum), apples (Malus domestica), citrus (Citrus spp.), strawberries (Fragaria × ananassa), corn (Zea mays), as well as squash and pumpkins (Cucurbita spp.). When vivipary occurs in fruit in your kitchen, the fruit containing the germinating seeds is fine to eat, it just may not look so appealing.
Tip: do not consume the seedlings from the viviparous fruit of nightshades like tomatoes and aubergines (Solanum melongena). Leaves and other vegetative growth of these plants can cause gastrointestinal complaints when consumed. However, as mentioned earlier, the fruit itself is safe to eat.
For some plant species, vivipary is utilised for the efficient distribution and establishment of new offspring. Vivipary for mangroves (Rhizophora spp. and Avicennia spp.), for example, ensures their offspring survive in their semi-aquatic tidal environment. On the other hand, some alpine plants utilise false vivipary to ensure their offspring survive the short growing period of high alpine environments.
Alpine bistort, Bistorta vivipara, is a perennial herb found throughout the northern hemisphere. By producing live offspring, it is perfectly adapted to high elevations and colder climates. In summer, leaves are produced at bulbils, which are swollen nodules on the lower portion of the inflorescence, which then quickly develop into new plants. These new plants then fall off to establish themselves before cold weather, ice, and snow can halt the growing process for the season. Technically, Bistorta vivipara reproduces through false vivipary as bulbils are vegetative propagules. In some climates with longer warmer growing seasons, the plant will also produce viable seeds from flowers on the upper portion of the inflorescence.
The red mangrove (Rhizophora mangle) and the grey mangrove (Avicennia marina) are both true viviparous plants. They produce fruit with long skinny seeds that germinate while still attached to the mother plant. This allows for rapid establishment in their intertidal environment once the germinated seed settles in its new home. The seedlings will float and can be carried by tidal currents for months until they finally reach a favourable location.
Vivipary, albeit unsightly at times, is an evolutionary advantage for many plants. Not been lucky enough to find a viviparous tomato yet? No matter, you can learn all you need to know about saving tomato seeds from your favourite fruit in our in-depth article on the subject.