The fruit as the beginning of life

Cota-Sánchez and Abreu observed six Epiphyllum phyllanthus plants in a fragment of the Atlantic Forest on the University of São Paulo campus. Three plants produced four fruits. These were collected at different ages, from four to seven weeks. The two older fruits contained germinating seeds and developing seedlings. [Cota-Sánchez and Abreu 2007, pp.3866–3868]

The authors described cryptovivipary. The embryo begins growing within the fruit, and seedlings emerge through a naturally opening area of its wall. Roots and green cotyledons developed within the fruit tissues. Subsequent development retained the usual structure of a young cactus. [Cota-Sánchez and Abreu 2007, pp.3867–3869,Fig.1]

Three substrates for the offspring

Seedlings from the oldest fruit were divided into three groups of 29 plants. One group was placed on tree bark near the parent, another on the ground beside the same tree, and the third in sterile soil under a controlled photoperiod. This design compared the fate of a single offspring cohort after release from the fruit. [Cota-Sánchez and Abreu 2007, pp.3866–3867]

The first week brought the highest mortality in all treatments. Seedling loss subsequently slowed, and the number of remaining plants gradually stabilized. The small sample and shared origin from a single fruit define the scope of inference. The result documents the difficulty of moving from germination to independent growth. [Cota-Sánchez and Abreu 2007, pp.3868–3869,Fig.2]

Offspring development within maternal tissues

The fleshy fruit creates a local environment for germinating seeds. The authors associated its role with resource provision and moderation of conditions during the initial growth stage. They interpreted this system using the concepts of parental care and conspecific nursing. These are proposed ecological explanations of the observed phenomenon. [Cota-Sánchez and Abreu 2007, pp.3869–3871]

After release, a seedling must maintain contact with its substrate, take up water and develop photosynthetic organs. In a tree crown, available substrate is spatially limited and subject to changes in moisture. Vivipary observations show that germination onset and subsequent establishment are distinct stages of population biology. [Cota-Sánchez and Abreu 2007, pp.3869–3872]

Basis of the account

Based on the full text of an original research study.