Leaves Adapt to Dry, Hot Conditions

photograph of white flowers with red lines

Biological Strategy

Kukumakranka plant

Image: B2KPhotography / Shutterstock / Some rights reserved

Regulate Cellular Processes

Cells are the basic building blocks of all living systems, so cellular processes dictate how physiological processes occur within those systems. Cells (whether entire unicellular organisms or parts of multicellular living systems) grow, metabolize nutrients (that is, chemically transform them), produce proteins and enzymes, replicate, and move. Cells as part of multicellular systems rarely act alone, instead having ways to signal to start and complete simple to quite complex interactions. How skin heals is a good example of the role of cellular processes. Blood cells called platelets release clotting factors to stop the bleeding; white blood cells rid the area of foreign materials and release molecules to coordinate healing; cells called fibroblasts start rebuilding using proteins called collagen; new blood vessels form; and skin cells called keratinocytes create the new surface.

Search this Function

Adapt Phenotype

Living systems evolve over time in response to selective pressures. Selective pressures are environmental factors that reduce the reproductive success of some individuals in a population. Genetic makeup (genotype) is one way in which living systems mitigate selective pressures, but another is adaptable phenotypes. A phenotype is an observable characteristic that can be thought of as the expression of the genotype, combined with modifications caused by the environment or developmental conditions. Individuals, populations, or ecosystems that have phenotypes capable of reducing the effects of selective pressures can survive. Some plants, for example, modify their leaf shape in response to changing environmental conditions. A single olive tree has variable leaf shapes on sunny compared to shady areas of the tree, yet the next year, those same buds may develop differently shaped leaves.

Search this Function

Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

Search this Living System

Leaves of the Kukumakranka plant adapt to dry, hot conditions and continue photosynthesis by keeping their stomata open.

Plants “breathe” or respire through their leaves by tiny adjustable openings in the leaves called stomata. The stomata enable carbon dioxide gas to enter the plant for . Oxygen and water vapor exit the leaves through stomata, as well. In many plants, when the outside temperature is warm and water evaporates more readily, plants close their stomata to prevent excessive water loss. Closing the stomata, however, can disrupt plant growth by preventing carbon dioxide from entering the leaves and thereby reducing photosynthesis.

A plant in South Africa called Kukumakranka (Gethyllis villosa) appears to have s within its leaves to help it survive the hot and semi-arid climate. G. villosa seems to keep many of its stomata open even in dry conditions, which helps the plant to continue to photosynthesize throughout the day. Exactly why G. villosa can maintain open stomata and not suffer from excessive water loss is currently unknown; however, researchers hypothesize that leaf chemistry and adaptations in the stomata help in the plant’s ability to adjust its response to dry conditions. An ability to continue to photosynthesize in warmer conditions could be beneficial as climate change influences the region.

Last Updated June 8, 2017

References

“During drought stress, the ability of leaf photosynthesis to adapt to dry conditions depends on a suite of alterations relating to leaf morphology, stomatal control and photochemistry. Under drought stress, G. villosa had a better photosynthetic performance than G. multifolia, which appears not to be related to foliar adaptations such as specific leaf mass (SLM), but to G. villosa‘s leaves maintaining their stomatal conductance (G_s), photosynthetic light compensation (LCP) and photon yields during the dry periods. Stomatal control of photosynthesis is a well-known adaptation in previous work from various ecosystems.” (Daniels et al. 2013:40)

“Since both bulbous species occur in a semi-arid area, which is being threatened by progressive aridity due to climate change and increased shading from invasive species, the aim of this work is to therefore investigate the capacity for photosynthetic adaptation of both species to these environmental changes.” (Daniels et al. 2013:37)

Journal article