Introduction to Plant Nutrition

Discuss the common nutritional needs of plants

Plants obtain food in two different ways. Autotrophic plants can make their own food from inorganic raw materials, such as carbon dioxide and water, through photosynthesis in the presence of sunlight. Green plants are included in this group. Some plants, however, are heterotrophic: they are totally parasitic and lacking in chlorophyll. These plants, referred to as holo-parasitic plants, are unable to synthesize organic carbon and draw all of their nutrients from the host plant.

Plants may also enlist the help of microbial partners in nutrient acquisition. Particular species of bacteria and fungi have evolved along with certain plants to create a mutualistic symbiotic relationship with roots. This improves the nutrition of both the plant and the microbe. The formation of nodules in legume plants and mycorrhization can be considered among the nutritional adaptations of plants. However, these are not the only type of adaptations that we may find; many plants have other adaptations that allow them to thrive under specific conditions.

Left photo shows a dark green seedling with three leaves. The seedling is growing on a plot of dark-brown soil. Right photo shows a variety of red, orange, green and yellow squashes.

Figure 1. For this (a) squash seedling (Cucurbita maxima) to develop into a mature plant bearing its (b) fruit, numerous nutritional requirements must be met. (credit a: modification of work by Julian Colton; credit b: modification of work by “Wildfeuer”/Wikimedia Commons)

Cucurbitaceae is a family of plants first cultivated in Mesoamerica, although several species are native to North America. The family includes many edible species, such as squash and pumpkin, as well as inedible gourds. In order to grow and develop into mature, fruit-bearing plants, many requirements must be met and events must be coordinated. Seeds must germinate under the right conditions in the soil; therefore, temperature, moisture, and soil quality are important factors that play a role in germination and seedling development. Soil quality and climate are significant to plant distribution and growth. The young seedling will eventually grow into a mature plant, and the roots will absorb nutrients and water from the soil. At the same time, the aboveground parts of the plant will absorb carbon dioxide from the atmosphere and use energy from sunlight to produce organic compounds through photosynthesis. This module will explore the complex dynamics between plants and soils, and the adaptations that plants have evolved to make better use of nutritional resources.

What You’ll Learn to Do

  • List the elements and compounds required for proper plant nutrition
  • Describe how symbiotic relationships help autotrophic plants obtain nutrients
  • Describe how heterotrophic plants obtain nutrients

Learning Activities

The learning activities for this section include the following:

  • Nutritional Requirements
  • Autotrophic Plants
  • Heterotrophic Plants
  • Self Check: Plant Nutrition