UC Davis plant scientist proposes "Bloom cycle" to explain why seemingly wasteful plant processes are vital for life

Arnold Bloom's "Bloom cycle" reveals that photorespiration isn't wasteful but essential for plants to create proteins, DNA, and natural defenses.

By: AXL Media

Published: Mar 3, 2026, 5:21 AM EST

Source: The information in this article was sourced from University of California - Davis

Challenging the "wasteful" view of photorespiration

For decades, the scientific community has largely viewed photorespiration as an evolutionary glitch—a process that parallel to photosynthesis, releases carbon dioxide and consumes up to 30% of a plant's energy. Extensive research has been dedicated to "fixing" this perceived waste to boost agricultural yields. However, Arnold Bloom, a professor at the UC Davis Department of Plant Sciences, argues that plants would not have maintained an inefficient process over billions of years of evolution.

The role of the Bloom cycle in nitrogen conversion

Bloom’s research, published in Plant, Cell & Environment, introduces the "Bloom cycle." This pathway reveals that photorespiration is actually a critical engine for nitrogen assimilation. The cycle takes nitrogen absorbed from the soil and converts it into compounds necessary for survival, including proteins and DNA. Without this pathway, plants would be unable to produce the complex organic molecules required to grow and sustain life.

Defense mechanisms and nutritional quality

Beyond fundamental growth, the Bloom cycle is responsible for creating the specialized chemicals plants use to deter insects and resist disease. By coordinating the storage of energy in the form of sugars and organic acids, the cycle maintains the delicate balance between high crop yields and the nutritional density of the plant. This discovery suggests that efforts to eliminate photorespiration could inadvertently result in crops that are less nutritious and more vulnerable to pests.