Getting to the Roots Problem
Understanding plant roots requires
figuring out how they solve problems of physics
In biology, things don’t just happen without a plan. Two news items about roots reveal foresight, planning and engineering of programmed solutions.
What keeps plant roots growing toward gravity? Study identifies four genes (University of Illinois at Urbana-Champaign, 26 Sept 2022). Stems grow upward; roots grow downward. This ability, called gravitropism, doesn’t just happen. It takes 4 genes to make a root grow down, say scientists at University of Illinois—at least in corn and in the lab plant Arabidopsis, the two species they looked into.
When a germinating seed is turned on its side, some roots make a sudden, steep turn towards gravity, while others turn a fraction more slowly. The researchers used machine vision methods to observe subtle differences in root gravitropism in thousands of seedlings and combined that data with genetic information for each seedling. The result mapped the likely positions of gravitropism genes in the genome.
The article does not mention what these genes actually do. But a little reflection indicates that gravitropism is under programmed control. Genes are essentially software modules that command robots (proteins) to do a job—to perform a function.
The U of I team wanted to learn about gravitropism because growing plants in space, where there is no gravity, presents new challenges for a plant genome to solve without human help. “Plants are pretty discombobulated without gravity,” one researcher quipped.
The work can be valuable but the press release contains unnecessary references to evolution and deep time. It says tautologically that the two species “evolved about 150 million years apart in evolutionary history.” What other kind of history could they evolve in? Now that the university paid its pinch of incense to Caesar Darwin, the NASA funds can flow.
Plants defy gravity until they are dead. Sequoia log showing tree rings covering centuries of time. (DFC)
Plants rooted in rocks (Nature Geoscience, 6 Sept 2022). This article begins with a photo of a majestic tree with its roots gripping solid rock, but it’s not about how roots manage that feat. It’s another paean to evolution. Count the synonyms in red:
Plants came very late to the party of Earth’s evolution but have since substantially contributed to shaping today’s world. The first land plants, such as mosses and liverworts, arrived about 480 million years ago, bringing fundamental changes to biogeochemical cycles. These rootless plants quickly evolved over the next 50 million years or so, leading to the expansion of vascular plants with complex root systems. The development of root systems enhanced the stability and complexity of sedimentary systems, changing water flow and reshaping the landscape completely. Thus, Earth dramatically and fundamentally changed as plants evolved.
Without controversy, plants play a significant role in the biosphere, helping to break down solid rock material, absorb carbon dioxide, and sustain levels of atmospheric oxygen. How the complex interactions between plants and geology keep the world habitable and refreshing can be researched without the evolutionary storytelling.
The root problem in botany is evolution, with its philosophical roots embedded in deep time. How could a biosphere even exist without plants from the beginning? The second article assumes Earth wobbled between hothouse conditions and deep freezes. The world we know, however, stays within narrow temperature limits unknown anywhere else in the universe. These speak of foresight, planning and intelligent design.
Plants are amazing. They were the first organisms of creation. We should thank God for the green Earth he has given for our habitation, not make up stories that dress up the Stuff Happens Law with synonyms like evolved, arrived, developed, expanded, or emerged. Sink your life roots into the good soil where you can bear fruit for your Maker. “No one is established by wickedness, but the root of the righteous will never be moved” (Proverbs 12:3).