Researchers Investigate Leaves for Longer Crop Roots

A novel method could simplify the selective breeding of crop plants for improved and deeper root systems. This non-invasive technique entails rapidly assessing a plant’s leaves to determine the depth of its roots in the soil.

Plants possessing extensive root systems demonstrate greater resilience to drought compared to those with shallow roots. The elongated roots of these plants can access groundwater reserves unreachable by shorter roots, enhancing their ability to withstand dry conditions.

Moreover, they demonstrate superior nutrient absorption, particularly of elements like nitrogen, which rainfall or irrigation typically transports deep into the soil.

Deeper Roots and Greenhouse Gas Mitigation

Additionally, deeper roots contribute to mitigating greenhouse gases, as the carbon dioxide absorbed by the plant remains sequestered in the soil for an extended period.

This occurs as CO2 is absorbed by the leaves and transported downward to the roots. Given these advantages, agricultural researchers are continually striving to cultivate new strains of crop plants with deeper root systems.

The conventional approach to assess root length involves excavating multiple plants from a trial plot and measuring their roots manually using a tape measure. However, this approach involves demanding and time-consuming tasks, and it prevents further measurements of the roots of the same plants as they are not replanted.

Enter LEADER, an acronym for “Leaf Element Accumulation from DEep Root,” developed by Prof. Jonathan Lynch and his team at Pennsylvania State University.

Harnessing Soil Mineral Distribution for Root Measurement

This technique capitalizes on the heterogeneous distribution of minerals and elements throughout the soil of a farm field. As roots penetrate the soil, they assimilate these substances, which are subsequently transported to the leaves.

Hence, by detecting the presence of specific soil elements in the leaves, it becomes feasible to gauge the depth of root growth. However, it is essential to initially identify the distribution of elements at different depths, a task accomplished by collecting and analyzing an initial soil core sample from the field under investigation.

Field Testing of LEADER System on Diverse Corn Lines

Lynch’s team grew 30 diverse corn lines across four US sites, monitoring soil and leaves for six years. On-site leaf analysis, using a handheld X-ray fluorescence spectrophotometer, matched traditional root-measurement accuracy for plants with roots over 30 cm (1 foot) long.

In cases where soil element divisions aren’t clear, a “tracer element” like strontium can be used to indicate root depth. LEADER, while tested on corn, is adaptable to various plants.

Lynch highlighted its importance, saying, “To breed deeper-rooted crops, you need to look at thousands of plants. Digging them up is expensive and time-consuming because some roots are down two meters or more. Everybody wants deep-rooted crops – but until now, we didn’t know how to get them.”

Read the original article on: New Atlas

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