Photosynthetically active radiation is required for seedling growth promotion by volcanic dacitic tuff breccia (Azomite)

Authors: McCue, Kent; MEHLFERBER, ELIJAH - University Of California; REED, ROBERT - I-Cultiver; ORTIZ, ALEXIS - I-Cultiver; FERREL, JON - Azomite Mineral Products, Inc; KHANNA, RAJNISH - I-Cultiver

Submitted to: Plant Direct
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2023
Publication Date: 12/1/2023
Citation: Mc Cue, K.F., Mehlferber, E., Reed, R., Ortiz, A., Ferrel, J., Khanna, R. 2023. Photosynthetically active radiation is required for seedling growth promotion by volcanic dacitic tuff breccia (Azomite). Plant Direct. 7(12). Article e537. https://doi.org/10.1002/pld3.537.
DOI: https://doi.org/10.1002/pld3.537

Interpretive Summary: The successful growth of a plant depends upon selection of the appropriate variety for the location and the correct agricultural inputs for maximum yield. There is still much to learn about the interactions of the plant and its environment and requirements for optimal yield. This study examined the effect of volcanic ash fertilizer on early seedling growth. In these experiments we utilized Arabidopsis, as well studied member of the cabbage and mustard (Brassica) family that includes many crop plants such as broccoli, cabbage and canola. Seedlings were germinated under different conditions in the presence or absence of multiple concentrations of ash fertilizer. Increased growth, measured by seedling height and cotyledon width, was observed with the addition of the ash fertilizer in the presence of light capable of promoting photosynthesis. The results indicate light was required for the plants to benefit from the ash fertilizer addition. These methods may also be useful to examine the activity of additional nutrient inputs on plant growth. With this system the mechanism of the plant’s response can be studied to gain insights into efficient nutrient applications for sustained crop production.

Technical Abstract: A plant’s growth and development are shaped by its genome and the capacity to negotiate its environment for access to light, water, and nutrients. In agriculture, crops are often planted at high densities and treated with excessive amounts of fertilizers to maximize yields, but often this leads to increased plant shading and unintended environmental consequences from fertilizer overflow. There is a vital need to better understand the interactions between the plant, its physical environment, and the nutrient fertilizers used in agriculture. In this study, a commercially available volcanic ash fertilizer, Azomite®, was tested for its effect on promoting early seedling vigor. Early growth and photomorphogenesis processes are well studied in Arabidopsis. Seedling assays under different light and dark conditions were used to dissect the underlying mechanisms involved. These assays have been well established and can be translated to agriculturally important crop plants. The volcanic ash fertilizer was tested at different concentrations on seedlings grown in continuous dark (Dc), Far-Red (FRc), Red (Rc), Blue (Bc), and White Light (WLc) on basic media lacking sucrose. Micronutrients in the volcanic ash significantly increased seedling growth under Rc, Bc, and WLc, but not under Dc and FRc, indicating that photosynthetically active radiation (PAR) was required for the observed growth increase. These data suggest that light triggers the ability of the seedling to utilize volcanic ash micronutrients. The methods described can establish mechanisms of activity of various nutrient inputs, coupled with whole-genome expression profiling, leading to better insights into nutrient field applications in crop production.