The aim of the present work was to assess the physiological state of plants and photosynthetic apparatus activity in lettuce (Lactuca sativa L.) by non-invasive methods (leaf diffuse reflectance spectroscopy and chlorophyll fluorescence) under the deficiency of one of the macronutrients (nitrogen, phosphorus, or potassium). Our experiments assessed the deficiency of each of the macronutrients relative to plants vegetating under optimal nutrition. The used methods showed that the deficiency of macronutrients causes changes in the optical characteristics of lettuce plants (cvs. ‘Vitaminnyi’ and ‘Kokarda’), including a decrease in the chlorophyll content (57% and 51%) and a change in metabolism, which leads to a decrease in the efficiency of light energy conversion in photochemical processes of photosynthesis and an increase in the dissipation of excess light energy (19% and 10%). Linear regression equations, describing the relationship between net productivity and spectral characteristics of diffuse leaf reflectance with high accuracy, have been obtained. Changes in all studied indicators of the physiological state of plants under the influence of macronutrient deficiency are more pronounced at the early stages of development than in later periods, when the first symptoms of aging appear (decrease in ChlRI). The observed differences between lettuce cultivars and their response to nitrogen, phosphorus, or potassium deficiency are non-specific and mainly represent quantitative variation. The method for assessing the spectral characteristics of diffuse reflection of leaves seems to be the most promising for monitoring the physiological status of plants and early detection of nitrogen, phosphorus, or potassium deficiency.

Spectral characteristics of leaves diffuse reflection in conditions of soil drought: a study of soft spring wheat cultivars of different drought resistance | Dmitriy Rusakov, Elena Kanash | Agricultural Journals

Quantitative trait loci (QTL) mapping of diffuse reflectance indices of laminas in bread wheat ( Triticum aestivumL.) has been first performed under controlled conditions of a regulated...

Quantitative trait loci (QTL) of agriculturally valuable traits of soft spring wheat ( Triticum aestivumL.) were mapped in two simultaneous and independent experiments that were carried out in...

Creating an optimal light environment for different crops is crucial for achieving high yields under controlled environment agriculture conditions. Currently, there are no optimal technologies, including lighting technologies, for growing root crops (in particular radish) in CEA (Controlled Environment Agriculture). This study examined the effects of HPS (High-pressure sodium vapor lamps) and three original sunlike full-spectrum LED lamps on the morphophysiological characteristics and the diffuse reflectance indices of the leaves of two contrast radish cultivars. It was found that a higher blue light content (24%) in the spectrum of the LED 3 lamp contributed to the formation of radish plants with a more compact leaf rosette and maximum yield of roots (up to 19%) compared to the other two types of LED lamps. When treated with LED 3, photosynthesis efficiency was probably higher compared to LED 1 and LED 2, which led to a significant decrease in reflected radiation, especially in the blue and red ranges (by 5–143% and 32–86%, respectively). It was found that the genotype had a significant effect on all morphophysiological parameters of radish, while lighting treatment only affected the integral parameters (Pr—proportion of root crop, and Ai—attraction index) and leaf thickness. However, lighting treatment exhibited a greater impact on leaf reflection indices compared to the genotype, especially those related to chlorophyll content. The results of the study indicate that LED 3 lamps, simulating natural light at midday, are suitable for the production of radish root crops under CEA conditions.