Genetic Variation in Response to N, P, or K Deprivation in Baby Leaf Lettuce

Abstract

Lettuce harvested at the baby leaf stage is a popular component of mixed salads in ready-to-use packages. Little is known, however, about response of baby leaf lettuce to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Eight lettuce accessions were subjected to five fertilization treatments to investigate genetic differences in reaction to N, P, and K fertilization. The control treatment provided optimal levels of macronutrients for plant growth, while other treatments deprived plants of either N, P, or K. Potassium deprivation had no obvious effect on plant weight or composition, apart from substantially decreased potassium content. Nitrogen and phosphorus deprivations, however, extensively decreased fresh weight and affected plant composition. Phosphorus and nitrogen deprivation considerably increased anthocyanin content in red-colored accessions, but anthocyanin was decreased in dark green-colored accessions, indicating differences in regulation of anthocyanin biosynthesis. Correlations between fresh weight, chlorophyll, anthocyanin, nitrogen, phosphorus, and potassium content were substantially affected by selection of datasets used for analyses; some relationships were revealed when analyzed separately by individual treatments, while others were more likely to be detected when analyzed by individual accessions. Absolute (ΔABS) and relative (2ΔREL) parameters described in this study were suitable for detecting over- and underperforming accessions. The ΔABS identified the absolute Lb-fold (logarithm to the base of 2, binary logarithm) change in performance of an accession in a treatment as compared to its performance in control conditions. The 2ΔREL parameter showed relative Lb-fold change for an accession as compared to the overall mean of ΔABS values of all accessions tested in control and treatment conditions.

Examining Phosphorus Use Efficiency Across Different Lettuce (Lactuca sativa L.) Genotypes

“…Many of the previous studies on PUE were conducted in greenhouses and in other cropping systems different to the one in this research. In L. sativa, genetic variability exists for nitrogen (N) use e ciency (Macias-González et al 2021) and this species reacts differently to the deprivation of P, N, or potassium (K) (Hoque et al 2010;Simko, 2020). Findings from the present study indicate the possibility to improve lettuce cultivars for PUE.…”

Predictive Modeling of a Leaf Conceptual Midpoint Quasi-Color (CMQ) Using an Artificial Neural Network

“…The approach could also be used to model ‘customized’ leaf colors [ 49 ] in environments where both leaf surfaces are not observable. For example, when the abaxial color of prostrate leaves cannot be seen on plants grown in controlled-environment agriculture (indoor farms), but knowing that color is important to the industry, concentrations of pigments for a particular cultivar could be modeled [ 10 ] from nutrition [ 50 ], temperature [ 19 ], light [ 51 , 52 ] and other environmental data, while the adaxial color of leaves can be measured with overhead sensors. CMQ coordinates (calculated from modeled concentrations of pigments using formulas provided in this study) can then be applied, together with adaxial color data, to estimate abaxial leaf color.…”

Insights into Nitrogen Metabolism in the Wild and Cultivated Lettuce as Revealed by Transcriptome and Weighted Gene Co-Expression Network Analysis.

“…Earlier studies have documented the effect of low nitrogen on physiological processes including low photosynthetic CO 2 assimilation and decreased photosynthetic rate (Terashima and Evans, 1988;Rascher et al, 2000;Carmo-Silva et al, 2015), and also reduced nitrogen (Lawlor et al, 1987) and phosphorus (Simko, 2020) content in leaves. In addition, insu cient nitrogen can affect photosynthetic pigments (Xiaochuang et al, 2017), activity of Rubisco proteins (Kumagai et al, 2014;Carmo-Silva et al, 2015), and chlorophyll uorescence (Carmo-Silva et al, 2015).…”

“…It also plays a pivotal role in regulation of several biological process like carbon metabolism, amino acid metabolism and protein synthesis (Jin et al, 2015). Nitrogen starvation impacts several major physiological and biological processes in plants affecting growth and development (Xu et al, 2012), root architecture (Zhang and Forde, 1998), lignin content (Peng et al, 2008), anthocyanin, phosphorus, and potassium content (Simko, 2020), chlorophyll synthesis (Bi et al, 2005), senescence, photosynthesis (Tantray et al, 2020), and CO 2 assimilation (Jin et al, 2015). Therefore, to increase crop yields, application of nitrogen fertilizers has dramatically increased in recent decades (Xu et al, 2012).…”