Avaliação do estado nutricional do nitrogênio em batateira por meio de polifenóis e clorofila na folha

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito de doses de N sobre índices fisiológicos relacionados à nutrição nitrogenada e verificar a possibilidade de estimar indiretamente os teores foliares de N em batata. Foram avaliados os índices de flavonóis (IFLV), de clorofila (ICHL) e de balanço de N (IBN), e as estimativas dos teores foliares de N foram realizadas aos 21 e 42 dias após a emergência, por meio do medidor portátil Dualex. O experimento foi conduzido de novembro de 2010 a fevereiro de 2011, em delineamento de blocos ao acaso, e os tratamentos consistiram de cinco doses de N (0, 50, 100, 200 e 300 kg ha -1 de N, na forma de ureia) aplicadas em pré-plantio, com quatro repetições. Houve aumento no ICHL e no IBN e decréscimo no IFLV com o aumento das doses de N. Os índices determinados com o medidor Dualex correlacionaram-se com os teores de N e de clorofila extraível na quarta folha, bem como com o rendimento de tubérculos na safra. O Dualex pode ser utilizado para avaliar o estado nutricional de N em batateira e prognosticar a produtividade de tubérculos.Termos para indexação: Solanum tuberosum, avaliação em tempo real, balanço nutricional, clorofila, compostos fenólicos, flavonóis. Evaluation of potato nitrogen status based on polyphenol and chlorophyll leaf contentAbstract -The objective of this work was to evaluate the effect of N rates on physiological indexes related to nitrogen nutrition in potato, and to verify the possibility of indirectly estimating leaf N contents. Flavonol (FLVI), chlorophyll (CHLI), and the nitrogen balance (NBI) indexes were evaluated, and estimations of leaf N contents were made at 21 and 42 days after emergence using the Dualex leaf-clip instrument. The experiment was carried out from November 2010 to February 2011, in a randomized complete block design, with five N rates (0, 50, 100, 200, and 300 kg ha -1 of N, applied as urea) at pre-planting, and four replicates. There was an increase in CHLI and NBI and a decrease in FLVI with the increasing N doses. The indexes determined with Dualex were correlated with N and extractable chlorophyll content in the fourth leaf and with potato tuber yields. Dualex can be used to evaluate N nutritional status in potato plants, and for the prognosis of final tuber yield with readings.

Evaluation of the Non-destructive Method Efficiency of Estimating Nitrogen Content in Jambu Plants Grown in Hydroponic System

“…In research developed by Pôrto et al (2014), involving nitrogen fertilization in tomatoes, it was noted a trend of linear increase in the SPAD index as a function of the N doses applied. Other studies present results similar to those obtained in this research for this variable, in some crops, such as lettuce (Mendonza-Tafolla et al, 2019) and kaki (Choi et al, 2011) and potato (Coelho et al, 2012). Mampholo et al (2018), when working with two lettuce cultivars, observed that the total chlorophyll content in the leaves of these vegetable crops increased as the N supply in the soil increased.…”

“…The SPAD index indirectly quantifies the chlorophyll contents in leaves in loco (Milagres et al, 2019). Studies have demonstrated that SPAD units possess direct relation with N and chlorophyll contents in leaves of vegetables cultures, as potato (Coelho et al, 2012), the zucchini (Pôrto et al, 2011) and the lettuce (Mendonza-Tafolla et al, 2019). Thus, proving that the N content has been estimated by SPAD units in plants (Lee et al, 2019;Mendonza-Tafolla et al, 2019), it is proposed as a primary hypothesis that the SPAD index can be a value that evaluates the status of N in jambu leaves.…”

Chemical characteristics of fruits of two species of Physalis under nitrogen fertilization

“…When N limits growth of plants, there is an accumulation of carbohydrates in their tissues, according to the carbon/nutrient balance hypothesis (Bryant et al, 1983), thus this accumulation directs carbon to the synthesis of secondary metabolites (Hamilton et al, 2001), which seems to occur in Physalis. Coelho et al (2012) also observed a decrease in the concentration of total phenolics with increasing level of N in leaves of potato plants, following a quadratic model.…”

Top-dressing nitrogen management decision in potato using the UFV-80 color chart and SPAD readings

“…N concentration and critical N dilution curve have been used as destructive techniques. Nondestructive techniques based on leaf reflectance have been proposed as robust alternative and simple methods for pigment quantification in leaves (Silva et al, 2009;Busato et al, 2010;Coelho et al, 2012). The most commonly used equipment for the evaluation of N nutritional status in real time are: the analysis of the N-NO 3 content in the sap of the petiole using microelectrode (Brink et al, 2002) and the indicator strip selected for nitrate (Parks et al, 2012).…”

“…Additionally, SPAD chlorophyll meter readings have been shown to correlate well to laboratory-extracted chlorophyll (León et al, 2007), and to N status in culture of lettuce (Fontes et al, 1997), wheat (Tremblay et al, 2010), potato (Gil et al, 2002;Silva et al, 2009, Busato et al, 2010, tomato (Fontes and Araujo, 2006) and rice (Cabangon et al, 2011). Other equipment have been used as a tool to evaluate N nutritional status are Dualex ® (Coelho et al, 2012) and the digital camera (Li et al, 2010;Wang et al, 2014). Furthermore, the chlorophyll meter conducts fast readings without destroying leaves; however, it has relatively elevated costs for the small farmer (Fontes and Araujo, 2007).…”