Diagnóstico do estado nutricional de n em porta-enxertos de citros, utilizando-se de teores foliares de clorofila

Abstract

The objective of this work was to evaluate chlorophyll content (a+b) on ‘Cravo’, ‘Cleópatra’, ‘Sunki’, ‘Volkameriano’ and ‘Tângelo Orlando’ rootstocks in tubes using as indicator on diagnosis by increasing N doses (0; 400; 800; 1,600; 3,200; 4,800 mg N/dm3 of substrate). The chlorophylls content presented righ positive correlation to height, diameter, aerial portion and roots dry matter mass, foliar area and NO3-N content for aerial portion, indicating that the total chlorophyll content can be used as indicator to diagnose N in citrus rootstocks cultivated in tubes. The maximum chlorophylls content estimated in rootstocks ‘Tangelo-Orlando’, ‘Cravo’, ‘Volkameriano’, ‘Cleópatra’ e ‘Sunki’ occurred in doses 1,461; 2,386; 2,494; 1,444; and 2,284 (mg N/dm3 of substrate), respectively. Total foliar chlorophyll content adequate for rootstocts of ‘Tangelo Orlando’ showed to be placed between 1.80 to 3.00 mg of total chlorophyll/dm2 of leaf at 120 days after sowing, for lemon ‘Cravo’ between 2.46 to 3.94 while the ‘Volkameriano’ showed to be placed between 2.27 to 4.23 mg of total chlorophyll/dm2 of leaf. Adequate values for foliar contents for total chlorophyll for Cleopatra tangerine showed to be 3.29 to 4.00 mg of total chlorophyll/dm2 of leaf while for ‘Sunki’ tangerine the values showed to be 1.80 to 3.16 mg of total chlorophyll/dm2 of leaf.