Samara Sibelle Vieira Alves

Comparação de métodos de mensuração de área foliar para a cultura da melancia

The leaf area determination is very important in agronomic and physiologic studies, for supplying information on vegetal metabolism, and the techniques used should be simple, fast and accurate. This study aimed to compare different methods for measuring leaf area in the watermelon crop. For that, the accuracy of four measuring methods was evaluated (experiment 1) and leaf area was compared by using the integration method provided by the LI-COR ® model LI 3100 equipment, at 0, 30, 60, 90, and 120 minutes, after being determined with the aid of a scanner (experiment 2). For the experiment 1, a completely randomized design, with four treatments and 19 replications, was used. The treatments were equivalent to the Leaf area integrator AM 300, Leaf area integrator LI-COR ® model LI 3100, Leaf discs, and Digital image analysis (scanner) methods, and were compared to the reference method (scanner), in accordance with the linear correlation coefficient (r). For the experiment 2, a randomized blocks design, with six treatments and ten replications (leaves), was used, with each leaf being considered a block and their average compared by using the Tukey test at 5%. Differences were observed for leaf area estimation according to the method employed. The leaf discs method was considered the most accurate one, for the watermelon crop, and the LI-COR ® model 3100 is not recommended for this crop, particularly when readings are made at longer intervals.

Qualidade de cenouras em diferentes densidades populacionais

Foi objetivo avaliar os efeitos de diferentes espacamentos de plantio sobre a qualidade de raizes de tres cultivares de cenoura nas condicoes de Mossoro, Rio Grande do Norte. O delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial 6 x 3, com tres repeticoes, sendo o primeiro fator constituido pelos espacamentos: 20 x 4, 20 x 6, 20 x 8, 15 x 4, 15 x 6 e 15 x 8 cm e o segundo, pelos cultivares: Brasilia, Alvorada e Esplanada. As caracteristicas avaliadas nas raizes de cenoura foram: comprimento da raiz, diâmetro da raiz, comprimento do xilema, diâmetro do xilema, solidos soluveis (SS), acucares totais, acidez total (AT), vitamina C, relacao SS/AT e pH. Nao houve interacao significativa entre cultivares e espacamentos de plantio em qualquer das caracteristicas avaliadas. Os espacamentos influenciaram o comprimento e diâmetro da raiz e o comprimento e diâmetro do xilema. O cultivar Alvorada sobressaiuse nos solidos soluveis, acucares soluveis totais e relacao SS/AT.