Anderson Machado de Mello

Crescimento, desenvolvimento e retardamento da senescência foliar em girassol de vaso (Helianthus annuus L.): fontes e doses de nitrogênio

Sunflower is the fourth oil grain crop grown worldwide and some genotypes are used with ornamental purpose as cut and pot-grown flower. The objective of this study was to evaluate the effect of different sources and rates of nitrogen on some growth and developmental parameters, and on the delay of leaf senescence in pot-grown sunflower. An experiment was carried out inside a greenhouse in Santa Maria, RS, Brazil. Treatments were: urea, ammonium nitrate and calcium nitrate at rates of 0, 50, 100 and 150mg L-1 of N in the fertigation solution, with two weekly applications. The experiment was a two-factorial (sources and rates of N) in a completely randomized design with six replications. Each replication was a number 15 pot (1.5L, 15cm height) with one plant/pot. The variables analyzed were: final leaf number, final plant height, percentage of senescent leaves at selling stage and at the end of vase life, total leaf area per plant, phyllochron, and the thermal time from emergency to visible bud and from emergency to selling stage. The N source influences leaf area of pot-grown sunflower, with urea being recommend for higher leaf growth. The rate of around 100mg L-1 of N applied twice a week through fertigation promoted desirable characteristics for commercialization such as earliness and delay of leaf senescence.

Effect of 1-MCP applied at different times during cold and Ca storage

ABSTRACT - The objective of this work was to evaluate the effect of 1-MCP applied at different period during the cold storage (CS) and in controlledatmosphere (CA) on the quality of ‘Quioto’. Persimmon. The experimental design was completely randomized with four replication s of 30 fruits andthe tested treatments were: cold storage (CS), cold storage + 1-MCP (1000ppb) in the beginning of the storage, cold storage + 1-MCP (1000ppb) in theend of the storage period; storage in controlled atmosphere (CA) with 1kPa of O 2 and 5kPa of CO 2 and 1kPa of O 2 and 5kPa of CO 2 + 1-MCP in the endof the storage, after 2 months of storage at –0.5°C, plus 5 days at 10°C and 3 days at 20°C. In the cooled storage, the 1-MCP, applied as in thebeginning of the storage as in the end of the storage, provided greater pulp firmness. For the parameters: total soluble solids, rottenness anddarkening of the peel didn’t have statistics difference between the treatments. There were no statistics differences between th e treatments for totalsoluble solids, rottenness and darkning of the peel. In conclusion 1-MCP applied in the beginning or end of storage period mant ained high firmmness.