Using Light to Improve Commercial Value

The plasticity of plant morphology has evolved to maximize reproductive fitness in response to prevailing environmental conditions. Leaf architecture elaborates to maximize light harvesting, while the transition to flowering can either be accelerated or delayed to improve an individual's fitness. One of the most important environmental signals is light, with plants using light for both photosynthesis and as an environmental signal. Plants perceive different wavelengths of light using distinct photoreceptors. Recent advances in LED technology now enable light quality to be manipulated at a commercial scale, and as such opportunities now exist to take advantage of plants' developmental plasticity to enhance crop yield and quality through precise manipulation of a crops' lighting regime. This review will discuss how plants perceive and respond to light, and consider how these specific signaling pathways can be manipulated to improve crop yield and quality

Crescimento, acúmulo de nutrientes e produtividade da cultura da couve-flor

A couve-flor é uma das principais hortaliças cultivadas no Brasil. O conhecimento do crescimento e acúmulo de nutrientes pela cultura poderá ser útil no seu manejo e na adubação. Com o objetivo de determinar o acúmulo e a exportação de nutrientes pela cultura da couve-flor 'Verona', conduziu-se um experimento em solo, no período de 23 de fevereiro a 05 de junho de 2006. O delineamento do experimento foi em blocos casualizados com três repetições. O experimento constou inicialmente de 480 plantas divididas em três blocos. Para cada época de amostragem foram retiradas duas plantas por bloco. Foram realizadas cinco amostragens da parte vegetativa das plantas a cada 14 dias após o transplante e três amostragens das inflorescências a cada quatro dias, após o início de sua formação, sendo avaliado o crescimento da planta e o acúmulo de nutrientes nas inflorescências, no caule, nos limbos foliares e nos pecíolos. As plantas apresentaram crescimento e acúmulo de massa seca contínuos. O período de maior acúmulo de nutrientes foi do início da formação da inflorescência até a colheita. A ordem decrescente dos nutrientes acumulados pela cultura foi: N>K>Ca>S>Mg>P>Fe>Mn>Zn>B>Cu. A exportação de nutrientes (g por planta de macronutrientes e mg por planta para micronutrientes) pelas inflorescências foi de 3,50 de N; 0,296 de K; 0,06 de Ca; 0,290 de S; 0,032 de Mg; 0,249 de P; 2,08 de Fe; 0,375 de Mn; 1,01 de Zn; 1,45 de B e 0,07 de Cu.The cauliflower is one of the main vegetables grown in Brazil. The study of growth and nutrients accumulation by cauliflower could be useful for its fertilization. Therefore, a research was conducted in the field to determine the nutrients accumulation by 'Verona' cauliflower, from February 23 to June 5, 2006. The experiment consisted initially of 480 plants divided into three blocks. For each period two plants per block were collected. Five samples of the vegetative part were collected each 14 days after transplantation and three samples of inflorescences were collected every four days after the beginning of the cauliflower formation. Also, plant growth and nutrient accumulation in the inflorescences, stem, leaves and petioles were evaluated. Plants showed linear increase of growth and accumulation of dry matter. The greatest accumulation period occurred from the beginning of the inflorescence formation up to the harvest. The decreasing order of accumulated nutrients was: N>K>Ca>S>Mg>P>Fe>Mn>Zn>B>Cu. The export of nutrients (g per plant of macronutrients and mg per plant of micronutrients) by inflorescences was 3.50 of N; 0.296 of K; 0.06 of Ca; 0.290 of S; 0.032 of Mg; 0.249 of P; 2.08 of Fe; 0.375 of Mn; 1.01 of Zn; 1.45 of B and 0.07 of Cu