How Does Light Intensity Affect the Elementary Fiber Length in Flax?

Abstract

There are not enough antecedents about the effect of a decrease in photosynthesis on flax stem growth and elementary fiber length. Therefore, plots sowed with cultivar Diane were shaded with nets that intercepted 70% of photosynthetically active radiation. The nets were placed at three stages of the growth period: S1: 575°Cd (height: 25 cm), S2: 854°Cd (height: 54 cm), and S3: 1304°Cd (height: 84 cm). These applications resulted in stems shadowed only in the parts, which grew during the treatment. Additionally, control plots without shadows during the entire cycle (S0) were grown. In every treatment the production of fiber was quantified, and a harvest index (HI = fiber biomass obtained/stems biomass produced) was calculated. Fiber quality was also evaluated using elementary fiber length. The harvest index was bigger in control plants than shadow plants. The length of elementary fiber of the shadow treatments S1, S2, and S3 was 4.28 cm, 3.76 cm, and 3.02 cm, respectively, whereas the adjacent portions to the shaded one in each treatment had a length fiber increase of 21%, 34%, and 37%, respectively. In the same portions, S0 had fiber lengths of 4.94, 4.45, and 3.82 cm, respectively. The trend observed in all the shaded treatments showed a decrease of elementary fiber length. The fiber length in the adjacent portions to the shaded ones was not conditioned by the shadow treatment received. These results allow relating fiber quality with stresses generated by meteorological events that take place during the growth of the stem.

Key Words:

• Elementary fiber
• light intensity
• flax