More efficient use of water
When discussing plants in general, the effects of an elevated concentration of CO2 were already known. The bibliographical references quoted by Robredo show that this is in fact so, since among other things, this elevated concentration increases biomass, root growth and total leaf area, and alters net photosynthesis rates and efficiency in water use. The so-called stomatal conductance is one of the keys, explains the researcher: "Stomata are pores that plants have in their leaves, and it is through them that they carry out the water and air exchange. When a plant is subjected to a high level of CO2, it closes its stomata to a certain degree. This causes the water to escape less, which is translated into greater efficiency in its use."
So a greater concentration of CO2 would appear to put the plants in an advantageous situation to address droughts. "If they use the water more slowly, they use it more efficiently and can grow over a longer period of time," explains Robredo. At least this is what she has been able to confirm in the case of barley. The results show that even though drought is harmful, its effect on barley is less when combined with an elevated concentration of CO2. In comparison with a situation in which an ambient level of this gas exists, its increase causes leaf and soil water content to fall less, the rates of photosynthesis to be maintained for longer, growth to be greater and the assimilation of nitrogen and carbon to be less affected. The researcher does in fact explain the importance of maintaining the balance between the nitrogen and the carbon: "Both the take-up of carbon and the assimilation of nitrogen have increased in a balanced way."
On the other hand, when irrigation is re-established in barley plants that have be
|Contact: Amaia Portugal|