Studying the root system of grapevine.

Root distribution and density determine the volume of soil available to the plant for water and nutrient uptake. Their knowledge is of practical relevance to choose the right combination of cultural practices necessary to meet appropriate yield and quality goals. Unfortunately, information on this topic is very often lacking or difficult to generalize. In fact, simple and exhaustive methods to study the roots in the field are not available. Moreover, the description of the root system given by the various methods are not easily comparable because the data are expressed in different units. In this paper, three methods of study are compared and an attempt is made to give a synthetic representation of root system useful to compare more easily different cases

Effect of water stress on canopy architecture of Capsicum annuum L.

Water stress affects growth of green pepper plant so that leaf number and area are reduced and canopy architecture modified. Implications on radiation regime of the canopy may be expected

Studies on water relations of grapevine (Vitis vinifera)

On stressed and non-stressed 3-year-old grapevines grown in 100 1 containers leaf water potential (LWP) and diffusion resistance (LR) were measured during July and August 1978. In non limiting soil water condition a linear correlation was found between LWP and the atmosphere water potential (AWP) at any time of the day, except at 10\u201311 am and 4\u20135 pm, when the plants were in a very unsteady status. At 7\u20138 am and 2\u20133 pm the regression lines were steeper than at the other times of the day. Explanations for that are given. In non limiting water condition LWP was also related with transpirational fluxes (TF), decreasing linearly with increasing fluxes. The stressed plants did not show any of these relationships. The stressed grapevines usually showed lower LWP even at early morning hours. With relatively high AWP the stressed vines maintained sometime LWP similar to that of non stressed plants, doubling LR and reducing dramatically TF, limiting therefore the gas exchanges. After irrigation the stressed plants recovered fairly rapidly. In fact after 90 min LWP was similar to that of non-stressed plants but LR was much higher suggesting a slow metabolic recovering. In July and August 1979 LWP and LR measurements were made on fruiting grapevines (FG) and on defruited plants (DG). FG showed a higher TF, because of a lower LR, but maintained LWP similar to that of DG, suggesting the importance of the fruit in the plant water balance either determining a more efficient water transport or acting as a capacitance

Caratterizzazione ecofisiologica e microclimatica delle leccete del Bosco della Mesola (FE)

In this work, which is part of a multidisciplinary study on the decay of a Mediterranean oak stand, Quercus ilex L. is characterized by several ecophysiological parameters regarding both the singlel plant and the complete forest. The performance of the single plant is described by leaf water potential, stomatal resistance and net photosynthesis. The behaviour of the community of plants is analysed by the evapotranspiration flux density. In a micrometeorological descriptuiion of a day, the ecological importance of dew is emphasized