Three to five-year-old peach trees (Prunus persica (L.) Batsch cv. 'Maycrest') grafted on P. 'Damas J869' grown in a sand t were removed in the spring and grown hydroponically for several months. The~ystem comprised two balances continuousl) recording the mass of the nutrient solution and that of the iree, so as to estimate transpiration and water uptake rates sepa Diurnal variation in plant water content (transpiration minus water uptake) was observed, with rapidly decreasing values w the solar radiation increased, while the reverse occurred when radiation decreased. Changes in stem diameter were continuo recorded using linear variable differential transducers. Data collected over several days of contrasting climatic conditions re that rapid changes in the stem diameter occurred throughout the day and were closely related to plant water content. A lag not exceeding 10 min was found between changes in stem diameter and plant water content. These results are discussed in r to the use of micromorphometric methods to control irrigation in fruit trees. Moreover. we give values for the water stored shoots which may contribute to the transpiration stream.
Vine leaf area index has a great impact on berry quality. Th is study was conducted to determine whether vine leaf area index could be estimated, and mapped through normalized diff erence vegetation index (NDVI) ground-based measurements. Th e NDVI measurements were performed using a Greenseeker (N-Tech Industires, Ukiah, CA and Oklahoma State Univ., Stillwater), pointed sideways at the vertical shoot positioned vines [Vitis vinifera (L.)] at Bordeaux, France. Canopy gap fraction and vertical leaf area index (VLAI) measurements were also performed. Plot NDVI maps were obtained by linking the GreenSeeker to a GPS during measurements. Th e NDVI delivered by the sensor was sensitive to the variations of vertical leaf area index and gap fraction of the canopy, that is, vine vigor. Th e GreenSeeker was successfully used to carry out a follow-up of the foliar growth of the vine, but with many precautions. Th e maps obtained showed relative variations of vigor at an intraplot level, enabling access to relevant information for better vineyard management.Abbreviations: LAI, leaf area index; NDVI, normalized diff erence vegetation index; PW, pruning weight; VLAI, vertical leaf area index.
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