How plant water status affects the structure of proleptic shoots of almond trees

Proleptic shoots have different vegetative and reproductive characteristics that can be affected by water availability; however the potential effects on shoot structure have been difficult to quantify. The aim of this study was to investigate how plant water status affects the structure or patterns of axillary meristem fates and flowering along proleptic shoots of almond trees. Hidden semi-Markov models were built for shoots growing on trees under two irrigation rate treatments. The shoot structures in each treatment were modeled with 7-state models corresponding to seven distinctive zones along the shoots. The transition probabilities between zones as well as the probability of axillary meristem fates and of the number of flower buds per node were not affected by irrigation treatments. Only one intermediate zone (fourth zone) along the shoots developed fewer nodes with the low irrigation rate. The central zones of shoots appear to be the most affected by factors such as mild water stress that reduce the growth or vigour of shoots. (Resume d'auteur)