Drought tolerance of wild versus cultivated tree species of almond and plum in the field

Abstract

Trees of the genus Prunus produce some of the most widely consumed fruits globally. The combination of climate change-related warming and increased drought stress, scarcity of freshwater resources for irrigation, and increasing demands due to population growth creates a need for increased drought tolerance in these tree species. Recently, we have shown in the field that a native wild pear species performs better under drought than two cultivated pear species. Here, a comparative field study was conducted in Israel to investigate traits associated with drought tolerance in almond (cultivated Prunus dulcis (Mill.) D. A. Webb vs wild Prunus ramonensis Danin) and plum (cultivated Prunus domestica L. vs wild Prunus ursina Kotschy). Measurements of xylem embolism and shoot and root carbon reserves were done along a year, including seasonal drought in the wild and a 35-day drought experiment in the orchards. Synchronous measurements of native xylem embolism and shoot water potential showed that cultivated and wild almond trees lost ~50% of hydraulic conductivity at −2.3 and −3.2 MPa, respectively. Micro-CT images confirmed the higher embolism ratio in cultivated versus wild almond, whereas the two plum species were similar. Dynamics of tissue concentrations of nonstructural carbohydrates were mostly similar across species, with higher levels in cultivated versus wild plum. Our results indicate an advantage for the wild almond over its cultivated relative in terms of xylem resistance to embolism, a major risk factor for trees under drought stress. This result is in line with our previous experiment on pear species. However, the opposite trends observed among the studied plum species mean that these trends cannot be generalized. It is possible that the potential for superior drought tolerance in wild tree species, relative to their cultivated relatives, is limited to wild species from dry and hot habitats.

Combined drought resistance strategies and the hydraulic limit in co-existing Mediterranean woody species

“…The two above reports resulted from extreme climate events, while the species in our study seem to confront severe drought every year. Recent studies on Prunus ramonensis and Pyrus syriaca also reported potential embolism in nature (Paudel et al, 2019a; Paudel et al, 2019b). Taking a modeling approach, Benito et al (2018) use minimum soil water potential data and HSMs of 44 European woody species and found that negative HSMs explain the mortality of 15 species at the driest margins of their distribution.…”

“…The two above reports resulted from extreme climate events, while the species in our study seem to confront severe drought every year. Recent studies on Prunus ramonensis and Pyrus syriaca also reported potential embolism in nature (Paudel et al, 2019a;Paudel et al, 2019b).…”

Relationships between xylem embolism and tree functioning during drought, recovery, and recurring drought in Aleppo pine

“…The vulnerability curve we show in Figure 6 represents an "empiric" curve, meaning it is constructed from Ψ x and PLA values that were measured simultaneously on naturally dehydrating intact plants rather than cut branches, similar to what was done in Paudel et al (2020) and Gerbi et al (2022). The P 50 (i.e., the Ψ x in which 50% of the xylem is embolized) was similar (<0.5 MPa difference) to the P 50 that was found for multiple populations of Aleppo pine from Israel (David-Schwartz et al, 2016), France (Davi et al, 2020), or Spain (Morcillo et al, 2022) using the Cavitron, meaning that the fast method (Cavitron) provides functional data that is relevant for naturally dehydrating trees.…”

Comparative analysis of drought resistance of plum cultivar-rootstock combinations in dry steppe conditions

“…The development of intensive gardening is facilitated by the use of low-growing clonal rootstocks that regulate the growth, development and productivity of the fruit plant [2][3][4]. A variety of rootstock forms, a huge selection of zoned, constantly updated varietal composition of fruit crops allows you to choose varietal-rootstock combinations for various growing conditions [5][6][7].…”