Differences in water relations and total carbohydrate content between precommercially thinned and unthinned Pinus nigra subsp. pallasiana stands

Abstract

Variations in seasonal responses in water relations and total carbohydrate content (TCC) in one-yearold shoots from precommercially thinned (PCT) and unthinned Anatolian black pine stands were assessed during three seasons (sampling in May, July and September) in 2015–2017. Three different treatments were established: unthinned control with 4 941 stems·ha–1 and two thinned spacing levels (2–2.5 and 3–3.5 m) where 2 133 stems·ha<sup>–1</sup> and 1 093 stems·ha<sup>–1</sup> were left, respectively. Differences in osmotic potential at turgor loss point (Ψπ<sub>TLP</sub>) between the thinned and unthinned plots appeared only during a water shortage (September) in the second season, with the thinned stands showing lower Ψπ<sub>TLP</sub> than the unthinned stands. Seasonal variation in terms of Ψπ<sub>TLP</sub> was detected in the 3–3.5 m spacing trees. PCT were effective on osmotic potential at full turgor (Ψπ<sub>100</sub>), relative water content (RWC), symplastic water at saturated point per dry weight of the shoot and dry weight fraction. In both the thinned and unthinned plots, a gradual decline was observed in RWC from May to September in all three years. Generally, although TCC was found to be higher in the 3–3.5 m spacing, control plots were also high in carbohydrates in some periods. Results reflect the ability of this species to survive in changing environments by PCT during dry periods in the three studied seasons. Although PCT has an effect on water potential components and TCC, it is not clear exactly how effective the PCT density is in osmotic adjustment.

Differential of three fields grown Juniperus species summer drought and cold hardening

“…Plants with high Ɛmax are more drought tolerant (Ritchie and Schula, 1984). Ψ TLP varies from season to season (Mitchell et al, 2008;Deligöz et al, 2021). Differences in physiological responses to water deficiency show that alternative mechanisms According to the PCA analysis, RWC (r:0.854), TSS (r:0.621), Chla (r:-0.918), Chlb (r:-0.883), Total Chl (r:-0.933), mean air temperature (r:-0.921), and total precipitation (r:0.921) had the highest correlation with Axis 1 (52.8 %) (Fig.…”

“…Photosynthetic pigment content, which was generally low in the spring and winter, was high in the summer. Plants adjust chlorophyll content to adapt to environmental conditions (Bayar and Deligöz, 2021). Photosynthetic pigments usually increase at the end of the growing season.…”

Use of brassinosteroids to overcome unfavourable climatic effects on seed germination in Pinus nigra J. F. Arnold

“…The black pine was chosen for the experiment since the species is native to Southern Europe and parts of Central Europe (San-Miguel-Ayanz et al 2016), as well as in Turkey and parts of Central Asia (Ayan et al 2021, Deligoz et al 2021). The tree is widely used in forestry as its wood is durable and easy to process (Dias et al 2020).…”