Drought periods and air warming.

<p>¹Mean number of weeks (± SE) per drought period with a continuous soil water content < 0.06 m^3.m^-3 at a soil depth from 0 to 25 cm in the D and AWD treatment, see [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126701#pone.0126701.ref010" target="_blank">10</a>] for details.</p><p>²Warming of daytime air temperature (8:00–18:00 h, UTC+1) (compared to the control), details see [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126701#pone.0126701.ref030" target="_blank">30</a>].</p><p>Drought periods and air warming.</p

Main effects table during the experimental periods of 2009.

<p>Difference among species, drought-rewetting-drought periods (1 = at the end of 1^stD period, 2 = after RW period and 3 = at the end of 2^ndD period) or differences versus control (<u>± </u>%) or calcareous versus acidic soil (<u>± </u>%); significant difference:</p><p>(*) <i>P</i> ≤ 0.1,</p><p>* <i>P</i> ≤ 0.05,</p><p>** <i>P</i> ≤ 0.01,</p><p>*** <i>P</i> ≤ 0.001;</p><p>ns = not significant <i>P</i> > 0.05;</p><p>na = not available, because foliar K concentrations were determined only at the end of 2^ndD period.</p><p>Main effects table during the experimental periods of 2009.</p

Supporting Data 020916

Supporting Data 02091

Foliar total amino acid-N of three oak species exposed to different climate treatments and soil types during a drought-rewetting-drought course.

<p>Vertical bar charts show mean and standard error and the bar charts were grouped for each species, in each treatment and soil type. Periods are indicated from left to right side: white bar = the first drought period (1^stD), hedged bar = the rewetting period (RW), cyclone bar = the second drought period (2^ndD). Different small letters indicate significant differences across three oak species within each climate treatment, period and soil type. Different capital letters indicate significant differences across different climate treatments for each species, period and soil type. Greek symbols indicate significant differences across the different drought-rewetting-drought periods for each species, climate treatment and soil type. Asterisks indicate significant differences between acidic and calcareous soil within each climate treatment, species and time course (<i>P</i> ≤ 0.050).</p

Changes in the Dynamics of Foliar N Metabolites in Oak Saplings by Drought and Air Warming Depend on Species and Soil Type

<div><p>Climate change poses direct or indirect influences on physiological mechanisms in plants. In particular, long living plants like trees have to cope with the predicted climate changes (i.e. drought and air warming) during their life span. The present study aimed to quantify the consequences of simulated climate change for foliar N metabolites over a drought-rewetting-drought course. Saplings of three Central European oak species (i.e. <i>Quercus robur</i>, <i>Q</i>. <i>petraea</i>, <i>Q</i>. <i>pubescens</i>) were tested on two different soil types (i.e. acidic and calcareous). Consecutive drought periods increased foliar amino acid-N and soluble protein-N concentrations at the expense of structural N in all three oak species. In addition, transient effects on foliar metabolite dynamics were observed over the drought-rewetting-drought course. The lowest levels of foliar soluble protein-N, amino acid-N and potassium cation with a minor response to drought and air warming were found in the oak species originating from the driest/warmest habitat (<i>Q</i>. <i>pubescens</i>) compared to <i>Q</i>. <i>robur</i> and <i>Q</i>. <i>petraea</i>. Higher foliar osmolyte-N and potassium under drought and air warming were observed in all oak species when grown on calcareous versus acidic soil. These results indicate that species-specific differences in physiological mechanisms to compensate drought and elevated temperature are modified by soil acidity.</p></div

Foliar Glycine (Gly)-N of three oak species exposed to different climate treatments and soil types during a drought-rewetting-drought course.

<p>Vertical bar charts show mean and standard error and the bar charts were grouped for each species, in each treatment and soil type. Periods are indicated from left to right side: white bar = the first drought period (1^stD), hedged bar = the rewetting period (RW), cyclone bar = the second drought period (2^ndD). Different small letters indicate significant differences across three oak species within each climate treatment, period and soil type. Different capital letters indicate significant differences across different climate treatments for each species, period and soil type. Greek symbols indicate significant differences across the different drought-rewetting-drought periods for each species, climate treatment and soil type. Asterisks indicate significant differences between acidic and calcareous soil within each climate treatment, species and time course (<i>P</i> ≤ 0.050).</p

Foliar Glutamine (Gln)-N of three oak species exposed to different climate treatments and soil types during a drought-rewetting-drought course.

<p>Vertical bar charts show mean and standard error and the bar charts were grouped for each species, in each treatment and soil type. Periods are indicated from left to right side: white bar = the first drought period (1^stD), hedged bar = the rewetting period (RW), cyclone bar = the second drought period (2^ndD). Different small letters indicate significant differences across three oak species within each climate treatment, period and soil type. Different capital letters indicate significant differences across different climate treatments for each species, period and soil type. Greek symbols indicate significant differences across the different drought-rewetting-drought periods for each species, climate treatment and soil type. Asterisks indicate significant differences between acidic and calcareous soil within each climate treatment, species and time course (<i>P</i> ≤ 0.050).</p

Foliar total N of three oak species exposed to different climate treatments and soil types during a drought-rewetting-drought course.

<p>Vertical bar charts show mean and standard error and the bar charts were grouped for each species, in each treatment and soil type. Periods are indicated from left to right side: white bar = the first drought period (1^stD), hedged bar = the rewetting period (RW), cyclone bar = the second drought period (2^ndD). Different small letters indicate significant differences across three oak species within each climate treatment, period and soil type. Different capital letters indicate significant differences across different climate treatments for each species, period and soil type. Greek symbols indicate significant differences across the different drought-rewetting-drought periods for each species, climate treatment and soil type. Asterisks indicate significant differences between acidic and calcareous soil within each climate treatment, species and time course (<i>P</i> ≤ 0.050).</p

C:N ratio in leaves of three oak species exposed to different climate treatments and soil types during a drought-rewetting-drought course.

<p>Vertical bar charts show mean and standard error and the bar charts were grouped for each species, in each treatment and soil type. Periods are indicated from left to right side: white bar = the first drought period (1^stD), hedged bar = the rewetting period (RW), cyclone bar = the second drought period (2^ndD). Different small letters indicate significant differences across three oak species within each climate treatment, period and soil type. Different capital letters indicate significant differences across different climate treatments for each species, period and soil type. Greek symbols indicate significant differences across the different drought-rewetting-drought periods for each species, climate treatment and soil type. Asterisks indicate significant differences between acidic and calcareous soil within each climate treatment, species and time course (<i>P</i> ≤ 0.050).</p

A case study on nitrogen nutrition of native and introduced forest tree species in the Qinling Mountains, China

<p>The manuscript entitled "A case study on nitrogen nutrition of native and introduced forest tree species in the Qinling Mountains, China" was submitted to Frontiers in Plant Science. The attached raw data for root N, C uptake and soil parameters analyses are supplied and uploaded for matching the additional data available policy for future readers.</p