Root growth patterns in different pine species

INTRODUCTION

OBJECTIVE

P. sylvestris, P. nigra, P. pinaster, P. pinea and P. halepensis coexist in the Iberian Peninsula. These native species show an importantspatial segregation that correlates with geomorphological and climatic conditions (Alià et al. 1996; Prada et al. 1997; Barbero et al. 1998).The first two ones live in cold and mesic climates, in the highest parts of the highest mountain ranges of the Iberian Peninsula, while theothers grow in coastal drier Mediterranean environments.

The objective of the present work is to evaluate root growth and respiration patterns in front of seasonal temperature variations and wateravailability conditions, in order to clarify if and at which scale these will be determinants of future population and species spatial dynamics ina changing climate scenario.

The present work is focused on root growth dynamics and root systems respiration.Pines were planted in 2012 in Torre Marimon (Caldes de Montbui, Barcelona) facilities in sandy individual rhizotrons (0.36 m3) under tunnelconditions in order to avoid rainfall (Figure 1).Root length and vertical distribution were evaluated fortnightly by digital imaging adjusted with Gimp (GNU license) and measured withWinrhizo software (Regent Instrument Canada Inc). Root system respiration was measured with a portable LCi-SD Soil Respiration AnalysisSystem (ADC BioScientific Ltd).

METHODS

Figure 2. Monthly mean, maximun and minimum

temperature and reference evapotranspiration ±S.E.

Table 1. Total amount of water applied per plant, for

each year and irrigation treatment.

Figure 1. Rizotron

Year Dose 1 Dose 2

2012 128 98

2013 333 146

2014 111 58

TOTAL 572 302

Cumulate Irrigation (l·plant-1

)

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Zuccarini, P. , Grau, B., De Herralde, F., and Savé, R.Enviromental Horticulture Program. IRTA. (robert.save@irta.cat)

RESULTS

Figure 3. Evolution of total root length for each species, treatment and soil depth, at the middle and at the end of every season.

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Pinus nigra

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Pinus halepensisPinus pinaster Pinus pinea

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Pinus sylvestris

DOSE 2

DOSE 1

Figure 4. Evolution of soil respiration for each species and irrigation treatment. Means ±S.E are displayed.

Coastal pines show higher root length growth and deeper soil distribution than mountain pines (Figure 3).

A similar pattern can be detected for root respiration, which is clearly affected by water availability (Figure 4).

Growth and respiration values suggest this classification: P.halepensis > P.pinaster ≥ P. pinea >> P.nigra ≥ P.sylvestris

Root growth patterns, together with their hydraulic characteristics (Zuccarini et al 2014), can help to predict the potential distribution of thesespecies in Spain under future climatic change conditions.

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Pinus sylvestris Pinus nigra Pinus pinaster Pinus pinea Pinus halepensis

Alía R, Moro J, Denis JB. 1997. Performance of Pinus pinaster Ait. provenances in Spain: interpretation of the genotype-environment interaction. Can J Forest Res 27: 1548-1559.Barbero M, Loiesel R, Quézel P, Richardson M, Romane F. 1998. The role of desiccation tolerance in determining tree species distributions along the Malay-Thai Peninsula. Funct Ecol 22:221-231.Prada M, Gordo J, De Miguel J, Mutke S, Catálan G, Iglesias S et al. 1997. Las regiones de procedencia de Pinus pinea L. en España. Madrid: Ministero de Medio Ambiente; Organismo Autónomo ParquesNacionales.Zuccarini, P., Farieri, E., Vásquez, R., Grau, B. & Savé, R..2014. Effects of soil water temperature on root hydraulic resistance of six species of Iberian pines. Plant Biosystems - ID TPLB-2013-0440

REFERENCES