Title of article :
Growth response of three globose cacti to radiation and soil moisture: An experimental test of the mechanism behind the nurse effect
Author/Authors :
Alejandra Mart?nez-Berdeja، نويسنده , , Teresa Valverde، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Pages :
9
From page :
1766
To page :
1774
Abstract :
Cactus seedlings often establish under nurse plants which modify environmental conditions by increasing moisture and decreasing solar radiation, which may cause beneficial and detrimental effects, respectively, on seedling growth. Three soil moisture treatments (5%, 25% and 60%) and two solar radiation levels (100% exposure=243 μmol m−2 s−1, and 40%=102 μmol m−2 s−1) were used in a factorial design to analyze seedling growth response of three rare cactus species (Mammillaria pectinifera, Obregonia denegrii and Coryphantha werdermannii). The variables evaluated were relative growth rate (RGR), root/shoot ratio (R/S), and K (RGRroots/RGRshoot), obtained from an initial seedling harvest (6-month-old seedlings) and a final harvest 6 months after treatment application. All three species had slow RGRs (0.002–0.012 g g−1 day−1). O. denegrii had the lowest RGR values, but was the only species for which R/S and K varied with soil moisture. While all seedlings responded markedly to soil moisture, no response was observed to radiation treatments. The latter might have been related to the relatively low solar radiation levels present in the greenhouse. Yet, our results suggest that the main benefit nurse plants offer to seedlings is the increase in soil moisture.
Keywords :
Biomass allocationGrowth analysisPhenotypic plasticityRare speciesSeedling establishment
Journal title :
Journal of Arid Environments
Serial Year :
2008
Journal title :
Journal of Arid Environments
Record number :
764138
Link To Document :
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