
%0 Journal Article
%A Noquet, Carine 
%A Avice, Jean-Christophe 
%A Ourry, Alain 
%A Volenec, Jeffrey J. 
%A Cunningham, Suzanne M. 
%A Boucaud, Jean 
%T Effects of environmental factors and endogenous signals on N uptake, N partitioning and taproot vegetative storage protein accumulation in <emph type="2">Medicago sativa</emph>
%J Functional Plant Biology
%D 2001/04/05
%V 28
%N 4
%P 279-287
%K Medicago sativa L., methyl jasmonate, N availability, N partitioning, regulation, short day, temperature, VSP accumulation.
%R https://doi.org/10.1071/PP00122
%U https://www.publish.csiro.au/paper/PP00122 
%X Our objectives were to study the regulation of N partitioning within tissues of non-nodulated alfalfa (Medicago sativa L.) and N storage in taproots as vegetative storage proteins (VSP) of 15, 19, and 32 kDa and &#946;-amylase (57 kDa) by environmental (photoperiod, temperature, N availability) and endogenous factors (methyl jasmonate). When compared to long-day conditions (LD, 16 h day/8 h night), short-day (SD, 8 h day/16 h night), exposure to low temperature (5&#x02DA;C) or application of methyl jasmonate (MeJA, 100 M ) for 35 d reduced the biomass shoot/ root ratio and modified the source&#8211;sink relationships for N. SD and MeJA treatments resulted in partitioning of N to taproots and a concomitant accumulation of VSPs. In comparison with LD, SD treatment also stimulated &#946;-amylase gene expression 2.5-fold. Although low temperature increased the N partitioning to root tissues and the accumulation of soluble proteins in taproot, VSP concentration and &#946;-amylase mRNA levels remained low. Increasing N concentration from 1 to 5 mM KNO3 doubled the total dry matter but did not affect the N partitioning within the plant, VSP accumulation, or &lsquor; &#946;-amylase expression. These results suggested that short photoperiod can result in preferential N allocation toward taproots with a concomitant induction of VSP accumulation. 
