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P.3 caption beneath table 1: "PH: plant height, FLA: flag leaf area, NCPP: number of culms per plant,
NSPS: number of spikelets per spike, SDM: spike dry matter, FLDM: flag leaf dry matter, KNPS: kernel number
per spike, KWPS: kernel weight per spike, RR: relative reduction." P.3 3rd paragraph: "Due to its high protein content [ref 38], durum wheat cultivar Svevo was selected for an RNA-seq experiment aimed at exploring the molecular response to chronic nitrogen starvation. Plants were grown under N standard or deficiency supply up to Z77 developmental stage. Nitrogen shortage caused serious changes in the phenotype, accelerating plant flowering time and senescence. As awaited, the whole plant growth was severely affected under nitrogen limitation [ref 39]: all the traits considered sensibly differed between plants grown in the two conditions (Table 1). In particular, stressed plants were shorter than control ones and the flag leaf area was sensibly reduced (68%), affecting also grain filling and yield [refs 27, 40]. This is consistent with a comparable significant reduction in the flag leaf dry matter. The most striking difference between the two groups of plants was, as expected, tiller number and development. In fact, while in the controls the average number of culms per plant was ≅4, the N starved plants generally did not tiller and showed a single culm. Consequently, also the yield traits were negatively influenced by N starvation. A significant reduction between normal and stressed plants was observed for the number of spikelets per spike (NSPS, over 34%), spike dry matter (SDM over 62%), and number of kernels per spike (KNPS, 75%). The average kernel weight per spike (KWPS) was 0.65 g in the control and 0.16 g in the stressed plants, with a reduction of ≅76% (Table 1). These results strongly support the previously formulated hypothesis that, when nitrogen is limited, a premature leaf senescence occurs affecting the rate and duration of protein accumulation in the seeds [ref 41]." |