Figure 1.

Experimental Design and Physiological Responses of Rice Seedlings to Pi Deprivation and Resupply.

(A) Schematic representation of the experimental design. Seeds were germinated in water for 2 d and then transferred to a Pi-sufficient hydroponic (0.320 mM) solution for 2 weeks before being either transferred to Pi-deficient media (0 mM) or maintained in Pi-sufficient solution for 21 d. After 21 d of treatment, half of the Pi-starved plants were supplied with Pi-sufficient media for up to a day.

(B) Morphological appearance of rice seedling grown for 21 d on Pi-sufficient or -deficient media. Bar = 5 cm.

(C) to (G) Fresh weight (FW) ([C] and [D]) and Pi concentration ([F] and [G]) were assessed for shoots and roots. Root-to-shoot biomass ratio is represented (E).

(H) Relative expression of Pi starvation–responsive genes MGD2, PT6, and SPX2, in the roots. Expression levels are relative to the +Pi condition.

Errors bars are sd and n = 10, except for (H), where n = 3. Asterisk indicates statistically significant (P < 0.05) differences between samples grown under +Pi and –Pi conditions.