Variations in physiological, biochemical, and structural traits of photosynthesis and resource use efficiency in maize and teosintes (NADP-ME-type C₄)

Abstract

C 4 plants show higher photosynthetic capacity and resource use efficiency than C 3 plants. However, the genetic variations of these traits and their regulatory factors in C 4 plants still remain to be resolved. We investigated physiological, biochemical, and structural traits involved in photosynthesis and photosynthetic water and nitrogen use efficiencies (PWUE and PNUE) in 22 maize lines and four teosinte lines from various regions of the world. Net photosynthetic rate (P N) ranged from 32.1 to 46.5 μmol m −2 s −1. P N was positively correlated with stomatal conductance, transpiration rate, and chlorophyll, nitrogen and soluble protein contents of leaves, but not with specific leaf weight. P N was positively correlated with the activities of ribulose-1,5-bisphosphate carboxylase/oxygenase and the C 4-acid decarboxylases, NADP-malic enzyme and phosphoenolpyruvate carboxykinase, but not with the activity of phosphoenolpyruvate carboxylase. Leaf structural traits (stomatal parameters, leaf thickness, and interveinal distance) were not correlated with P N. These data suggest that physiological and biochemical traits are involved in the genetic variation of P N , but structural traits are not directly involved. PWUE is in the lower class of values reported for C 4 plants, whereas PNUE is in the highest class of values reported for C 4 plants. PNUE was negatively correlated with leaf nitrogen content but not significantly correlated with P N. PWUE was not correlated with δ 13 C values of leaves, indicating difficulty in using δ 13 C values as an indicator of PWUE of maize. In general, teosinte lines showed lower P N but higher PWUE than maize lines.

Structural and physiological responses of the C4 grass Sorghum bicolor to nitrogen limitation

“…Similar N responses of the enzymes were reported in some C 4 species such as maize (Sugiyama et al, 1984) and Amaranthus retroflexus (Sage et al, 1987). In another NADP-ME-type C 4 grass maize, Rubisco is a rate-limiting factor of photosynthesis but PEPC is not so (Usuda, 1984;Yabiku & Ueno, 2017). Therefore, it is reasonable that sorghum plants also cope with N limitation by lowering the allocation of N to PEPC more than to Rubisco.…”

“…stomatal density increased (Table 1). This negative relationship between the two has been found in other plants also (Franks et al, 2009;Tsutsumi et al, 2017;Yabiku & Ueno, 2017). It appears superficially that these morphological responses of stomata offset each other.…”

“…Because the photosynthetic tissue of C 3 plants is constituted of just M cells, the leaves can simply stack M cells with increasing N level, resulting in increased SLW and thicker leaves. However, the SLW of C 4 species falls within a narrow range, because C 4 leaves need both M and BS cells, which impose an anatomical constraint (Ghannoum et al, 2011;Tsutsumi et al, 2017;Yabiku & Ueno, 2017). In sorghum also, the magnitude of the N response of SLW was small (Figure 1(D)), but there was a positive correlation between P N and SLW (Figure 2(B)).…”

Light reacclimatization of lower leaves in C₄maize canopies grown at two planting densities

“…LMA was calculated by dividing dry mass by leaf area values. The N content of dried leaf samples (0.3 g) was determined by using a micro-Kjeldahl procedure (Yabiku and Ueno 2017).…”

High photosynthesis rate in the selected wild rice is driven by leaf anatomy mediating high Rubisco activity and electron transport rate

“…The importance of investigating variations in leaf photosynthesis within and across species to be exploited for sustainable increases in crop yield and productivity has been emphasized (Parry et al ., 2018; Adachi et al ., 2019; van Bezouw et al ., 2019). A number of studies have shown the variation in photosynthesis and related traits within species, such as maize (Yabiku & Ueno, 2017), wheat (Driever et al ., 2014), rice (Adachi et al ., 2014; Qu et al ., 2017), soybean (Gilbert et al ., 2011), and even C 4 species Gynandropsis gynandra (Reeves et al ., 2018). Extensive comparative genetic and genomic studies have been undertaken to investigate the variation in photosynthetic efficiency across C 3 and C 4 species (Bräutigam et al ., 2011; Külahoglu et al ., 2014; Wang et al ., 2014).…”