Canopy structure, light interception, and photosynthetic characteristics under different narrow-wide planting patterns in maize at silking stage.

摘要

Planting pattern affects canopy structure of crops and influences other physiological characteristics such as light interception and radiation use efficiency. In the current paper, the effects of planting patterns on the canopy structure, light interception, and photosynthetic characteristics at silking stage of two maize (Zea mays L.) cultivars (Beiyu288 and Xianyu 335) were examined in three planting patterns narrow-wide rows of (1) 30 cm+170 cm (P1, 6.4 plants m-2), and (2) 40 cm+90 cm (P2, 6.4 plants m-2), and uniform row of 65 cm (control, i.e. CK, 6.4 plants m-2). The ratio of leaves perpendicular to rows was highest in P1 and the leaf orientation value in P1 was constant and slightly lower in P2 compared with that in CK. Although a decrease in the total intercepted photosynthetically active radiation (IPAR) of P1 was found in the two cultivars, more incoming PAR was detected at the middle-low canopy strata of P1. The apparent quantum yield and the net photosynthesis rate (P_N) in P1 and P2 were significantly higher than those in CK. The P_N and stomatal conductance (g_s) values in P1 were significantly higher than those in CK, and the intercellular CO₂ concentration decreased with an increase in P_N. These results indicated that narrow-wide row planting patterns improved the canopy structure, allowed more IPAR to reach the middle-low strata of the canopy, and enhanced the leaf photosynthetic characteristics of maize crops at silking stage compared with CK.