Physiological response of amaranth (Amaranthus caudatus L.) to plant density under deficit irrigation

摘要

In order to evaluate the effects of water deficit and plant density on some physiological characteristics and biological yield of amaranth (Amaranthus caudatus L.), a factorial experiment was conducted based on Randomized Complete BlockDesignwith three replications at the University ofTabriz in 2013. Treatmentswere irrigation intervals (I1 and I2: irrigations after 70 and 140 mm of evaporation from classApan, respectively) and plant densities (40000, 80000 and 120000 plants/ha). The results showed significant interaction of irrigation × plant density for leaf chlorophyll a, b, total chlorophyll, carotenoid, proline, relativewater content (RWC), photosystem éé efficiency (Fv/Fm) and biological yield. All chlorophyll content and biological yield increasedwith increasing plant density under water deficit. This increase was largely attributed to increased leaf thickness. Efficiency of photosystem éé has positive correlation with relative water content and biological yield. The highest (41230.60 kg/ha) and lowest (14820.03 kg/ha) biological yield were respectively obtained from120000 and 40000 plants/ ha under deficit irrigation.