2018 ASHS Annual Conference

Photosynthetically assimilated carbon (C) is transported form source leaves to stems and fruits depending on their development stage and environmental conditions. Knowledge about the effect of elevated air temperature and drought stress on photosynthetic assimilation and allocation is important for developing best crop management practices. To examine the translocation of assimilated C in fruit-bearing shoots throughout the development process, we constructed an in situ ¹³CO₂ exposure polyethylene bag for stems and fruits of a Chinese jujube cultivar 'Lingwuchangzao". We used an infrared radiation equipment to control simulating elevated temperature environment, an automatic irrigation system to control soil water levels and the method of ¹³C labeling to measure assimilation of ¹³C in leaves and its translocation to the stems and fruits. Fruit-bearing shoots were sampled 12h, 24h and 7days after exposure treatment, followed by analysis of ¹³C inventory in leaves, stems and fruits). We evaluated the translocation of ¹³C using nested design (two air temperature environment, and three soil water levels) and analyzed ¹³C remaining ratio and ¹³C distribution ratio. C（¹³C）in stem, leaf and fruit under elevated temperature condition were greater than under normal temperature, but gradually reduced with the intensified drought stress. The δ¹³C and C（¹³C）accumulation of every organ increased under elevated temperature and drought stress, but C（¹³C）accumulation decreased with the increase of drought stress. Elevated temperature increased photosynthates accumulation and δ¹³C values in different organs, but drought stress decreased this accumulation. The rank of photosynthates allocation in different organs of jujube cultivar 'Lingwuchangzao' was fruit > stem > leaf.