PJB-2018-323
A test of the carbon starvation hypothesis in shrubs during drought-induced mortality
Quan Qiu, Junhui Wang, Yan Su, Jianwei Ma, Jiyue Li and Qian He
Abstract
The carbon starvation hypothesis is one of the current leading hypotheses in the mechanism of plant mortality, although it has not been verified due to lack of evidence. To provide a basis for the verification of carbon starvation hypothesis in plant mortality, we tested the role of the non-structural carbohydrate (NSC) reserves of three shrub species (Sarcozygium xanthoxylon, Berberis diaphana and Sophora moorcroftiana) during drought-induced mortality. NSC concentration ([NSC]) and content in the seedlings of three shrub species were determined during the cessation of photosynthesis and death and in well-watered controls. Our results show that drought induces NSC loss in three shrub species at death, and carbon starvation appears to occur after the cessation of photosynthesis. Differences among species exist during water stress regarding [NSC] dynamics in roots, stems and leaves, which appear to be caused by differences in drought resistance and NSC allocation strategy (root, stem, or leaf). Our data also show that survival time correlates with the size (biomass yield) and priority of NSC supply (growth or metabolism and defence), specifically, the shrub which had the biggest size and prioritized growth during drought was observed to have shortest survival time. Overall, our findings demonstrate that drought may cause a loss of NSC reserves leading to carbon starvation, and eventually death.
To Cite this article:
Qiu, Q., J. Wang, Y. Su, J. Ma, J. Li and Q. He. 2019. A test of the carbon starvation hypothesis in shrubs during drought-induced mortality. Pak. J. Bot., 51(6): DOI: http://dx.doi.org/10.30848/PJB2019-6(30)
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