Dominant Trees in a Subtropical Forest Respond to Drought Mainly via Adjusting Tissue Soluble Sugar and Proline Content

Abstract

It is well-known that drought has considerable effects on plant traits from leaf to ecosystem scales; however, little is known about the relative contributions of various traits within or between tree species in determining the plant’s sensitivity or the tolerance to drought under field conditions. We conducted a field throughfall exclusion experiment to simulate short-term drought (∼67% throughfall exclusion during the dry season from October to March) and prolonged drought (∼67% throughfall exclusion prolonging the dry season from October to May) and to understand the effects of drought on two dominant tree species (Michelia macclurei and Schima superba) in subtropical forests of southern China. The morphological, physiological, and nutritional responses of the two species to the two types of drought were determined. There were significantly different morphological (leaf max length, max width, leaf mass per area), physiological (leaf proline) and nutritional (P, S, N, K, Ca, Mg) responses by M. macclurei and S. superba to prolonged drought. Comparison between the drought treatments for each species indicated that the trees responded species–specifically to the short-term and prolonged drought, with S. superba exhibiting larger plasticity and higher adaption than M. macclurei. M. macclurei responded more sensitively to prolonged drought in terms of morphology, proline content, and nutritional traits and to short-term drought with regard to soluble sugars content. The differential species-specific responses to drought will allow us to estimate the changes in dominant trees in subtropical forests of China that have experienced a decade’s worth of annual seasonal drought.

Intensified Precipitation Seasonality Reduces Soil Inorganic N Content in a Subtropical Forest: Greater Contribution of Leaching Loss Than N2O Emissions

“…Therefore, extending the dry season did not result in water stress that would restrict plant growth and N uptake. Moreover, a previous study conducted in the same forest as this study reported that extending the dry season increased the leaf N content of the dominant species (S. superba and M. macclurei; Kuang et al, 2017). This suggests that extending the dry season in this studied subtropical forest does not restrict plant N uptake, but may stimulate it by increasing the concentration of soil inorganic N.…”

Responses in Growth and Anatomical Traits of Two Subtropical Tree Species to Nitrogen Addition, Drought, and Their Interactions

“…To reduce osmotic potential, plants often accumulate osmolytes such as proline, soluble sugars, and amino acids ( Kuang et al, 2017 ; Li et al, 2020 ). Parallel with Ψ pd and Ψ md , N addition and drought increased the NSC concentrations, which was evidenced by significant increases in soluble sugar and starch in the leaves or xylem for both O. pinnata and S. superba .…”

Nitrogen Supply Alters Rice Defense Against the Striped Stem Borer Chilo suppressalis

“…The solution was then centrifuged at 8,000 g at 25°C for 10 min. The resulting supernatants were combined and analyzed using the anthrone–sulfuric acid method ( Kuang et al, 2017 ).…”