Invasive Species Compendium

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Abstract

Resistance response of five afforestation tree species under drought stress.

Abstract

Objective: To select species for afforestation in difficult sites by evaluating the drought resistance of five native and alien tree species. Methods: Pot experiments were conducted to study the physiological response and drought resistance of l-year-old seedlings of Liquidambar formosana, Pistacia chinensis, Ulmus elongata, Kaelreuteria bipinnata, and Quercus texana under conditions of appropriate humidity and light, moderate. and severe drought (75%-80%, 55%-60%, 40%-45% and 30%-35% of the soil field capacity). Result: With the increase of drought extent, five species showed different levels of symptoms of drought stress and major symptoms are yellow leaves and willing. Severely affected branches' tops dried up with the increasing time of continuing drought. After severe drought stress for 30 days, partial seedings of U. elongata and K. bipinnata died, whole leaves of P. chinensis turned yellow or red, and leaves in the middle and lower portions of L. formasana and Q. texana turned yellow and dry. The chlorophyll and relative water content in the leaves of the five tree species decreased; the relative conductance and malondialdehyde (MDA) concentration in leaves increased; the content of free proline, soluble sugar and protein in leaves increased. The SOD, POD, and CAT activities in the leaves of Q. texana increased, whereas it increased and then decreased in L. formosana, P. chinensis, and K. bipinnata trees. With the increasing drought extent, the SOD and CAT activities in the leaves of U. elongate increased at first and then decreased, while the activity of POD increased with the increasing drought stress. Membership function analysis showed that under moderate and severe drought stress, drought resistance levels were Q. texana > L. formosana > P. chinensis > U. elongate > K. bipinnata. Conclusion: Q. texana has the strongest drought resistance among the five tree species, which provides a competitive advantage for afforestation usage in difficult sites.