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The effects of Arceuthobium sichuanense infection on needles and current‐year shoots of mature and young Qinghai spruce ( Picea crassifolia ) trees
Author(s) -
Xia B.,
Tian C.M.,
Luo Y.Q.,
Liu L.Y.,
Cairang D.Z.,
Ma J.H.,
Han F.Z.
Publication year - 2012
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/j.1439-0329.2011.00760.x
Subject(s) - biology , shoot , host (biology) , horticulture , botany , ecology
Summary Arceuthobium sichuanense is a hemiparasitic angiosperm that infects Qinghai spruce ( Picea crassifolia Kom.) in Qinghai province, China, and causes severe damage to spruce forests in Qinghai‐Tibet Plateau. In this study, the impact of A. sichuanense infection on mature and young trees of Qinghai spruce was evaluated by examining needle and current‐year shoot morphology, needle water and nitrogen‐use efficiency (NUE) and needle nitrogen concentration. The most apparent effect of A. sichuanense infection was a significant reduction in both needle size distal to infection and current‐year shoot length in the infected branches (p < 0.001). Per cent reductions in needle and current‐year shoot length were similar between mature and young trees (58.9 vs. 56.3%; 59.7 vs. 62.9%). There was a high degree of correlation in foliar δ 15 N values between the dwarf mistletoe and its host trees ( R 2 = 0.9017, p < 0.001), while the foliar δ 13 C values of A. sichuanense were similar to those of infected mature and young spruce trees. The dwarf mistletoe infection also resulted in a significant decrease in host needle N concentration and δ 13 C values (p < 0.001). The per cent reduction in needle N concentration in young trees was nearly twice as much as that in mature trees (20.49 vs. 11.54%), while the per cent reduction in needle δ 13 C values was similar between young and mature trees (−0.98 vs. −1.1‰). The NUE in mature trees was not affected by A. sichuanense infection, but the NUE in young trees was increased by the infection.