M. Kitao et al., Manganese toxicity as indicated by visible foliar symptoms of Japanese white birch (Betula platyphylla var. japonica), ENVIR POLLU, 111(1), 2001, pp. 89-94
For the purpose of a field diagnosis of Mn toxicity, we showed the possibil
ity of using visible foliar symptoms of Japanese white birch (Betula platyp
hylla var. japonica Hara) as indicator. To examine the relationship between
the expression of visible symptoms and leaf Mn concentrations, white birch
seedlings were grown under four different Mn levels: 1 mg Mn l(-1) as cont
rol, 10, 50 and 100 mg Mn l(-1). Foliar symptoms of Mn toxicity for white b
irch were: (1) chlorosis at entire young leaves in the 50 and 100 mg Mn l(-
1) treatments; and (2) brown speckles at the leaf marginal and interveinal
area for old leaves in the treatments greater than 1 mg Mn l(-1). Mn prefer
ably accumulated into the leaf marginal and interveinal area, where the bro
wn speckles were observed. The mechanism determining the expression of symp
toms seems to be associated with the physiological state related to leaf ag
e as well as Mn distribution and concentration within a leaf. (C) 2000 Else
vier Science Ltd. All rights reserved.