Table 2.— Qualitative comparison of experimentally induced abiotic stresses on various Pseudotsuga menziesii and Pinus ponderosa needle 

 tissues' 



Treatment 



External 

 symptomatology 



Mesophyll 



Transfusion 

 Endodermis parenchyma 



Xylem 

 parenchyma 



Phloem 



Phloem 

 parenchyma 



Epithelial 

 cells 



Staining patlem. 

 in vascular 

 tissue 



Control 



Needles re- 

 mained deep 

 green 



Fully turgid, 

 plastids not 

 clumped, 

 dispersed 



Intact, 

 turgid 



Turgid 



Turgid 



Turgid 



Turgid 



Turgid 



No deep stain- 

 ing, xylem light 

 pink, phloem 

 light green, stain 

 homogeneous 

 throughout 



Salt, 12,000 

 ppm in tap- 

 water 



Chlorosis of 

 base, middle, or 

 tip within 15-20 

 days, zone be- 

 tween necrotic 

 and green tissue 

 not distinct 



Extreme 

 plasmolysis, 

 chloroplasts 

 destroyed 



Inact, turgid Collapsed 



Collapsed 



Disintegr- 

 ated 



Collapsed 



Collapsed 



Normal, no par- 

 ticular concen- 

 tration of stain 



Drought, 



water 



withheld 



Chlorisis and 

 necrosis within 

 15-25 days, 

 often progress- 

 ing acropetally 

 from base. Dif- 

 fuse, no distinct 

 banding 

 Needles twist 



Collapsed, 

 but not 

 plasmolyzed 



Intact, 

 turgid 



Collapsed 



Collapsed 



Collapsed 



Collapsed 



Collapsed 



Normal, no par- 

 ticular concen- 

 tration of stain 



Winter dry- 

 ing, roots 

 frozen, 

 25-30°C, 

 slight 

 breeze 



Same as 

 drought, but in- 

 jury occurs 

 within 3-5 days 



Collapse 



Intact, 

 turgid 



Collapsed 



Collapsed 



Collapsed 



Collapsed 



Collapsed 



Same as Salt 

 and Drought 



Sulfur diox- 

 ide, 5 ppm 



Chlorosis at tips 

 or slightly prox- 

 imal to tip 

 within 3-8 h, 

 abrupt transition 

 between green 

 and chlorotic 

 tissue 



Clumping of 

 plastids, 

 some 

 collapse 



Collapsed 

 where 

 mesophyll 

 is necrotis 



Hypertrophy 

 and 



hyperplasia 



Hypertrophy 

 and 



hyperplasia 



Hyper- 

 trophy, 

 hyper- 

 plasia, & 

 collapse 



Hypertrophy 

 and 



hyperplasia 



Hyper- 



trophied, 



occluding 



resin 



canal 



Intense purple- 

 red and purple- 

 blue extending 

 basipetally into 

 area of non- 

 damaged 

 mesophyll 



Fluoride, 

 5 ppb 



Chlorosis slight- 

 ly below tips 

 within 5-6 h, 

 progressing 

 acropetally. 

 Abrupt transition 

 zone 



Clumping of 

 plastids, lit- 

 tle collapse 



Collapsed 

 where 

 mesophyll 

 is necrotic 



Hypertrophy 

 and hyper- 

 plasia 



Hypertrophy 

 and 



hyperplasia 



Hyper- 

 trophy 

 and hyper- 

 plasia 



Hypertrophy 

 and 



hyperplasia 



Hyper- 



trophied, 



resin 



canals 



occluded 



Same as SO 



H 2 S, 

 50 ppm 



Well defined tip 

 chlorosis within 

 20 h, necrosis 

 limited to tips, 

 transition zone 

 abrupt. 



Same as 

 SO , HF 



Same as 

 SO., HF 



Same as 

 SO and HF 



Same as SO 

 and HF 



Same as 

 SO and 

 HF' 



Same as S0 2 

 and HF 



Same as 

 SO and 



2 



HF 



Yellow tones in 

 cell walls, in- 

 tense purple-red 

 in lumens, ex- 

 tending 



basipetally into 

 area of non- 

 damaged 

 mesophyll 



CHS, 



2 6 



50 ppm 



Tip chlorosis 

 within 20-15 h, 

 transition zone 

 abrupt 



Same as 

 SO,, HF 



Same as 

 SO and HF 



Same as 

 SO and HF 



Same as S0 2 

 and HF 



Same as 

 S0 2 and 

 HF* 



Same as S0 2 

 and HF 



Same as 

 SO and 

 HF' 



Same as SO 

 and HF 



1 AII observations were made within the transition zone, a 2 mm segment including the necrotic, chlorotic, and gteen portions of injured needle. Generally, the transition 

 zone is chlorotic. 

 2 Feulgen's and fast green schedule. 



5 



