Premium
Root zone calcium modulates the response of potato plants to heat stress
Author(s) -
Kleinhenz Matthew D.,
Palta Jiwan P.
Publication year - 2002
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2002.1150113.x
Subject(s) - calcium , meristem , heat stress , horticulture , stress (linguistics) , shoot , chemistry , botany , biology , zoology , linguistics , philosophy , organic chemistry
Potato plant growth and development are known to be severely impacted by heat stress. Here plants grown in a chemically inert medium of 1 : 1 quartzite : perlite (v : v) were subjected to either 35/25°C (stress) or 20/15°C (control) day/night air temperatures and four concentrations of root zone calcium (5, 25, 125 and 600 µ M Ca) for 3 weeks. We report for the first time that potato plant growth under heat stress can persist at specific levels of Ca 2+ in the root zone and that the Ca 2+ level required for growth under heat stress exceeds that required for growth under normal temperatures. We also provide strong, initial evidence that the ability of high Ca 2+ levels to mitigate heat stress effects results from shifts in meristematic activity. Total foliar mass and leaf area were essentially unaffected by Ca 2+ level under control temperatures. Under heat stress, leaf area was reduced to about 5% of the control at 5 and 25 µ M Ca but to only 70% of the control at 125 and 600 µ M Ca. Likewise, total foliar mass was reduced under heat stress to about 30% of the control at 5 and 25 µ M Ca but total foliar mass was greater under heat stress than control conditions at 125 and 600 µ M Ca. This increase at higher Ca 2+ concentrations was due primarily to axillary shoot growth. Anatomical studies of leaves grown under heat stress show that cell expansion was impaired by heat stress and this impairment was overcome by increasing root zone calcium levels. These results provide insight into the mechanism by which root zone Ca 2+ may modulate plant response to heat stress.