Above-canopy sprinkler irrigation with saline water favours the absorption of salts by wetted leaves and this can cause a yield reduction additional to that which occurs in salt-affected soils. Outdoor pot experiments with both sprinkler and drip irrigation systems were conducted to determine foliar
The use of chlorophyll fluorescence as a screening method for cold tolerance in maize
β Scribed by A. H. C. M. Schapendonk; O. Dolstra; O. Kooten
- Publisher
- Springer
- Year
- 1989
- Tongue
- English
- Weight
- 600 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0166-8595
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β¦ Synopsis
Chlorosis in maize (Zea mays L.) is a common phenomenon in the 12 to 17Β°C temperature range. A newly developed chlorophyll-fluorescence technique was used to elucidate the underlying subcellular processes of resistance to chlorosis. Four populations were used that were developed by divergent mass selection for contrasting resistance to chlorosis in a cold-tolerant dent and a cold-tolerant flint population. Young plants from the four populations were kept for six days at 17/10, 15/10 and 13/10Β°C (day/night). After 1, 3 and 6 days various chlorophyll-fluorescence parameters were determined. The measurements were done on leaf 4. Differences were not uniform for all fluorescence properties. The resistant and susceptible populations of the two sets differed for the Q-quenching which is related to the electron transport rate in the chloroplast. For the E-quenching which is related to the Calvin cycle activity, the resistant dent differed significantly from the other three populations. The ratio Fm/Fo (related to the transfer of absorbed light-energy from antennae pigments to reaction centers in the chloroplast) was higher for the resistant dent population than for the susceptible one. The flint types did not differ for this property.
Apparently, divergent mass selection for chlorosis resistance resulted in various changes at the subcellular level that are not necessarily comparable for flint and dent types.
When after 6 days the temperature was raised from 13Β°C to 17Β°C, the fluorescence signals led to the conclusion that there was a full recovery of various processes after two days, except for the metabolic activity of the susceptible flint.
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