Authors: C W Wu M C Lee Y L Peng T Y Chou K H Lin Y S Chang
Publish Date: 2015/08/30
Volume: 54, Issue: 2, Pages: 193-200
Abstract
The objective of this study was to use nondestructive measurements as the precise irrigation indices for potted star cluster Pentas lanceolata Drought stress was imposed on plants for 0 3 5 7 12 and 16 d by withholding water Measurements were conducted on the third leaf counted from the apex upper leaves and on the third leaf from the bottom lower leaves Within the range of soil water content SWC from 10 to 45 leaf water potential WP SWC and soil matric potential SMP chlorophyll fluorescence photochemical reflectance index PRI adjusted normalized difference vegetation index aNDVI and the reflectance R at 1950 nm R1950 were measured The plants reached the temporary wilting point at −387 MPa of leaf WP the maximal fluorescence yield of the lightadapted state Fm′ ratio of uppertolower leaves was 17 When the Fm′ ratio was 13 it corresponded to lowerleaf WP −227 MPa SWC 21 SMP −20 kPa PRI 00443 aNDVI 00301 and R1950 8904 it was the time to irrigate In conclusion the Fm′ ratio of uppertolower leaves was shown to be a nondestructive predictor of leaf WP and can be used to estimate irrigation timing
Keywords: