Assessment of drought tolerance capacity of tuberose (Polianthes tuberosa L.) on the basis of various growth and physio–chemical indicators
Sultan Ali1*, Rashad Mukhtar Balal1, Muhammad Mansoor Javaid2
1Department of Horticulture, College of Agriculture, University of Sargodha, Pakistan
2Department of Agronomy, College of Agriculture, University of Sargodha, Pakistan
Abstract
Bulbous crops like tuberose (Polianthes tuberosa L.) needs abundant amount of water for its better growth and development as compared to other floricultural crops. A mismanagement of irrigation may lead to severe damages to the crop and huge economic loss. Thus, to understand basis of irrigation needs and its impact on tuberose plant, a pot experiment was performed. Drought tolerance capacity of tuberose was assessed by analyzing morphological, physiological, enzymatic and bio-chemical attributes of two tuberose cultivars (Mexican Single and Pearl Double) under different irrigation regimes. Plants were grown in the plastic pots arranged in completely randomized design (CRD). Seven irrigation intervals (2, 3, 4,5,6,7 and 8 days; viz. T2-T7 respectively; T1 = control) were applied. Pots were placed in growth chamber with 30/25°C day/night temperatures and 50±5 % relative humidity. Results revealed that growth parameters in tuberose plant in both cultivars showed better performance under minimum irrigation interval (2 days) followed by 3 days and 5 days interval. Drought caused significant decreases in height of flowering stem (HFS; T2: 20 cm; T8: 10 cm), leaf area (LA; T2: 53.3cm2; T8: 16.9cm2), plant height (PH; T2: 27.6; T8: 12.74), fresh weight of flowering stem (FWFS;T2: 37.5;T8: 12.6), relative water content (RWC), photosynthesis rate (A), transpiration rate (E), stomatal conductance (SC) and chlorophyll contents (Chl) and increases in leaf water potential (LWP), water use efficiency (WUE), antioxidant enzyme activities (CAT, POD, SOD) and biochemical traits (Pro and Gly). However, enzymes activities like CAT, POD, and SOD; proline and glycinebetaine in the leaves of cultivar ‘Pearl Double’ were observed significantly higher than those in the leaves of ‘Mexican Single’ cultivar, regardless of irrigation intervals (water treatments). The results indicated that the growth performance of ‘Mexican Single’ cultivar was better than the ‘Pearl Double’ cultivar in drought conditions.
Keywords: Drought, Tuberose, Relative water content, Antioxidants, Photosynthesis
