Water-Deficit Stress Induced Root Morphological and Anatomical Plasticity in Triticum Dicoccoides.

Wheat, one of the world’s major staple cereal is highly sensitive to harsh environmental conditions, particularly water-deficit stress. Eighteen wheat accessions (17 Triticum dicoccoides wheat accessions and one popular variety Everest) were exposed to two water regimes, (1) well-watered control (100% Field capacity (FC)) and (2) Water-deficit condition (40-45% FC) in 1.5 m lysimeters to investigate root morphological and anatomical plasticity. Water-deficit stress was imposed 18 days after transplanting during the vegetative stage and continued for 30 consecutive days of the stress. During the stress period, daily water loss was gravimetrically captured and physiological measurements including SPAD, light adapted quantum yield of PS-II, flavonoids were recorded on alternative days and thermal images captured at 4 days interval on all 18 accessions. The top most fully expanded leaf just before stress release, were collected for estimating Carbon Isotope Discrimination. The entire root was separated from the shoot and stored in 20% (v/v) alcohol and stored at 4°C for root scanning and image analysis, while sections of seminal root (from root shoot junction and 6 cm above the root tip) were collected and stored in 40% (v/v) alcohol for capturing root anatomical plasticity. Different root morphological attributes like total root length, root diameter, and average root thickness were computed by analyzing images in WinRHIZO software. Root anatomical traits such as stele diameter, late metaxylem diameter and number from both the collected root segments were recorded. These rooting responses studied in relation to water-deficit stress conditions from Triticum dicoccoides accessions will be utilized for genetic mapping for drought resilience and water–use-efficiency (WUE) traits from populations developed at KSU using these wild accessions. Novel findings and opportunities to improve rooting biology to enhance WUE in wheat will be discussed.