Effect of Soil Moisture Stress at Panicle Initiation and Flowering Stages on Early Morning Leaf Temperature in Rice

Djanaguiraman M,Sachin S,Maragatham N,Thavaprakaash N

doi:10.29321/maj.2020.000386

Abstract

Field investigation on the influence of soil moisture stress (MS) on leaftemperature of rice at 0600 hours was made in Tamil Nadu AgriculturalUniversity, Coimbatore during Kuruvai (July-November) 2019 and Navarai(December-March) 2019-20 seasons. The treatments are T1: MS for 10days from PI, T2: MS for 15 days from PI, T3: MS for 20 days from PI, T4: MSfor 25 days from PI, T5: MS for 10 days from flowering, T6: MS for 15 daysfrom flowering, T7: MS for 20 days from flowering, T8: MS for 25 days fromflowering and T9: Control (Maintaining 2cm of water throughout the cropperiod). The experiment was laid-out in Randomized Completely Block Designwith three replications. Leaf temperature was measured using an infraredthermometer at 0600 hours. Moisture stress had a significant influence onthe leaf temperature of rice in the early morning hours. In Kuruvai season,an increase in leaf temperature was to the tune of 0.13oC to 2.20oC duringPanicle Initiation (PI) stage (T1, T2, T3 and T4) and 0.16oC to 2.27oC duringflowering stage (T5, T6, T7 and T8) over control due to MS. Similarly, increasedleaf temperature to the tune of (0.13oC to 2.97oC and 0.07oC to 2.96oCduring PI stage and flowering stage, respectively) was observed due to MStreatments than MS relieved treatments and control during Navarai season.The results confirmed that the direct influence on leaf temperature of rice wasdue to MS irrespective of the stages and seasons. The correlation betweengrain yield and leaf temperature due to the MS was found to be negative.

Highlights

Rice is the largest and the most intensively grown food crop, supplying more than 60 per cent of the world’s population with nutritious food
Moisture stress hinders the physiological activities of the plant and transpiration rate resulting in a reduction of total drymatter production
Yan et al (2012) reported that temperature of panicle and leaves were much higher under extreme water stress; reduced photosynthetic rate, transpiration rate and stomatal conductance

Summary

INTRODUCTION

Rice is the largest and the most intensively grown food crop, supplying more than 60 per cent of the world’s population with nutritious food. Rice consumes about 1200mm of water to complete its life cycle under irrigated condition. Moisture stress hinders the physiological activities of the plant and transpiration rate resulting in a reduction of total drymatter production. Leaf temperature could be used as an important physiological indicator for determining the opening or closure of stomata due to the response of crop under soil water stress (Jones et al, 2009). Though there are confirmed studies on leaf temperature due to moisture stress, there are limited reports on the influence of moisture stress period in two most critical stages of rice for irrigation (panicle initiation and flowering) on leaf temperature in tropical condition. The present study was made in two different seasons, viz., rainy (Kuruvai) and non-rainy (Navarai) to assess the impact of leaf temperature of rice in early morning hours due to the moisture stress

MATERIAL AND METHODS

RESULTS AND DISCUSSION

CONCLUSION