Root penetration of strong soil in rainfed lowland rice: comparison of laboratory screens with field performance

Stomatal Responses in Rainfed Lowland Rice to Partial Soil Drying; Comparison of Two Lines

“…While Yu et al (1995) identified lines that were divergent in their capacity to penetrate the wax barrier in aerobic soils, Clark et al (2002) successfully correlated laboratory findings with data obtained from fi eld experiments (Samson et al, 2002). The importance of roots capable of penetrating a hardpan in the rainfed lowlands was examined by Samson et al (2002) in a drought-prone environment where the clayey subsoils were heavily compacted.…”

“…Pronounced hardpans are usually present immediately beneath the plow layer and they can decrease root growth below them by as much as 60-80% (Kundu et al, 1996). In studying hardpans in pot experiments, Clark et al (2002) considered wax layers to be analogous to hardpans because they allowed mechanical impedance to be varied independently of water status and aeration. Thus, the use of the split-root systems setup (Fig.…”

Matching the Expression of Root Plasticity with Soil Moisture Availability Maximizes Production of Rice Plants Grown in an Experimental Sloping Bed having Soil Moisture Gradients

“…Plasticity in root branching in a shallow soil layer and rooting in the deep soil layer KDML105 has widely been cultivated in rainfed lowland rice areas of Northeastern Thailand (Jongdee et al, 2006;Kanjoo et al, 2012). The rainfed lowlands are characterized by the presence of a hardpan, which impedes deep root development, and the soil moisture fluctuations between aerobic and anaerobic conditions in the upper soil layer above the hardpan, and therefore, root distributions are commonly shallow and most of available water tends to be limited to the shallow soil layer (Clark et al, 2002;Samson et al, 2002;Kato et al, 2013). The root plasticity in terms of greater root branching ability in the upper soil layer has an important role in the efficient capture of water in recovering process after rewatering and relieved from the drought period (Kondo et al, 2003;Kano-Nakata et al, 2013).…”

Root Development, Water Uptake, and Shoot Dry Matter Production under Water Deficit Conditions in Two CSSLs of Rice: Functional Roles of Root Plasticity

“…For drought resistance, the consensus in 30 years of literature is that deep and thick roots are benefi cial to drought avoidance, especially in upland conditions, where soil moisture is available mainly in a deeper soil layer (Yoshida and Hasegawa, 1982;Lilley and Fukai, 1994;Nguyen et al, 1997;Price et al 2002;Kato et al, 2006Kato et al, , 2007Uga et al, 2011). However, in rainfed lowlands that occupy about one third of the global rice area and are mostly prone to drought (Wade et al, 1999;MacLean et al, 2002), these traits may not be exhibited because strong soil in the form of a hardpan can impede deep rooting (Clark et al, 2002;Samson et al, 2002). In addition, the effect of drought varies with the plant variety, degree and duration of stress and the growth stage of the plant Fukai, 1996a, 1996b), and the root traits responsible for the rice plant adaptation vary with the environment.…”