Stomatal responses in rainfed lowland rice to partial soil drying; comparison of two lines

Previously; we demonstrated that root Ups in drying soil communicate with shoots for stomatal closure. hi rainfed Wand rice, despite further water being available at depth. This study examines variation between two lines in root. signals. Rice lines CT9993 and IR62266 were grown in the held, and in die greenhouse with the split-root root-sever wax-layer system, to investigate their responses to mild and severe water deficit by monitoring stomatal conductance leaf water potential and leaf ABA concentration, In We greenhouse root systems were divided, withholding water from one portion, and in some cases, severing the droughted portion of roots to remove be signal. Wax layers differing in strength were placed at hardpan depth. Roots of CT9993 were better able to penetrate the wax layers. IR62266 exhibited stronger than CT9993 with W62266's stomatal conductance dropping sharply under water deficit, and recovering at slower rates but less completely, when roots subjected to drying soil were severed. The greater stomatal response in IR62266 was associated with a higher leaf, ABA concentration during Car, inner deficit which in turn was associated with its greater number or roots in drying soil In the Held, a second reduction hi g was observed under severe water deficit, with stronger signals in IR62266 associated with more conservative water toe as soil drying intensified. To better exploit subsoil water in mild or transient water deficit, selection for reduced root signals might he warranted

Stomatal responses in rainfed lowland rice to partial soil drying; evidence for root signals

The role of root signals in water deficit responses of rice (Oryza saliva L.) is important in the alternate flooding and drying conditions encountered in the rainfed lowlands, where the abundant roots in shallow soil layers may generate signals when droughted, with consequent reduction in stomatal conductance (g(s)) and growth, despite the likelihood of additional water in deeper soil layers. This study was conducted to confirm the presence of root signals, explore their nature and plant responses, consider the suitability of the methods, and discuss implications for adaptation under rainfed lowland drought. A split-root technique was used in greenhouse studies, whereby roots were divided into two sections: flooded and droughted. The decrease in g(s) and transpiration rate (Tr) due to drying of a portion of the roots, and their apparent recovery upon severing of this root portion, were consistent with the role for signals. The field study confirmed the evidence for root signals during progressive soil drying, whereby g(s) and Tr decreased before leaf water potential (Psi(L)) started to decline. The increase in leaf ABA concentration under field drought, and its strong association with soil moisture tension and g(s), suggested its involvement in mediating stornatal responses during early drought in rice. The recovery in Psi(L) after severing of droughted roots in the greenhouse could be attributed to increased hydraulic conductance. These responses imply a role for both chemical and hydraulic signals in rice, which have important implications for adaptation and crop performance in contrasting rice ecosystems

Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

International audiencePreceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector is developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M$_{\odot}$ star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance