DNA from three families of rice plants selected in Northern China (each comprising the male sterile, the restorer, the hybrid F1 and the maintainer lines) has been extracted and amplified by PCR with different random DNA primers (RAPD analysis). Then, DNA has been analysed by agarose gel electrophoresis and DNA bands scored as present or absent. The generated matrices are reproducible and amenable for identification of each single plant line. Thus, RAPD fingerprinting of the inbred parental lines and of the resulting hybrid is proposed as a convenient tool for the identification, protection and parentage determination of plant hybrids. Furthermore, by offering a molecular tool to verify the degree of dissimilarity between the parental lines, the RAPD analysis may also be used to search for new parental combinations.

Protons having energies up to 3.8 MeV are experimentally generated by the p-polarized, 45 fs, ∼ 10 19 W/cm 2 laser pulse interacting with a near-critical plasma cloud produced by the irradiation of the amplified spontaneous emission (ASE) pedestal at an intensity of ∼ 10 13 W/cm 2 onto a 7.5-µm-thick polyimide foil target. The emission angle of the high-energy protons is shifted away from the target normal toward the laser-propagation direction of 45 • . The mechanism which explains the proton generation from the near-critical plasma cloud is discussed using the twodimensional (2D) particle-in-cell (PIC) simulation.

We present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. Sodium (Na) lidar and ionospheric observations by two digital ionospheric sounders are used to study the variation in the neutral metal atoms and metallic ions above thunderstorms. An enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na number density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry are considered in a Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation obtained by using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling.

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We report 19 coobserved enhanced sodium layers, including sporadic sodium layers (SSLs) and thermospheric enhanced sodium layers (TeSLs), over Hefei (31.8°N, 117.3°E) and Wuhan (30.5°N, 114.4°E) from 2011 to 2018. The total coobservation time at Hefei and Wuhan was 387.24 hr, and the average occurrence rates were 0.038 hr−1 and 0.028 hr−1 for the SSLs and TeSLs, respectively. The SSL and TeSL occurrence rates in summer were 0.078 and 0.039 hr−1, respectively, which were considerably higher than those in other seasons. Among all 19 cases, 16 cases, including 9 SSL cases and 7 TeSL cases, occurred almost simultaneously over Hefei and Wuhan without a time delay. Seven TeSLs and four out of the nine SSLs were accompanied by ionospheric sporadic E (Es), suggesting that an “Es‐SSL (TeSL)” chain formed via the wave‐induced wind shear mechanism. Three SSLs were modulated by waves and the two other cases were related with gravity wave overturning. In general, the correlation coefficients between Hefei and Wuhan for long‐duration cases (more than 2 hr) were high due to some large‐scale mechanism, and the short‐duration cases (less than 2 hr) had poor correlation due to different local characteristics. In addition, three cases were observed with an apparent time delay over Hefei and Wuhan, which might indicate the possible existence of long‐distance transport processes.