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Tea plantations are widely distributed and continuously expanding across subtropical China in recent years. However, carbon flux exchanges from tea plantation ecosystems are poorly understood at the ecosystem level. In this study, we use the eddy covariance technique to quantify the magnitude and temporal variations of the net ecosystem exchange (NEE) in tea plantation in Southeast China over four years (2014–2017). The result showed that the tea plantation was a net carbon sink, with an annual NEE that ranged from −182.40 to −301.51 g C/m2, which was a much lower carbon sequestration potential than other ecosystems in subtropical China. Photosynthetic photon flux density (PPFD) explained the highest proportion of the variation in NEE and gross primary productivity (GPP) (for NEE: F = 389.89, p < .01; for GPP: F = 1,018.04, p < .01), and air temperature (Ta) explained the highest proportion of the variation in ecosystem respiration (RE) (F = 13,141.81, p < .01). The strong pruning activity in April not only reduced the carbon absorption capacity but also provided many plant residues for respiration, which switched the tea plantation to a carbon source from April to June. Suppression of NEE at higher air temperatures was due to the decrease in GPP more than the decrease in RE, which indicated that future global warming may transform this subtropical tea plantation from a carbon sink to carbon source. [ABSTRACT FROM AUTHOR]

Gravitational waves (GWs) from extra dimensions, very early universe, and some high-energy astrophysical processes might have at most six polarization states: tensor- and nontensor-mode gravitons. The peak regions or partial peak regions (of the amplitudes or energy densities) of some of such GWs are just distributed in the GHz or higher frequency band, which would be an optimal frequency band for the electromagnetic (EM) response to such high-frequency GWs (HFGWs). In this paper we investigate the EM response to the HFGWs, and for the first time we obtain the concrete form of analytic solutions of the perturbative EM fields caused by all six possible polarizations of the HFGWs in the background stable EM fields and in the proposed three dimensional synchro-resonance system (3DSR system), respectively. It is found that all such six polarizations may in principle show separability and detectability. Moreover, the detection frequency band ( ∼ 10 8 to 10 12 Hz or higher) of the signal photon fluxes by the 3DSR system and the observation frequency range ( ∼ 7 × 10 7 to 3 × 10 9 Hz) of the signals by the FAST (Five-hundred-meter Aperture Spherical Telescope, China) have a certain overlapping property, and thus their coincidence experiments in the future for observations will have high complementarity. [ABSTRACT FROM AUTHOR]

Identification of traits strongly associated with high yield can help future gene engineering towards improvements of productivity. Here we systematically determine the major architectural and physiological features associated with high yield in two elite historical hybrid rice cultivars, i.e., YLY1 and LYP9. Data from a six-year experiment show that high yield of YLY1 are related to a number of architectural and physiological parameters. Compared to LYP9, YLY1 had 5.5% and 47.3% higher canopy photosynthesis under high and low photosynthetic photon flux densities, respectively, during the grain filling stage, an average 1.5% higher proportion of biomass allocation to above-ground tissues, a 4.5%–10.5% higher photosynthate reserve in leaf sheath before grain filling, and a more efficient photosynthate translocation during grain filling and finally an average 25.2% higher number of productive tillers. These features differ dramatically from features associated with high yield in YLY900 and Yongyou12#, two other high-yielding rice cultivars in China. These identified features and their combinations can support designing new strategies in the future high-yield rice breeding. [ABSTRACT FROM AUTHOR]