Showing papers by "Kenji Omasa published in 2000"
TL;DR: It is concluded that high temperature given on the day of flowering decreased the ability of the pollen grains to swell resulting in poor thecae dehiscence, and that, besides this decrease,High temperature given just before the days of flowering lowered the function of the cae themselves to dehisce, causing poorer theCae deHiscence.
Abstract: To clarify the mechanism of high temperature-induced floret sterility in rice (Oryza sativa L.), we studied the effects of high temperature at flowering on the ability of thecae to dehisce and on p...
198 citations
TL;DR: The high sensitivity of small radicles of this species to salinity indicated that salt must be removed from the soil surface for seedling establishment.
151 citations
TL;DR: It was concluded that salinity adaptability in the later developmental stage of these species determines their distribution with respect to salinity.
Abstract: The effects of sodium chloride (NaCl), polyethylene glycol-6000, temperature and light on germination and the effects of NaCl on growth were investigated in two Chinese desert shrubs, Haloxylon ammodendron (C.A.Mey.) Bunge and H. persicum Bunge ex Boiss. et Buhse. Both species occur in non-saline sand dunes; H. ammodendron also occurs in saline land, although it is not dominant there. Percentage germination of H. ammodendron and H. persicum in -3.0 MPa (667 mmol kg -1 ) NaCl was 91 and 64%, respectively. Hydroponic culture of each species for c. 3 months with NaCl solutions of 0, 200, 400 and 600 mmol kg -1 showed that the survival of H. ammodendron was highest (82.3%) at 400 mmol kg -1 NaCl, while that of H. persicum decreased with increasing NaCl concentration and was low (11.1%) at 400 mmol kg -1 NaCl. Sodium concentration in shoot tissues of 99-day-old seedlings grown at 400 mmol kg -1 NaCl exceeded 1000 mmol kg -1 in both species, while Na concentration in non-transpiring young seedlings grown in 400 mmol kg -1 NaCl was 240 and 350 mmol kg -1 for H. ammodendron and H. persicum, respectively. The results indi- cate that both species have relatively low adaptability to salinity at the older seedling stage compared with that at the ger- mination and young seedling stage, and that H. ammodendron shows higher adaptability to salinity at the older seedling stage than H. persicum. It was concluded that salinity adaptability in the later developmental stage of these species determines their distribution with respect to salinity.
111 citations
TL;DR: The results strongly support the theory that the rapid swelling of pollen grains is a driving force for anther dehiscence and suggest that potassium ions function as a turgor regulator in the rapid swellings of pollen grain.
32 citations
TL;DR: In this article, the authors examined the foliar absorption of seven organic pollutants (acetone, acetonitrile, acrolein, methyl ethyl ketone (MEK), isobutyl methyl ketone, chloroform, and benzene), and ozone was examined.
Abstract: Foliar absorption of seven organic pollutants (acetone, acetonitrile, acrolein, methyl ethyl ketone (MEK), isobutyl methyl ketone (IBMK), chloroform, and benzene), and ozone was examined. Two woody species (Populus nigra and Camellia sasanqua ) were exposed to each pollutant at a concentration of 0.5 or 1.0 ppmv (Imol mol -1 ), and gas absorption and transpiration rates were measured simultaneously. Ozone and acrolein were effectively absorbed by both species. MEK was absorbed by C. sasanqua only. A model analysis of gas exchange rates revealed that foliar absorption of the three pollutants was predominantly through the stomata, and cuticular contribution on gas removal is, if any, very small. The plant leaves showed no detectable absorption of the other five organic pollutants. We conclude that plant leaves act as an effective sink for some organic pollutants but not for others. The factor that determines whether plant leaves can effectively absorb pollutants in this study seems to be whether the pollutant is effectively metabolized in the leaf cells.
31 citations
TL;DR: In this article, a 3D remote sensing of woody canopy heights using a new scanning helicopter-borne lidar system with high spatial resolution was examined, where almost ground surface was covered by scanning a laser beam of small footprints below tens of centimeters, and precise grid data were obtained by rectangular scan using a garbomirror scanner.
Abstract: In present paper 3-D remote sensing of woody canopy heights using a new scanning helicopter-borne lidar system with high spatial resolution was examined. This lidar system was characterized by (i) almost ground surface was covered by scanning a laser beam of small-footprints below tens of centimeters, (ii) precise grid data were obtained by rectangular scan using a garbomirror scanner, and (iii) there were two operational modes, first pulse mode (FP-mode) for measuring woody canopy and last pulse mode (LP-mode) for measuring ground level, of time interval meter measuring the elapsed time between the laser pulse emission and the return of the reflected pulse. FP-mode DEM (Digital Elevation Model, grid interval=33.3 cm) and LP-mode DEM were calculated from data measured by FP-mode and LP-mode. DSM (Digital Surface Model) was computed with an error of about 15 cm from the LP-mode DEM. Mesh data (DCHM) of woody canopy heights were obtained by subtracting the DSM from the FP-mode DEM. The laser-derived tree heights of 14 coniferous trees and 6 broadleaf trees estimated from the DCHM were in error by less than 47 cm (RMSE=19 cm) in comparison with the ground measured tree height. The median filter (3x3 mask) was effective for removal of spike noise in the DCHM. The result showed the accuracy of tree height estimate was extremely improved by the mentioned method using the scanning lidar system with high spatial resolution. keywords : 3-D remote sensing, DEM, DSM, scanning lidar system, tree height
31 citations
TL;DR: The behaviour of pollen grains during unfolding of the locule and the distribution of potassium in the locules in two-rowed barley suggested potassium ions moved from the inter-pollen space (locular fluid) into the pollen grains in a locule at the time of pollen-grain swelling.
21 citations
TL;DR: Pricking or pressing an ovary can induce anther dehiscence in cleistogamous two-rowed barley in the absence of lodicule swelling.
Abstract: Pricking or pressing an ovary can induce anther dehiscence in cleistogamous two-rowed barley in the absence of lodicule swelling. This response is considered to be inherited from a chasmogamous ancestor in which anther dehiscence is induced by the stimulus given to the pistil by the lodicule swelling, which causes floret opening.
14 citations