Kunito Nehira

Effect of salinity on growth, photosynthesis and mineral composition in leguminous plant Alhagi pseudoalhagi (Bieb.)

Abstract Leguminous plant Alhagi pseudoalhagi was subjected to 0 (control), 50, 100, and 200 mM NaCI treatments during a 30 d period to examine the mechanism of tolerance to salinity. Plant dry weight, net CO2 assimilation rate, leaf stomatal conductance, intercellular CO2 concentration, and solute concentration in leaves, stems, and roots were determined. Total plant weight in the 50 mM treatment was 170% of that of the control after 10 d of treatment. Total plant weight was lower in the 100 and 200 mM treatments than in the control. The leaf CO2 assimilation rate was approximately 150% of that of the control in the 50 mM treatment, but was not affected significantly by 100 mM of NaCI, while it was reduced to about 60% of that the control in the 200 mM treatment. Similarly stomatal conductance was consistent with the CO2 assimilation rate regardless of the treatments. Intercellular CO2 concentration was lower in the NaCI-treated plants than in the control. Changes in CO2 assimilation rate due to salinity...

Effect of salinity on growth and accumulation of organic and inorganic solutes in the leguminous plants Alhagi pseudoalhagi and Vigna radiata

Abstract The response of two leguminous plants Alhagi pseudoalhagi and Vigna radiata to seawater salinity was studied over a period of 30 d. The growth of Vigna radiata was markedly and gradually reduced by increasing salinity levels, whereas that of Alhagi pseudoalhagi was promoted at 9.1 and 16.2 dS m-1 salinity but then was slightly reduced at 28.2 dS m-1 salinity. These results indicate that Alhagi pseudoalhagi belongs to the group of halophytic plants. Seawater salinity caused changes in the membrane permeability measured as electrolyte leakage in both plants. Alhagi pseudoalhagi maintained a lower membrane permeability than Vigna radiata. With increasing salinity levels, the membrane permeability decreased in Alhagi pseudoalhagi, whereas, in Vigna radiata it slightly increased at 9.1 dS m-1. The leaf water potential and the osmotic potential decreased in both plants along with the seawater salinity levels. However, the turgor potential and osmotic adjustment in Alhagi pseudoalhagi were maintained at...

Twenty-one years post-fire succession in a small watershed on Etajima Island, Hiroshima Prefecture, Southwestern Japan

This study was conducted in a small watershed in Etajima Island, southwestern Japan to ascertain species performance 21 years after the fire using the Braun-Blanquet’s method. Five plots were laid out in the burnt area for the interpretation of succession taking the edaphic or topographic conditions into consideration. Two fern species, Gleichenia japonica and Dicrapnopteris dichotoma, that grew from surviving subterranean organs a year after the fire helped much in the recovery of the vegetation. At the onset of succession, soil erosion was controlled and trees invasion prevented due to the rapid growth and distribution of these ferns. Vegetation growth showed variations as could be gleaned from the length of time when the shrub, sub tree and tree layers have pervaded the area. In 1996, the tree layer appeared in a NW-valley side slope (Plot 3) with Pinus densiflora enlarging its crown over other broad-leaved trees. Clethra barbinervis, on the other hand, started developing in the sub tree layer in the plot on valley bottom at lower slope (Plot 1), middle valley bottom slope (Plot 2), and NE-valley side slope (Plot 4) in 1980, 1989, and 1985, respectively. In 1990, Pinus densiflora developed in NW-valley side slope (Plot 3) and on the ridge plot (Plot 5). Shrub layer developed in all plots two years after the fire except the plot on the ridge (Plot 5) where shrub appeared after four years.

Anatomical studies on seeds and seedlings of some Utricularia (Lentibulariaceae)

The undifferentiated mature embryos of someUtricularia studied consist of large polygonal cells which contain many starch grains. Later, they consist mostly of large polygonal cells with some small cells in one or more regions adjacent to the seed coat, which lack starch grains but have rather easily visible nuclei. After these small cells divide and produce more cells of the same type toward the midcenter of the embryo, they form one or more primordia which grow into the primary structures of the seedling. The primordia of the embryo seem to have no pattern as to which primary vegetative structure they will develop into. However, the terrestrial species ofUtricularia studied showed some non-cotyledonous, primary differences in germination patterns; some form primary foliar units, some form stolons, and some form bladders. The first and second primary foliar units of aquaticUtricularia radiata andV. gibba subsp.gibba do not follow in the same manner as cotyledons. No cotyledon could be distinguished in any of theUtricularia seedlings studied. In the seedlings ofU. gibba subsp.gibba andU. radiata, appearance and differentiation of the vascular elements occur simultaneously in more than one direction, toward the meristematic tissues of primary vegetative structures and toward the midcenter of the embryos. Lloyd’s proposed term: “cotyledonoids” (1942) and that of Kumazawa: “cotyledons” (1967) should not be used for the first and second primary foliar units in either aquatic or terrestrial to terrestrial-epiphyticUtricularia, unless further supportive evidence is accumulated.