Shigeki Konishi

Stimulatory effects of aluminum on the growth of cultured roots of tea

Abstract The effect of Al on the growth of excised tea (Camellia sinensis L.) roots differentiated from stem segments in vitro was investigated in shaking liquid culture. 1) The optimum initial pH for tea root growth in modified MS medium was 5.5. Growth of main and lateral roots was affected by the difference in NAA concentrations. Main root growth was stimulated by 5×10-7 and 1×10-6 M NAA, and lateral root growth was stimulated by 5 × 10-6 and 1 × 10-5 M NAA. 2) Main root growth showed a progressive increase for 3 weeks, then became stationary. Lateral roots began to grow at 2 weeks, with a progressive increase over the following 6 weeks. 3) The growth of the tea roots in the main or lateral root growth medium was stimulated by the supply of Al and P together, but was not affected when Al and P were supplied separately. 4) The pH of the culture medium decreased gradually to about 4.0 during the shaking culture, and remained stable. Growth of roots supplied with Al was stimulated after the decrease of me...

Effect of the Formation of a Sugar-Borate Complex on the Growth Inhibition of Pollen Tubes of Camellia sinensis and Cultured Cells of Nicotiana tabacum by Toxic Levels of Borate

Abstract The relationship between exogenously supplied sucrose, glucose, and fructose and growth inhibition of tea pollen tubes cultured in a liquid medium and of cultured tobacco cells by toxic levels of borate was investigated. In the medium containing 0.2 M sugar at pH 5.8, tea pollen tube growth was strongly inhibited by 20 mM borate with sucrose, and by 10 and 20 mM borate with glucose, but not inhibited even by 20 mM borate with fructose. The growth inhibition of the pollen tubes by 20 mM borate was obviously alleviated when the concentration of fructose exceeded 0.2 M and the pH of the medium exceeded 5.4. Twenty millimolar borate inhibited the growth of tobacco cells in the media with sucrose and glucose, but not with fructose at pH 5.8. The ability of sugars to form a borate complex was in the decreasing order of fructose, glucose, and sucrose based on the decrease of the pH of the mixtures of sugars and borate. It is, therefore, suggested that the toxicity of boron was reduced by the formation o...

Effect of aluminum on callose synthesis in root tips of tea (Camellia sinensis L.) plants

Abstract Aluminum (Al) toxicity is a major factor limiting yield production on acid soils (Foy 1983). The initial symptom of Al toxicity in many plants is manifested by the inhibition of root elongation (Ownby and Popham 1990; Llugany et al. 1994; Sasaki et al. 1994; Horst et al. 1997), which occurs during a very short period of time after exposure to Al (Llugany et al. 1994; Stas and Horst 1995). In a large number of recent reports, it was shown that the root apex plays a major role in the Al-sensitivity and response mechanisms (Zhang et al. 1994; Sasaki et al. 1997; Sivaguru and Horst 1998). However, it is interesting to note that stimulatory effects of Al on the growth of plants have also been reported in some studies (Chenery 1955; Konishi et al. 1985; Huang and Bachelard 1993; Osaki et al. 1997). In tea plant (Camellia sinensis L.) a stimulatory effect of Al on the growth was also demonstrated in some experiments, using intact plant (Chenery 1955; Konishi et al. 1985), cultured roots (Tsuji et al. 19...

Stimulatory effect of aluminum on the growth of tea pollen tubes

Abstract It is well known that when inorganic elements such as boron (B), calcium, cobalt, and manganese are added to media in combination or alone, they stimulate the germination and/or tube growth of various kinds of pollen (Schmucker 1933; Loo and Hwang 1944; Yamada 1958; Brewbaker and Kwack 1963). Among these elements, the stimulatory effect ofB is the most effective and generally recognized. Aluminum (Al) belongs along with B to Group IIIa in the periodic table, and Fahnrich and Ultlich (1964) reported that Al inhibited the germination and growth of the pollen tube of Petunia hybrida and Antirrhinum majus. However, stimulatory effects of Al on pollen germination or pollen tube growth had not been previously reported.

Uptake and loss of 45Ca2+, 22Na+, and H2 32PO4 -by tea pollen tubes

Abstract Uptake and loss of 45Ca2+, 22Na+, and H2 32PO4 - by tea pollen tubes precuitured for 20 h were studied to clarify the pattern of ion uptake by pollen tubes. Uptake of 45Ca2+, 22Na+, and H2 32PO4 - which increased with the incubation time became maximum after 5, 1, and 8 h for 45Ca2+, 22Na+, and H2 32PO4 -, respectively. After the maximum uptake, the ions were excreted. The 45Ca2+ uptake was highest at pH 7.5 and the 22Na+ uptake increased as the solution pH increased up to 7.8. The H2 32PO{8in4}- uptake was greatest at pH 5.5. The uptake of 45Ca2+ and H2 32PO4 - was maximum at 25°C. The uptake of H2 32PO4 - was more affected by the temperature than that of 45Ca2+. Metabolic inhibitors [2,4-dinitrophenol (DNP), ouabain, chloramphenicol, and cycloheximide] suppressed the uptake of 45Ca2+ and H2 32PO4 -, but had no effect on the uptake of 22Na+. The 22Na+ uptake was reduced by the addition of Ca2+ but not K+. The loss of 45Ca2+ from the pollen tubes which showed three successive phases, was prevente...

Effect of phosphorus on zinc toxicity in tea pollen tube growth

Abstract Although zinc (Zn) is an essential element for the growth of higher plants, excess supply may lead to growth inhibition. Symptoms of Zn toxicity are characterized by a reduction in root growth and leaf expansion followed by chlorosis (Mengel and Kirkby 1987), especially root elongation is severely inhibited (Godbold et al. 1983). Due to the increase of input of Zn to farmland by the application of sewage sludge or large amounts of Zn-containing pig manure, Zn toxicity may become an important problem in certain regions (Ruano et al. 1987). In addition, Zn toxicity is also a problem in some acidic soils (Takahashi et al. 1980). Increasing soil pH by liming is the most effective procedure for decreasing both Zn content and Zn toxicity in plants (White et al. 1979), because Zn solubility decreases 100 times for each unit increase in pH (Neue and Lantin 1994). As an alternative approach, application of large amounts of phosphorus (P) fertilizer was employed to detoxify Zn (Takahashi et al. 1980). Howe...

A new method for assessing pollen tube growth and its application to study alleviation of aluminium stress

We established a new method for assessing pollen tube growth by determination of callose content and examined the Al stress alleviation substances in vitro. Callose (s-1,3-glucan) deposition during pollen tube growth was closely related to growth but was not related to aluminium (Al) stress.

Factors limiting tea pollen tube growth in soil solution from three acid soils

Factors limiting pollen tube growth (PTG) of tea (Camellia sinensis L.) from three acid soils: red-yellow acid soil (RYS) (Acrisols), high-humic Andosol (HHA)(Andosols) and acid sulfate soil (ASS) (Thionic Fluvisols) solution were investigated. PTG was inhibited in the untreated low pH soil solution, but improved at pH 4.5 to 6.5. Addition of both Ca and В increased PTG. At pH 4.5, citric acid and humic acid alleviated the inhibition of PTG induced by RYS, but not that by HHA and ASS. These findings suggest that low pH and deficiency of Ca and В were the limiting factors in all soils, and Al toxicity was also a limiting factor in RYS.