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Wplyw stosunkow wodnych na urodzajnosc czarnych ziem

100%

Licznar M., Drozd J.

Roczniki Gleboznawcze

|

1996

|

tom 47

|

nr 3-4

9-22

2

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Indukcja systemu obronnego u pszenicy i pszenzyta w warunkach stresu tlenowego

51%

Bennicelli R. P.

Acta Agrophysica

|

2002

|

tom 75

1-80

3

Wplyw zlokalizowanego stresu tlenowego w glebie na rozwoj korzeni i czesci nadziemnych kukurydzy [ modelowe badania rizotronowe ]

51%

Bennicelli R. P.

Acta Agrophysica

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1994

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tom 03

72

The aim of the study was to test the usefulness of split rhizotrone technique to investigate the effect of localized soil anoxia on root and shoot developement, using maize as a test plant. The experiment was performed in 6 split rhizotrons enabling differentiation of soil aeration status in each half of the rhizotron by blowing nitrogen or air through them. The rhizotrone consists of two parts (each 16.6 dm3 in volume) inclined with an angle 60°. Each part is constructed of 1 mm thick stainless steel plate with a glass inner wall for root observation and has dimensions 84 cm x 40.5 cm x 5.0 cm. The rhizotrons were filled in with a brown loess soil material (Eutric Camhisol) from Ap horizon (from Eli/6wka, near Lublin). Maize seedlings with the roots splitted between the rhizotrone halves (eukivars KLG 2210 and DEA) were used in the experiments. Until the stress period the soil moisture tension of 20-80 kPa provided good water and air conditions. At a stage of 8 leaves three treatments were applied for a period of 7 days; an oxic control (P/P), a localized anoxia with 50% of the roots in nitrogen treated part (P/A), and a complete anoxia (A/A) with gas nitrogen in both parts. During the stress period diurnal elongation rates of primary roots (by marking positions of the tips each day) as well as distribution of two indicators of soil oxygenation status with depth viz. of oxygen diffusion rate (ODR) and of redox potential (Eh) in soil were measured. Shoot elongation rates were monitored with a potentiometer attached to the youngest leaf. Microscopic photographs of cross- sections of the caps and of apical meristems of primary roots at 400 magnification were made to show the changes in their anatomy due to anoxia. Chemical analysis of the shoots was performed after the stress period. For each cultivar the experiment was repeated three times. The investigations performed allowed the following conclusions to be drown out: 1. The split rhizotrone was shown to be a useful technique to study behaviour of the primary maize roots under localized anoxia conditions. 2. The ODR and Eh distribution with depth showed deterioration of oxygenation status (drop of ODR from control values above 100 |µg m-2 s-1 to the level 30 µg m-2 s-1, decrease of Eh from control values above 550 mV to the level, 300 mV) due to replacement of the soil air with gaseous nitrogen. 3. Root elongation rates under anoxic conditions (both under complete - A/A, and localized - A/P anoxia) were on the level of about 50% of the controle (P/P) during first 4 days and decreased practically to zero by the end of the stress period. In turn, the oxic part of the rhizotrone combined with localized anoxia treatment of the same plant (P/A) exhibited compensation effect and was characterized by stimulation of the root elongation rate up to 80%. This effect was especially distinct after 2-5 days of the stress duration and then tended to decrease. 4Distribution of the root mass in depth under anoxic treatments was characterized by concentration of about 80% of the root mass within first 10 cm of the soil. 5.Microscopic photographs of the root tips showed, under anoxic conditions, shorter meristematic zone, smaller number of mitosis, beginning of aerenchyma formation and dying of the cells at a distance of 1 mm from the root cap. 6.The shoots responded to applying anoxia to both rhizotrone parts by 20% reduction of the growth rate. 7.Both root and shoot elongation rates were correlated also with the temperature. 8.Oxygen deficiency in soil resulted in an increase of exchangeable manganese, what was reflected by its increased concentration in the maize shoots.

Ograniczanie wyników

2 Acta Agrophysica

1 Roczniki Gleboznawcze

2 Bennicelli R. P.

1 Drozd J.

1 Licznar M.

1 2002

1 1996

1 1994

Wplyw stosunkow wodnych na urodzajnosc czarnych ziem

Indukcja systemu obronnego u pszenicy i pszenzyta w warunkach stresu tlenowego

Wplyw zlokalizowanego stresu tlenowego w glebie na rozwoj korzeni i czesci nadziemnych kukurydzy [ modelowe badania rizotronowe ]