ISSN:
1573-5036
Keywords:
Ash alkalinity
;
Calcium
;
Cation distribution
;
Humidity
;
Magnesium
;
Mineral composition
;
Oxalate
;
Pectate
;
Tomato
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Tomato plants grown in water culture under two different humidity regimes (50% R.H. and 95% R.H.) were harvested at intervals over the growth period and cation uptake and calcium distribution investigated. The following results were obtained: 1. Plants in the high humidity regime initially grew faster but at the final harvest after 22 days, dry matter yields were the same. 2. In the high humidity treatment particularly towards the end of the experiment, the growth of the young leaves was disturbed and the plants showed symptoms resembling Ca or B deficiency. Analysis revealed that these tissues were lower in Ca than comparative tissues of the low humidity plants. The converse was true for B. 3. Cation uptake was little affected by the humidity treatment. However, the distribution of calcium within the plant was markedly influenced by humidity. In the high humidity treatment the level of Ca in the young leaves was very low and Ca accumulated in the stems. A high proportion of both Ca and Mg in these younger Ca deficient leaves was found to be associated with pectate. The same trend was observed in the stems, more of the Ca and Mg in this case being bound to oxalate as well as pectate. These results further indicate the possible significance of exchange movement of Ca particularly under low transpiration conditions when Ca transport by mass flow is restricted. 4. Xylem sap analysis showed a close cation-anion balance in all samples. NO3-ion was the predominant anion and the two major cations were K and Ca. This provides further evidence that the upper plant parts provide the major site of NO3-reduction in the tomato plant.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02185585
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