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A growth study of sugar beet treated with gibberellic acid and (2‐chloroethyl)trimethylammonium chloride (CCC)
Author(s) -
HUMPHRIES E. C.,
FRENCH S. A. W.
Publication year - 1965
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1965.tb07878.x
Subject(s) - petiole (insect anatomy) , gibberellic acid , dry matter , biology , sugar beet , dry weight , horticulture , sugar , gibberellin , agronomy , botany , zoology , germination , biochemistry , hymenoptera
SUMMARY Gibberellic acid sprayed on sugar‐beet plants decreased leaf production, whereas (2‐chloroethyl)trimethylammonium chloride (CCC) applied to the soil increased it. These changes were associated with a change in shape of the growing point; GA elongated it and CCC flattened it. Leaf area per plant increased to a maximum of about 28 dm. at the end of June; CCC consistently decreased it, but GA had no effect although the plant had fewer leaves than the controls. GA increased petiole length in the first part of the season but later diminished it. Petiole length increased with amount of GA applied. CCC had the opposite effect, decreasing petiole length at the beginning of the season and afterwards increasing it. Total dry matter of plants treated with GA was significantly increased at harvests 3 weeks and 8 weeks after initial application. CCC‐treated plants had less dry matter throughout. GA increased crown dry weight and the effect increased with the amount applied. Neither GA nor CCC significantly influenced the weight of storage root. Plants overwintered in an unheated glasshouse continued to increase in dry matter; GA increased the weight of flowering stems but CCC had no effect. From observations on individual leaves mean leaf area growth curves for successive groups of five leaves were constructed. Gibberellic acid increased both areas and longevity of leaves 8 to 17 and GA‐treated plants had the same dry weight as controls in spite of fewer leaves, because leaf area duration was increased. This study emphasizes that different leaves contribute very differently to the total dry matter of the plant. Each of leaves 8–17 had an average duration of 22 dm. 2 ‐weeks and together they produced about two‐thirds of the final dry matter in autumn. CCC decreased leaf area duration and dry matter. None of the treatments changed net assimilation rate (E). In previous experiments with mustard plants CCC decreased E, either through a direct inhibitory effect of CCC on photosynthesis or through decrease in photosynthesis because the dwarfed stem in the treated mustard provided only a small sink for photosynthates. In sugar beet CCC does not affect E, possibly because the root provides a large sink. The differences between sugar beet and potato in development of leaf area and production of dry matter are discussed and the importance of leaf area duration emphasized. GA affects sugar beet and potato differently. It hastens leaf senescence in potato but delays it in sugar beet. GA may prolong the life of sugar‐beet leaves because by making them fewer it decreases competition between them. Gibberellic acid causes a transient increase in leaf growth and dry‐matter production both in sugar beet and potato.