Boron Deficiency and Chilling Injury Interactions in Tobacco Transplants Grown in the Float System

Abstract

Boron deficiency and chilling injury produce similar symptoms in young tobacco transplants. Mistaken identification of chilling injury as B deficiency has resulted in B toxicity when growers apply additional B to non-deficient plants. In order to distinguish between B deficiency and chilling injury, it is important to determine an approximate B deficiency threshold and to determine the effects of suboptimal temperatures on growth and B uptake. In an experiment to determine tissue concentrations of B associated with B deficiency symptoms, transplants grown at a day/night temperature regime of 26/22ºC exhibited B deficiency symptoms at 10-20 µg B g-1 dry matter. These tissue levels resulted from solution concentrations of 0.19-1.9 µM B (0.002 to 0.205 mg L-1 B). Root and shoot growth of flue-cured cultivars was near maximum at a 26/26ºC day/night temperature regime. Burley cultivars were adapted to a wider temperature range for optimum growth compared to flue-cured cultivars. The B deficiency threshold decreased with decreasing temperatures and with increased day/night temperature differentials. Sub-optimal temperatures appeared to be the primary growth limiting factor for tobacco transplants in the float system with low B availability. Boron deficiency was a secondary factor in limiting growth.

Cold stress in the harvest period: effects on tobacco leaf quality and curing characteristics

“…Cold stress could reduce the agronomic traits such as plant height, leaf number and stem circumference of flue-cured tobacco, thus affecting the morphological formation of flue-cured tobacco. The quality of fresh tobacco leaves is an importantly influences to curing characteristics and tobacco yield and quality [ 6 ]. Cold stress can change the quality of fresh tobacco leaves by affecting the microstructures, chloroplast pigment content and maturity of tobacco leaves, further reduced the curing characteristics of tobacco leaves.…”

The Effects of the Field Cold Stress in the Harvest Period on the Quality and Curing Characteristics of Tobacco Leaves

“…The two aspects are rst found in agronomic traits and the quality of fresh tobacco leaves. The quality of fresh tobacco leaves is a key link that directly in uences the curing characteristics and the yield and quality of tobacco [9]. The quality of fresh tobacco leaves is directly re ected by microstructures, chloroplast pigment content and the maturity thereof.…”