The influence of the physiologically active substances and of the natural bioregulators on tobacco seed, seedlings and plants
The goal of the research was to improve the germination of tobacco seeds in order to obtain a healthy, vigorous, uniform seedling, ready to be transplanted in the shortest time.
For the tobacco seed, cultivar Baragan 132, the following variants were used:
- Hydrochlorate procaine in concentration of 0.05%; 0.1% and 0.2%;
- Nicotinic acid in concentration of 0.05%; 0.1% and 0.3%;
- Indolic-acetic acid (IAA) in concentration of 0.01% and 0.05%;
- Naphtyl-acetic (NAA) in concentration of 0.01% and 0.05%;
- Thiourea in concentration of 0.1%; 0.2% and 0.3%;
- Control (water).
For the tobacco seedlings the tested variants were:
- Indolil-acetic acid (IAA), in concentration of 1%;
- Vitamin PP, in concentration of 1%;
- PEI - 412, in concentration of 1%;
- Naphtyl-acetic acid (NAN), in concentration of 1%;
- Thiourea, in concentration of 1%;
- Revital, in concentration of 1%;
- Control (not treated).
The tobacco seed was treated for 24 hours with these products, and afterwards left to germinate. The germinative energy and faculty of the seeds was determined according to valid standards. The use of the substances at low concentrations (0.01 - 0.05%) upon the tobacco seed improved the germinative energy by 7-14% and the germinative faculty by 9-11%, compared with the control. The hydro chlorate procaine and thiourea can be recommended as stimulus for the seed germination, in concentrations up to 0.2%. The other substances, nicotinic acid and IAA, can be used at low concentrations up to 0.05% but NAA showed no results in stimulating the tobacco seed. For the tobacco seedling, the substances were used at the beginning of the phase of "little ears". Before and after the treatments the height of the plantlets was measured and the number of leaves was determined. The most efficient variants at seedling stage were: Revital, PEI - 412 and thiourea, which acted as growth promoters of the plants, in height (2-4 cms more compared with the control), number of leaves (2-3 leaves more, compared with the control) and improved the uniformity and vigor of the seedlings. NAA was phytotoxic for the young plantlets. This phenomenon acted by stunting and curling the leaves. The seedlings obtained following these treatments were transplanted in vegetation pots and closely observed for yield. The yield of cured leaves ranged from 2,495 to 2,849 kgs/ha. The highest increase in yield was recorded for the variants treated with Revital (an increase of 354 kgs/ha, compared with the control).