The possibility of supplying nutrients daily to tomato plants (Lycopersicum esculentum Mill.) grown in various seasons raised the question of the best percentage NO₃⁻/ NH₄⁺ to be supplied to these plants. The effect of four (8, 16, 24, and 34 C) temperatures and four percentage NO₃⁻/NH₄₊ (100/0, 75/25, 50/50, and 0/100) on the nutrient composition of tomato plants were studied. To obtain constant pH, percentage NO₃⁻/NH₄₊ and temperature continuous flow technique was used. The solution was flushed through the pots at a rate of 1 liter/hour. Increasing root temperature increased total-N, P, Mg, and K in the shoot irrespective of percentage NO₃⁻/ NH₄⁺ in the solution. Calcium concentration increased in the shoot with increasing temperature only when the plants were fed with NO₃⁻ as the only source of N. The presence of NH₄⁺> in the nutrient solution caused a decrease in Ca concentration in tomato plants grown in temperatures 16 C and above. Increase in the root temperature increased total-N and Ca, slightly increased P, and decreased Mg and K. Increasing root temperature increased N-N0₃⁻ concentration in the shoot, while decreasing it in thc roots. Low root temperature caused accumulation of N-NO³₋ and K in the roots. It is suggested that the hindering of translocation of these ions at low temperature is one of the factors that slows down growth of tomato plants fed with nutrient solution containing a high ratio of NO₃⁻.

Rehabilitation study of used soil mixes for further nursery work using improved Zuarungu variety of tomato is reported. Four treatments, unsterilized used, sterilized used, sterilized used plus nutrients, and sterilized unused mixes were evaluated for seed sowing, pricking-out, and potting. Steam sterilization for 4 h at 100 deg C of unsterilized used mixes caused increase in the N, P and K contents. Although many environmental factors, including nutrient and water supply affecting yield are of major importance, no single factor but a conglomeration of factors lead to good or poor growth, flower number, and other agronomic characters of tomato

A severe disease of Tomato cv. Molese, grown in Apulia, characterized by pronounced stunting of affected plants which also show malformed leaves and are unfruitful, is reported. The causal agent of the disease is a filamentous virus a normal length of 752 nm (Polyvirus group). Cytoplasmic inclusions, appearing as pinwheels or bundles, were abundantly found in ultrathin sections of artificially infected cells of Tomato. In immune electro microscopy tests, virus particles were heavily decorated when treated with two different antisera to Potato virus Y (PVY). The field syndrome was partially reproduced on Tomato cv. San Marzano and Molese by mechanical inoculation with infected crude sap. The low incidence of the disease in the field limits its economic importance although in favourable years the disorder may still represent a threat. | Si segnala la presenza in Puglia di una malattia di origine virale del Pomodoro cv. Molese caratterizzara da riduzione dello sviluppo e improduttivita delle piante che presentano, inoltre, foglie visibilmente malformate. La malattia e causata da un virus a particelle allungate e flessuose con lunghezza normale di 752 nm. In sezioni ultrasottili di cellule di piante di Pomodoro artificialmente infette sono stati osservati nel citoplasma inclusi girandola e particelle virali distribuite a caso o in aggregati monostratificati. In prove di immuno microscopia elettronica la particelle virali sono risultate decorate dagli anticorpi di due differenti sieri immuni al cirus Y della patata (PVY). La sindrome di campo e stata parzialmente riprodotta in serra inoculando con succo infetto giovani piante di Pomodoro cv. San Marzano e Molese. La bassa incidenza di questa malattia in campo limita a sua importanza economica sebbene in annate favore essa possa assumere aspetti molto piu preoccupanti.