The role of phosphorus, potassium and calcium on in vitro culture of lily bulblet

Lily is known as the third main bulbous flower in the world that used for cut flowers and pots. Bulblet as a staple procedure is known for propagation of this plant. Due to the high performance of in vitro bulblets regeneration, the use of this method can reduce the costs production of this plant and also reduction of water and soil pollution due to minimizing the field area for ex vitro propagation. The size of lily bulblets produced in vitro is smaller than ex vitro propagated bulblets. For this purpose, several concentrations of phosphorus, potassium and calcium were used to investigate their role on lily bulblet growth under in vitro condition.
 
In this experiment, ‘Santander’ cultivar was used for bulblet growth of lily. For this purpose, the effect of five strength (0, 0.5, 1, 2, 3) of macro elements (phosphorus, potassium and calcium) based on MS medium on bulblet regeneration percentage, bulblet number, bulblet fresh weight, scale explant fresh weight, and fresh weight of leaf and root was surveyed.
 
The results of the experiment clearly showed the effect of all three elements on the growth of bulblet, so that the limitation of any of the elements (0 strength) caused serious disorders in all explants.  With increasing the concentration of the studied elements, the bulblet regeneration percentage increased significantly. The maximum in vitro bulblet regeneration percentage (95.3 %) was found in explants grown on medium supplemented with double-strength of phosphorous. All three macroelementsnotably phosphorus played a major role on lily bulblets growth. According to results, application of double-strength of phosphorus caused the highest number of bulblet compared to test with 11.6. A considerable decrement in the fresh weight of leaves (16 g) and roots (10 g) was observed in the absence of calcium in the culture medium.
 
In general, phosphorus and calcium play a vital role in the regeneration of lily bulblets in vitro, so that on the one hand, double-strength of phosphorus had the highest amount of bulblet regeneration and fresh weight of the bulblets and on the other hand, shortage of calcium had the lowest amount in all parameters. So it is recommended to increase the concentrations of above mentioned macroelementsfor obtaining bigger bulblets.