Position Effect Of The Leaf Stalks From Pinellia Ternate (Thunb.) Berit. And Its Influencing Factors

Pinellia ternata (Thunb.) Briet. is a perennial medical plant of araceae. Their tubersare used as a crude drug of traditional Chinese medicine. The microtubers from P. ternataleaf stalks is not by differentiation but formed directly. When leaf stalks were insertedupside down in the MS media, all the microtubers were grew in the upper ends. Fiveendogenous hormones (IAA,GA₃,ABA,ZR and JA) of the upper ends were detectedwith Enzyme-linked Immunosorbent Assays (ELISA) during the formation of microtu-bers. The results showed that the content of endogenous hormones IAA,ABA,ZR andJA increased which were assumed to excite basically the formation of the microtubers invitro. But the content of GA₃ decreased greatly in the initial formation of microtubers.Furthermore, along with the formation of microtubers from the petiole, the ratio ofIAA/GA₃,ABA/GA₃,ZR/GA₃ and JA/GA₃ increased first and then decreased after 15days. The values of IAA/GA₃,ABA/GA₃,ZR/GA₃ and JA/GA₃ remained at high levelduring the rapid formation of the tuber. And the values of JA/GA₃ increased after 20 days.The position of tubers changed when different concentration of IAA was added in theMS media. To probe the relationship between Auxin polar Transport and location ofmicrotubers, experments were designed as follows:1. P. ternata leaf stalks were inserted upside up and down in the MS media withdifferent concentrations of IAA. The representative media were selected through theobservation of morphology. Results and conclusions: When the leaf stalks were insertedupside up, the forms number of the microtubers in the upper ends were increased firstthen reduced with the IAA concentrations increased. When the leaf stalks were insertedupside down, the result was reversed. Statistic analysis showed that the MS and the MS-1media are best for the position effect. In the MS media, when the leaf stalks were insertedupside up, 80% microtubers were grew in the upper ends, and all the microtubers weregrew in the upper ends when the leaf stalks were inserted upside down; In the MS-1media, 86% microtubers were grew in the upper ends when the leaf stalks were insertedupside up, and when the leaf stalks were inserted upside down, 92% microtubers weregrew in the upper ends.2. P. ternata leaf stalks were inserted upside up in the MS,BXK(MS+6-BA 2 mg/L+IAA 1mg/L) and MS-1(MS+IAA 1.5mg/L) media with different concentra tions ofauxin polar transport inhibitors (NPA and HFCA) and mineral substance element Ca²⁺ and B³⁺. And their effects on the position effect of the leaf stalks were observed throughthe morphology and endogenous hormones.From the morphology observation, in the comparison MS media, most of the leafstalks that inserted upside up grew in the upper ends. In the MS media added with NPAand HFCA, most of the microtubers from the leaf stalks that inserted upside up grew inthe upper ends, and the number of the microtubers in the upper ends were increased firstthen reduced with the inhibitor concentrations increased. When the concentration of NPAwas 4μmol/L, HFCA was 40μmol/L, the forms number of microtubers from the upperends were most; In the BXK media (Ca²⁺ was 3 mmol/L), 10% microtubers from the leafstalks that inserted upside down grew in the upper ends; Under low and high concentratedof Ca²⁺ the position effect of the p. ternata microtubers received affects, when concentr-ation of Ca²⁺ was 1.5 mmol/L and 8 mmol/L, the affects seemed obviously, most of themicrotubers from the leaf stalks were grew in the upper ends, the maximum efficiencyinduction is 87%; In the comparison media added with B³⁺ (0.1 mmol/L), 87%microtubers from the leaf stalks that inserted upside down grew in the upper ends; Underlow concentrated B³⁺ the position effect of the P. ternata microtubers received affects,when concentration of B³⁺ was 0.08 mmol/L, the affects seemed obviously, most of themicrotubers from the leaf stalks were grew in the lower ends, the maximum efficiencyinduction is 85%; Under high concentrated B³⁺ the position effect seemed normal.The determination of the level of the endogene hormone showed that the differenceconcentration of IAA between the both sides determined the position of the microtubers,that is the formation of of the microtubers was determined by the lower concentration ofIAA. In the MS media, the IAA concentration was lower in the upper ends, then the leafstalks grew in the upper ends. When the NPA concentration was 4μmol/L, HFCAconcentration was 40μmol/L, the IAA concentration was lower in the upper ends, andthen 80% leaf stalks grew in the upper ends; in the BXK media, the concentrations ofIAA in the upper ends is higher than the lower ends, most of the microtubers from theleaf stalks were grew in the lower ends. When Ca²⁺ concentration was 1.5 mmol/L and 8mmol/L, the concentrations of IAA in the upper ends is lower than the lower ends, mostof the microtubers from the leaf stalks were grew in the upper ends; in the MS-1 media,the concentrations of IAA in the upper ends is lower than the lower ends, most of themicrotubers from the leaf stalks were grew in the upper ends. When concentration of B³⁺was 0.08 mmol/L, the concentrations of IAA in the lower ends is lower than the upperends, most of the microtubers from the leaf stalks were grew in the lower ends. So, all the result told us: auxin polar transport inhibitors (NPA and HFCA) is essentialfor the inhibition of auxin polar transport and the formation of position effect ofmicrotubers, mineral substance element calcium and boron play a direct or indirect role inthe mechanism action of the auxin polar transport, with the suitable concentration, Ca²⁺and B³⁺ seemed effectly on the position effect of microtubers in P. ternata.