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Background The transmitting tissue of the style is the pathway for pollen tube growth to the ovules and has components that function in recognizing and discriminating appropriate pollen genotypes. In Nicotiana tabacum , the class III pistil extensin-like (PELPIII) arabinogalactan protein is essential for the inhibition of N. obtusifolia pollen tube growth. The transmitting tissue-specific (TTS) arabinogalactan protein amino acid sequence and expression pattern is similar to PELPIII, but it facilitates self-pollinated N. tabacum . The TTS and PELPIII arabinogalactan protein can be divided into the less conserved N-terminal (NTD) and the more conserved C-terminal (CTD) domains. This research tested whether the NTD is the key domain in determining PELPIII function in the inhibition of interspecific pollen tube growth. Three variant PELPIII gene constructs were produced where the PELPIII NTD was exchanged with the TTS NTD and a single amino acid change (cysteine to alanine) was introduced into the PELPIII NTD. The PELPIII variants of N. tabacum were tested for activity by measuring the inhibition N. obtusifolia pollen tube growth by using them to complement a 3’UTR RNAi transgenic line with reduced PELPIII mRNA. Results The RNAi N. tabacum line had reduced PELPIII mRNA accumulation and reduced inhibition of N. obtusifolia pollen tube growth, but had no effect on self-pollen tube growth or pollen tube growth of 12 other Nicotiana species. The NTD of PELPIII with either the PELPIII or TTS CTDs complemented the loss PELPIII activity in the RNAi transgenic line as measured by inhibition of N. obtusifolia pollen tube growth. The TTS NTD with the PELPIII CTD and a variant PELPIII with a cysteine to alanine mutation in its NTD failed to complement the loss of PELPIII activity and did not inhibit N. obtusifolia pollen tube growth. Conclusion The NTD is a key determinant in PELPIII’s function in regulating interspecific pollen tube growth and is a first step toward understanding the mechanism of how PELPIII NTD regulates pollen tube growth. Electronic supplementary material The online version of this article (10.1186/s12870-019-1728-8) contains supplementary material, which is available to authorized users.

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LESSA, M. A. et al. 950Ciênc. agrotec., Lavras, v. 33, n. 4, p. 950-955, jul./ago. 2009 ABSTRACT Succulents present great commercial importance, but information on the cultivation of these plants are not enough, especially considering the use of fertilizers during the growth phase. The objective of this study was to evaluate the effect of different fertilizers applied to the substrate in the cultivation of Kalanchoe luciae Raym.-Hamet. Cuttings measuring 6 cm in height and 12 cm in diameter were cultivated in 1.5 L pots containing the substrate (1 soil: 1 sand: 1 vermiculite). In this experiment, the effect of the fertilization based on NPK 10:10:10 was evaluated with and without the addition of a fertilizer mixture composed of 5 g bone flour, 5 g dolomite limestone, and 50 g ground charcoal, this proportion that was used for each 1.5 L substrate. After 60 days, an increase in the number of leaves, which was proportional to the increase in the doses of NPK applied, was verified. Even though the plants presented higher number of leaves (18.34) and higher height (18.73 cm) for the substrate with 1.5 g L -1 of NPK 10:10:10, plants did not reach the compact aspect suggested by some producers. The addition of fertilizer mixture presented no effect on the leaves number and neither to the plant height, however, it was observed that the plants that received the fertilizer mixture presented the fifth leaf with bigger diameter. None of the treatments favored the formation of one of the most important characteristics of this species, the reddish color on the borders of the leaves. APPLICATION OF DIFFERENT FERTILIZERS IN SUBSTRATE FOR Index terms:Crassulaceae, fertilization, ornamental plants. RESUMOAs suculentas apresentam grande importância comercial, mas, as informações sobre o cultivo destas plantas ainda são escassas, especialmente em relação à fertilização durante a fase de crescimento. Neste trabalho, objetivou-se avaliar o efeito de diferentes adubações no substrato para cultivo de Kalanchoe luciae Raym.-Hamet. Mudas com 6 cm de altura e 12 cm de diâmetro foram cultivadas em vasos de 1,5 L, contendo o substrato (1 terra:1 areia: 1 vermiculita). Avaliou-se, nesse experimento, o efeito de adubações à base de NPK 10:10:10, com e sem adição de uma mistura de adubos composta de 5 g de farinha de osso, 5 g de calcário dolomítico e 50 g de carvão vegetal triturado, proporção essa, utilizada para cada 1,5 L de substrato. Após 60 dias, verificou-se que o aumento do número de folhas foi proporcional ao aumento das doses de NPK aplicadas. Apesar de apresentarem maior número de folhas (18,34) e maior altura das plantas (18,73 cm) para o substrato com 1,5 g L -1 de NPK 10:10:10 as plantas não atingiram o aspecto compacto sugerido por alguns produtores. Não houve efeito da adição da aplicação da mistura de adubos sobre o número de folhas formadas e altura da planta, entretanto, observou-se que as plantas que receberam a mistura de adubos apresentaram maior diâmetro da 5ª folha. Nenhum dos tratamentos favoreceu a formação de u...

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