Growth, Plastochron, and the Final Number of Nodes of China Pink Seedlings Grown on Different Substrates

Marília Milani,Nereu Augusto Streck,Juliano Dalcin Martins,Sidinei José Lopes

doi:10.1590/0034-737x201764040010

Abstract

ABSTRACT The objective of this work was to plot the growth curves and determine the plastochron and the final number of nodes of China pink seedlings grown on different substrates. Thus, 392 China pink seedlings were grown on seven substrates under greenhouse conditions, in Santa Maria in the state of Rio Grande do Sul, Brazil. The growth curves were plotted using the logistic model. The plastochron was estimated by the inverse of the angular coefficient of the simple linear regression between the number of accumulated nodes and accumulated thermal sum from the subsampling of the seedlings. In all substrates, the logistic model fit better for the variable number of leaves than for the plant height. The plants in substrates with 50% of soil plus 50% of rice husk ash, and 80% of rice husk ash plus 20% earthworm humus had the longest cycles with 74 and 65 days, respectively. They completed the cycles with a thermal sum of 1317.9 ºC day for number of leaves and plant height. The growth curves that were plotted by the logistic model and the plastochron of the China pink seedlings are dependent on the type of substrate used. The commercial substrate Mecplant® had the best results. The average final number of nodes of the main stem of the plants was 14 for all substrates.

Highlights

Dianthus chinensis L. (China pink) is a plant species that can be used in a garden, or the flowers can be cut for bouquets
China pink seedlings are grown on substrates until the point of sale when the first flower bud opens, and they are directed to commercial centers
Twenty-eight-day old Dianthus chinensis L. (Dianthus F1 Diamond) seedlings were obtained from a specialized company, and they were subsampled into these containers with approximately three pairs of leaves and a height of 2.5 cm

Summary

Introduction

Dianthus chinensis L. (China pink) is a plant species that can be used in a garden, or the flowers can be cut for bouquets. (China pink) is a plant species that can be used in a garden, or the flowers can be cut for bouquets. China pink has an early and abundant flowering, with excellent performance in spring and autumn (Sakata Seed Sudamérica Ltda®, 2012), when there is less choice of floriferous species intended for these uses. China pink seedlings are grown on substrates until the point of sale when the first flower bud opens, and they are directed to commercial centers. The production of high-quality China pink seedlings is very important because their performance at this stage will determine the development of the crop to produce a suitable final product to create gardens. Substrate formulations are evaluated according to the needs of the cultivated species to ensure the mechanical maintenance of the root system and plant stability. Substrates must provide the liquid phase for water and nutrient supply and the gas phase for oxygen supply and transport of carbon dioxide to the roots (Silveira et al, 2002)

Objectives

Methods

Results