Morphology of strobili at different development positions and cone and seed characteristics of Pinus densiflora f. multicaulis

Abstract

Pinus densiflora f. multicaulis is a rare and unusual form of genus Pinus. It has excellent ornamental values due to many trunks from its root collar, and produces female, male, and bisexual strobili on thes ame tree. However, there is limited study whether the bisexual strobili are functional, mature lateral conesproduce filled seeds, and the seeds from the mature lateral cones germinate and grow as well as those frommature apical cones. The structure of apical female, and lateral male and bisexual strobili were analyzed in an open-pollination-progeny population. The strobili were photographed to obtain external, cross-section, and radial-section images using a 45× stereoscopic microscope. Radial sections of strobili were imaged using scanning electron microscopy. Characteristics of apical and lateral cones and seeds were surveyedby cone analysis and germination test. P. densiflora f. multicaulis developed typical female strobili apically,and ordinary male and bisexual strobili laterally. Additionally, female strobili developed laterally whereas the male strobili were normally located. The mature lateral female strobili had the same structure as the apical female. In the mature bisexual strobili, the proportion of male and female tissue was unequal. The cones developed from lateral female strobili showed highly significant differences in the length, width, and weight, being shorter (32.7%), narrower (26.9%), and lighter (59.8%) than those from apical female strobili. Both types produced filled seeds and seedlings, and well significant positive correlations were found among characteristics of seeds from apical and lateral female strobili. The initial seed germination rate of the seeds from apical female strobili was higher than that of seeds from lateral female strobili, but the difference decreased over time. The viability and spatial distribution of the female and male tissue of bisporangiate cones, and their frequent occurrence suggests a common mechanism for the production of bisporangiate structures in seed plants.

Reciprocal expression of MADS-box genes and DNA methylation reconfiguration initiate bisexual cones in spruce

“…In case where female structures occupy a small proportion, the bisexual cones will dry and drop without seed production. In contrast, if the female structures occupy a large proportion, the bisexual cones can produce seeds, as reported in Abies balsamea, Pinus densiflora f. multicaulis, P. johannis, and P. tabuliformis 19,23,37,38 . This implies that bisexual cones may not necessarily be deleterious and nonfunctional.…”

Widely Targeted Metabolomic Profiling Combined with Transcriptome Analysis Provides New Insights into Lipid Biosynthesis in Seed Kernels of Pinus koraiensis

“…They are often globular or spike-shaped and affixed to the tips of leaves or branches. The primary source of energy for plants to transition from vegetative growth to reproductive growth are the reserves stored in branches and needles [ 42 , 43 ]. Enzymes [ 44 ], hormones [ 45 ], and gene expression [ 46 ] are other important elements in the development of seeds in addition to environmental factors.…”