Seed Set and Natural Regeneration of Dendrocalamus membranaceus Munro after Mass and Sporadic Flowering in Yunnan, China

Abstract

The flowering periods of woody bamboos, seed set, natural regeneration and death after flowering have been rarely observed and evaluated in the field. Dendrocalamus membranaceus Munro, a tropical woody bamboo mainly distributed in the Yunnan, displayed both sporadic as well as gregarious (mass) flowering and fruited from 2006 to 2013 following severe droughts. The aim of this study is to examine potential differences in seed set and natural regeneration between the two flowering patterns in natural D. membranaceus forests. We investigated and analyzed seed set, seed germination, seedling growth and mortality in both mass and sporadic flowering populations. Observations were made over a period of three years to record changes in bamboo seedling density, height and culm diameter. We observed a low natural seed set ranging from 1.76% to 7.49%, and a relatively high seed germination rate in the nursery from 59.6% to 71.0% for both types of flowering populations. Seeds germinated in 5–7 days after sowing and the germination period lasted 10–15 days. Seed set and germination rates in mass-flowering populations were significantly higher than those of sporadically flowering stands. The seedlings within sporadically flowering populations died within two years. In comparison, seedling mortality in the mass flowering population increased over two periods of observation from 64.92% to 98.89%, yet there was good seedling establishment left over, which showed mean height and mean culm diameter increasing by 1053.25% and 410.71%, respectively, in the second year of observations, and 137.10%, and 217.48%, respectively, in the third year. There are significant differences in seed set, natural regeneration ability and sustainability of bamboo populations between the mass flowering and sporadically flowering populations of D. membranaceus. Sporadic flowering populations failed to produce effective regeneration, while mass flowering populations were able to regenerate successfully. This study provides useful insights for conservation and natural forest management of D. membranaceus. We consider the merits of introducing other genetic provenances towards long-term maintenance of the stand features at sporadically flowering sites; meanwhile, the most economic option for mass flowering stands is to allow natural regeneration to take place through protecting such sites from further disturbance.

Bamboo Flowering from the Perspective of Comparative Genomics and Transcriptomics

“…For instance, in the case of gregarious flowering all the individuals of a species growing over a wide geographical area bloom within a brief interval of time, and then all die after flowering (Nadgauda et al, 1997; Bhattacharya et al, 2009; Marchesini et al, 2009; Austin and Marchesini, 2012; Chaubey et al, 2013; Xie et al, 2016). In contrast, for sporadic flowering only a few culms of a population flower at a time (Ramanayake and Yakandawala, 1998; Bhattacharya et al, 2006; Xie et al, 2016). Such a wide variation in flowering time and extent indicates that the plant group serves as a repository for a wide range of genes and expression patterns that support such a life style.…”

Mixed mating system and variable mating patterns in tropical woody bamboos

“…The above observations might be associated with the flowering clump (or pollen) densities and foraging behavior of pollinator (e.g. honeybees) of bamboo populations [16, 22, 23]. Woody bamboos are generally considered to be wind-pollinated, and some studies have demonstrated that Dendrocalamus spp.…”

“…3). Mass and sporadic flowering of D. membranaceus occurred from 2011 to 2015 [23]. In 2013, we selected two fixed sites (i.e., A and B) for observation and seed collection (Table 4).…”

“…As one of the regions with the most woody bamboo species in the world, Yunnan Province of China possesses more than 230 native species from 28 genera [10]. From 2008 to 2015, many bamboos experienced mass and sporadically flowering following a prolonged severe drought in Yunnan [22, 23]. In particular, the mass and sporadic flowering of Dendrocalamus membranaceus and sporadic flowering of D. sinicus were often observed [16, 22, 23] (Fig.…”

The Bamboo Flowering Cycle Sheds Light on Flowering Diversity

“…We investigated whether there is a relationship between the flowering habits of bamboo species and their taxonomic position at the genus level. We found that some genera, such as Arundinaria, Bambusa, Chimonobambusa, Dendrocalamus, Phyllostachys, Pleioblastus, and Schizostachyum, included sporadic, massive synchronized, and combined massive synchronized and sporadic flowering species (Bean, 1907;Jiao, 1956;Anonymous, 1961;Ram and Gopal, 1981;Zhou, 1984;Zhang and Ma, 1989;Pearson et al, 1994;Du et al, 2000;Li and Denich, 2004;Bhattacharya et al, 2006;Mao et al, 2008;Kitamura and Kawahara, 2009;Nath and Das, 2010;Sarma et al, 2010;Xu et al, 2012Xu et al, , 2014Tagle et al, 2013;Inoue et al, 2014;Xie et al, 2016;Zheng et al, 2016). Some bamboo genera, such as Fargesia, Indosasa, Pseudosasa, and Yushania, included sporadic and massive synchronized flowering species (Zhang and Ma, 1989;Du et al, 2000;Li and Denich, 2004;Jiang, 2007).…”