Liu Yongjie, Ying Zhixia, Wang Shichang, Liao Jinbao, Lu Hui, Ma Liang, Li Zhenqing
State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China.
Department of Biology Centre of Excellence Plant and Ecosystem University of Antwerp Wilrijk Belgium.
Ecol Evol. 2017 Jul 3;7(16):6284-6291. doi: 10.1002/ece3.3214. eCollection 2017 Aug.
Masting is defined as the intermittent highly variable production of seed in a plant population. According to reproductive modes, that is, sexual and asexual reproduction, masting species can be separated into three groups, that is, (1) species, for example, bamboo, flower only once before they die; (2) species, for example, , reproduce sexually; and (3) species, for example, , reproduce both sexually and asexually. Several theories have been proposed to explore the underlying mechanisms of masting. However, to our knowledge, no theory has been found to explain the mechanism of masting species that reproduce both sexually and asexually. Here we refine the Resource Budget Model by considering a trade-off between sexual and asexual reproduction. Besides the depletion efficient (i.e., the ratio of the cost of seed setting and the cost of flowering), other factors, such as the annual remaining resource (i.e., the rest of the resource from the photosynthetic activity after allocating to growth and maintenance), the trade-off between sexual and asexual reproduction, and the reproductive thresholds, also affect masting. Moreover, two potential reproductive strategies are found to explain the mechanisms: (1) When the annual remaining resource is relatively low, plants reproduce asexually and a part of the resource is accumulated as the cost of asexual reproduction is less than the annual remaining resource. Plants flower and set fruits once the accumulated resource exceeds the threshold of sexual reproduction; (2) when the annual remaining resource is relatively high, and the accumulated resource surpasses the threshold of sexual reproduction, masting occurs. Remarkably, under certain depletion efficient, more investigation in sexual reproduction will lead plants to reproduce periodically. Additionally, plants investigate less resource to reproduce periodically when depletion efficient keeps increasing as plants can reproduce efficiently. Overall, our study provides new insights into the interpretation of masting, especially for species that reproduce both sexually and asexually.
大年结实被定义为植物种群中种子间歇性的高变异性生产。根据繁殖方式，即有性繁殖和无性繁殖，大年结实物种可分为三类：（1）像竹子这样的物种，在死亡前只开花一次；（2）像[此处原文缺失具体物种]这样的物种，进行有性繁殖；（3）像[此处原文缺失具体物种]这样的物种，既进行有性繁殖也进行无性繁殖。已经提出了几种理论来探索大年结实的潜在机制。然而，据我们所知，尚未发现能解释既进行有性繁殖又进行无性繁殖的大年结实物种机制的理论。在此，我们通过考虑有性繁殖和无性繁殖之间的权衡来完善资源预算模型。除了消耗效率（即结实成本与开花成本的比率）外，其他因素，如年度剩余资源（即分配给生长和维持后光合作用活动剩余的资源）、有性繁殖和无性繁殖之间的权衡以及繁殖阈值，也会影响大年结实。此外，还发现了两种潜在的繁殖策略来解释其机制：（1）当年度剩余资源相对较低时，植物进行无性繁殖，并且由于无性繁殖成本低于年度剩余资源，一部分资源会积累起来。一旦积累的资源超过有性繁殖阈值，植物就会开花结果；（2）当年度剩余资源相对较高且积累的资源超过有性繁殖阈值时，就会出现大年结实现象。值得注意的是，在一定的消耗效率下，对有性繁殖投入更多研究将导致植物周期性繁殖。此外，当消耗效率持续增加时，植物为了能高效繁殖，会减少用于周期性繁殖的资源投入。总体而言，我们的研究为大年结实的解释提供了新的见解，特别是对于既进行有性繁殖又进行无性繁殖的物种。
