种间竞争对香蒲与芦苇生长的影响

为了探究种间竞争对香蒲（Typha domingensis）与芦苇（Phragmites australis）生长的影响，利用根系分隔盆栽试验研究了3种不同分隔方式条件下香蒲与芦苇的种间竞争特性，包括塑料膜分隔（根系完全分隔，无相互作用，无物质交换）、尼龙网分隔（根系部分分隔，无相互作用，有物质交换）和不分隔（根系完全相互作用，有物质交换），分析了香蒲与芦苇根系形态和地上部生长的变化，探究香蒲与芦苇种间竞争的差异。结果发现（1）在尼龙网分隔和不分隔处理中芦苇具有明显的劣势。与塑料膜分隔处理相比，芦苇的总生物量、植株密度在尼龙网分隔和不分隔处理中分别减少了39.14%、49.41%和82.08%、79.22%，总根长、总根表面积、总根体积分别减少了40.53%、44.84%、62.52%和85.7%、82.45%、89.67%，且均具有极显著差异（P<0.01）；根系分隔方式也影响芦苇的株高、茎粗和叶片数，表现为不分隔 > 塑料膜分隔 > 尼龙网分隔。（2）与塑料膜分隔处理相比，香蒲总生物量在尼龙网分隔和不分隔中虽有增加，但差异不显著，植株密度和株高在尼龙网分隔和不分隔处理中都有增加且具有显著差异（P<0.05），其总根长、总根表面积、总根体积在尼龙网分隔中分别增加了57.93%、26.5%、8.04%，但在不分隔处理中分别减少了11.57%、14.92%、11.39%（P<0.05），虽然根系的相互作用对香蒲根系的生长具有促进作用，但植物种间根系相互作用越强，对两者的生长越不利。（3）在不同的分隔方式中，芦苇与香蒲间也存在明显变化。在不分隔处理中，香蒲的生物量和植株密度是芦苇的1.7倍和6.74倍，与塑料膜分隔处理相比增加了6倍，表明芦苇与香蒲根系的完全相互作用，显著削减了芦苇的繁殖生长，增加了香蒲的根系分蘖。（4）通过种间相互作用强度（RII值）分析也表明，尼龙网分隔和不分隔处理下芦苇表现为抑制作用（RII值为负值），香蒲表现为促进作用（RII值为正值）。香蒲与芦苇互作对芦苇具有抑制作用，说明种间相互作用是能改变植物的适应性和植物群落的繁殖，同时也表明植物根系不仅在吸收土壤中的水和养分中起着关键作用，在种间关系中也起着重要作用。因此利用种间竞争控制植物生长，可以为保护生物多样性和生态系统的功能提供有效的技术支撑。

Effects of interspecific competition on the growth of Typha domingensis and Phragmites australis

In order to investigate the effects of interspecific competition on the growth of Typha domingensis and Phragmites australis, a pot experiment technique was designed to study the interspecific competition characteristics of T. domingensis and P. australis under different root barriers, including plastic barrier (complete root separation, no interaction and no substance exchange), nylon mesh barrier (partial root separation, no interaction and substance exchange) and no barrier (no root separation, root interaction and substance exchange). The root morphological characteristics and above-ground growth were analyzed to explore the differences of interspecific competition between T. domingensis and P. australis. Results showed that (1) P. australis had obvious disadvantage in nylon mesh barrier and no barrier treatment. Compared with plastic barrier, the total biomass, plant density were 39.14%, 49.41% and 82.08%, 79.22%, total root length, root surface area and root volume of P. australis were 40.53%, 44.84%, 62.52% and 85.7%, 82.45%, 89.67% significantly lower under nylon mesh barrier and no barrier treatment, respectively. And plant height, stem diameter and leaf number in our study were affected by root barrier treatments, following the order of no barrier > plastic barrier > nylon mesh barrier. (2) The total biomass of T. domingensis in the nylon mesh barrier and no barrier treatment was higher than those in plastic barrier treatment, but the difference was not significant. However, Plant density and plant height of T. domingensis in the nylon mesh barrier and no barrier treatment were higher than those in plastic barrier treatment, and the difference was significant (P<0.05). Compared to plastic barrier, the total root length, root surface area and root volume of T. domingensis were increased by 57.93%, 26.5% and 8.04% in nylon mesh barrier, respectively, but decreased by 11.57%, 14.92% and 11.39% in no barrier treatment, respectively (P<0.05). Although the interaction of root promoted the growth of the root of T. domingensis, and the roots interaction are stronger, more disadvantageous to the growth of them. (3) In different root barriers treatment, obvious changes were also found between T. domingensis and P. australis. In no barrier treatment, the biomass and the plant density of T. domingensis were 1.7 times and 6.74 times higher than that in P. australis, and increased 6 times compared with plastic barrier. The study indicated that the roots interaction between T. domingensis and P. australis significantly weakened the reproductive growth of P. australis, and increased the root tillers of T. domingensis. (4) The interspecific interaction index (RII) analysis also showed that P. australis exhibited inhibitory effect (RII was negative) and T. domingensis exhibited promoting effect (RII was positive) under nylon mesh barrier and no barrier. The root interactions can inhibit P. australis, which has a strong impact on plant adaptation and plant community reproduction. It also shows that root not only play a key role in uptake of water and nutrients from soil, but also play an important role in interspecific relationships. The results provide a technical support for the biodiversity conservation and protect the ecosystem function by controlling the growth of P. australis through interspecific competition.