Guastella Devid, Sigwebela Mbuyseli, Suarez Eloy, Stubbs Oscar, Acevedo Jorge, Engelbrecht Gerhard
Agrisudafrica (Pty) Ltd., Franklin, South Africa.
Ferrero Hazelnuts Company, Division of Ferrero Trading Luxembourg, Senningerberg, Luxembourg.
Front Plant Sci. 2020 Dec 10;11:602766. doi: 10.3389/fpls.2020.602766. eCollection 2020.
Hazelnut ( L.) is one of the most appreciated nut crops, which is motivating the cultivation outside its historical production areas. Despite that, there is still limited knowledge about the floral biology of the species and its developmental fruiting stages under different environments. Adverse climatic conditions can threaten the pollination process and fruit development. In South Africa, the deciduous fruit industry identified the net shading as a tool to mitigate the effects of unfavorable abiotic events. The objective of this work was to investigate the effects of photo-selective nets on the pollination process and nut development of . Mature hazelnut trees were maintained under netting and compared with the ones in open field. Microscopic examination of female flower and developing nuts were conducted in order to observe the pollen tube growth and the pattern of disodium fluorescein transport into the funiculus and ovule. The results showed differences in pollen tubes growth and timing between the treatments. Generally, trees under nets showed higher rate in pollen tubes developing and reaching the base of the style. On the contrary, the tests carried out in open field showed a higher ratio of pollen tubes arrested in the style. The results also indicated differences in ovules abortion. Developing fruits that showed an interruption point at the funicle level or at junction point of the ovule were classified as aborting fruits (blank nuts at harvest time). A higher rate of abortion was detected in open field compared to the plants under netting. In conclusion, the shade nets influenced the pollen tube growth and the nut development, principally due to micro-climate modification. Therefore, further investigations are needed to analyze the influence of light spectra and to determine the sustainability of photo-selective nets over several years.
榛子（L.）是最受青睐的坚果作物之一，这促使其在历史产区以外的地区进行种植。尽管如此，对于该物种的花生物学及其在不同环境下的果实发育阶段，人们仍然了解有限。不利的气候条件会威胁授粉过程和果实发育。在南非，落叶果树产业将遮阳网视为减轻不利非生物事件影响的一种手段。这项工作的目的是研究光选择性网对榛子授粉过程和坚果发育的影响。将成熟的榛子树置于网下，并与露天种植的树进行比较。对雌花和发育中的坚果进行显微镜检查，以观察花粉管的生长以及荧光素二钠向珠柄和胚珠的运输模式。结果表明，不同处理之间花粉管生长和时间存在差异。一般来说，网下的树花粉管发育并到达花柱基部的速率更高。相反，在露天进行的测试表明，花粉管在花柱中停滞的比例更高。结果还表明胚珠败育存在差异。在珠柄水平或胚珠连接处出现中断点的发育中果实被归类为败育果实（收获时为空壳坚果）。与网下种植的植株相比，露天种植的植株败育率更高。总之，遮阳网影响了花粉管生长和坚果发育，主要是由于微气候的改变。因此，需要进一步研究来分析光谱的影响，并确定光选择性网在多年内的可持续性。
