van Wesemael Jelle, Kissel Ewaut, Eyland David, Lawson Tracy, Swennen Rony, Carpentier Sebastien
Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Leuven, Belgium.
School of Biological Sciences, University of Essex, Colchester, United Kingdom.
Front Plant Sci. 2019 Mar 26;10:352. doi: 10.3389/fpls.2019.00352. eCollection 2019.
Water deficit is one of the world's major constraints in agriculture and will aggravate in the future. Banana ( spp.) is an important crop that needs vast amounts of water for optimal production. The International Transit Center of Bioversity International holds the world's biggest collection of banana biodiversity (>1,500 accessions). The long-term aim of this research is to evaluate the potential within this collection for climate smart agricultural usage. Therefore, we developed a phenotyping setup under controlled environmental conditions and we selected 32 representatives of the biodiversity (29 cultivars and 3 wild relatives) for evaluation. The best performing genotypes accumulated six to seven times more biomass than the least performing. Eight genotypes (five ABB, one AAB, and two AAA) invest under osmotic stress significantly more in root growth than in leaf growth. We predict therefore that these genotypes have potential for high productivity under rain fed conditions with a short dry season. To gain more insight in the transpiration physiology, we gravimetrically monitored individual plant transpiration over the diurnal period. All analyzed genotypes showed a marked reduction in transpiration rate in the afternoon. Moreover, the timing of this onset, as well as its impact on total transpiration, was genotype dependent. This phenomenon was more pronounced in 13 genotypes (eight ABB, two AAB, two AA, one BB). Banana is a crop originating from the humid tropics and has developed a strong root pressure to maintain an efficient water and nutrient transport even under saturated relative humidity conditions. Therefore, we hypothesize that the diurnal transpiration decline contributes to a higher water use efficiency without compromising the nutrient transport. Of the eight genotypes that had the best growth under osmotic stress, all analyzed ABB cultivars have a lower maximal transpiration rate, keep this maximal transpiration for a shorter time and therefore consume less water per day. We conclude that lab models are very useful to study the biodiversity and to identify different traits that contribute to a better drought tolerance/avoidance. We encourage researchers investigating other crops to start exploring their collections.
水分亏缺是世界农业面临的主要限制因素之一，且未来情况会加剧。香蕉（ spp.）是一种重要作物，最佳产量需要大量水分。国际生物多样性中心的国际中转中心保存着世界上最大的香蕉生物多样性种质库（超过1500份种质）。本研究的长期目标是评估该种质库用于气候智能型农业的潜力。因此，我们在可控环境条件下建立了一个表型分析平台，并从生物多样性中挑选了32个代表（29个栽培品种和3个野生近缘种）进行评估。表现最佳的基因型积累的生物量比表现最差的多6到7倍。8个基因型（5个ABB、1个AAB和2个AAA）在渗透胁迫下，根系生长的投入显著多于叶片生长。因此，我们预测这些基因型在旱季较短的雨养条件下具有高产潜力。为更深入了解蒸腾生理，我们通过重量法监测了单株植物在白天的蒸腾情况。所有分析的基因型在下午蒸腾速率均显著降低。此外，这种变化开始的时间及其对总蒸腾量的影响因基因型而异。这一现象在13个基因型（8个ABB、2个AAB、2个AA、1个BB）中更为明显。香蕉起源于湿润的热带地区，即使在相对湿度饱和的条件下，也能形成强大的根压以维持高效的水分和养分运输。因此，我们推测白天蒸腾量的下降有助于提高水分利用效率，同时不影响养分运输。在渗透胁迫下生长最佳的8个基因型中，所有分析的ABB品种最大蒸腾速率较低，且维持最大蒸腾的时间较短，因此每天耗水量较少。我们得出结论，实验室模型对于研究生物多样性以及识别有助于提高耐旱性/避旱性的不同性状非常有用。我们鼓励研究其他作物的研究人员开始探索他们的种质库。
