El-Diehy Mahmoud A, Farghal Ibrahim I, Amin Mohamed A, Ghobashy Mohamed Mohamady, Nowwar Abdelatti I, Gayed H M
Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt.
Radiation Research of Polymer Chemistry Department, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt.
Sci Rep. 2025 Jan 11;15(1):1661. doi: 10.1038/s41598-024-83832-3.
This study investigates the negative impact of climate change on water resources, specifically water for agricultural irrigation. It describes how to optimize swelling, gel properties and long-term water retention capacities of Na-CMC/PAAm hydrogels for managing drought stress of Sugar beet plants through techniques such as changing the composition, synthetic conditions and chemical modification. Gamma radiation-induced free radical copolymerization was used to synthesize superabsorbent hydrogels using sodium carboxymethyl cellulose (Na-CMC) and acrylamide (AAm). The study also explored how varying Na-CMC/AAm ratio and radiation dose influence their swelling behaviour, gel fraction, and water retention. FTIR showed that CMC and PAAm components are part of the hydrogel structure. The equilibrium swelling reached a maximum value of ~ 500 g/g at a Na-CMC/AAm ratio of 60/40. High content of AAm reduced swelling because it caused increased hydrophobicity while high radiation doses up to 50 kGy increased crosslinking resulting in improved but limited swelling from 65 to 85 (g/g). After the second cycle, KOH modification reached maximum swelling capacity by introducing anionic carboxylate groups up to 415 (g/g). SEM images revealed uniform pores in an unmodified scaffold while larger cavities were formed upon modification facilitating Water absorption. Surprisingly, the improved hydrogels retained more water: about 75% even after 16 days as opposed to a 50% drop within five days in the case of unmodified ones. This hydrogel significantly enhanced shoot length by 18%, root length by 32%, fresh weight shoot by 15%, and dry weight shoot by 15% under severe drought conditions. As a result, yield increased by 22%, proteins went up by 19%, and carbohydrates rose by 13%. Leaf chlorophyll content increased with a corresponding decline in stress enzymes indicating decreased oxidative damage. This eco-friendly Na-CMC/PAAm-based hydrogel seems to have potential use for addressing water scarcity and agricultural challenges.
本研究调查了气候变化对水资源，特别是农业灌溉用水的负面影响。它描述了如何通过改变组成、合成条件和化学改性等技术来优化羧甲基纤维素钠/聚丙烯酰胺（Na-CMC/PAAm）水凝胶的溶胀、凝胶特性和长期保水能力，以应对甜菜植物的干旱胁迫。采用γ辐射诱导自由基共聚法，以羧甲基纤维素钠（Na-CMC）和丙烯酰胺（AAm）为原料合成了高吸水性水凝胶。该研究还探讨了不同的Na-CMC/AAm比例和辐射剂量如何影响其溶胀行为、凝胶分数和保水能力。傅里叶变换红外光谱（FTIR）表明，CMC和PAAm组分是水凝胶结构的一部分。在Na-CMC/AAm比例为60/40时，平衡溶胀达到最大值，约为500 g/g。高含量的AAm会降低溶胀，因为它会导致疏水性增加，而高达50 kGy的高辐射剂量会增加交联，从而使溶胀得到改善，但受到限制，从65增加到85（g/g）。在第二个循环后，KOH改性通过引入阴离子羧酸盐基团达到最大溶胀能力，高达415（g/g）。扫描电子显微镜（SEM）图像显示，未改性的支架中有均匀的孔隙，而改性后形成了更大的空洞，有利于吸水。令人惊讶的是，改进后的水凝胶保留了更多的水分：即使在16天后仍保留约75%，而未改性的水凝胶在五天内水分含量下降了50%。在严重干旱条件下，这种水凝胶显著提高了茎长18%、根长32%、地上部鲜重15%和地上部干重15%。结果，产量提高了22%，蛋白质含量提高了19%，碳水化合物含量提高了13%。叶片叶绿素含量增加，应激酶相应减少，表明氧化损伤降低。这种基于Na-CMC/PAAm的环保型水凝胶似乎具有解决水资源短缺和农业挑战的潜在用途。
