Litchi trees tend to exhibit alternate bearing after around 10 years of planting, more pronounced in the ‘China’ cultivar, whereas the ‘Shahi’ cultivar which is generally considered a regular bearer. A comparative analysis of biochemical compounds in the shoot buds of both cultivars revealed that ‘China’ litchi had lower levels of total carbohydrates and reducing sugars than the ‘Shahi’.“There is trend of decline in proline and phenol levels in shoot buds as the trees progresses from FBD to flowering stage, while total CHO and RS show incremental trend during the same period. It was also noticed that gibberellic acid (GA3), indole acetic acid (IAA) content was higher, Absiscic Acid (ABA), Zeatin (Z), Zeatin riboside (ZR) was lesser in shoot buds of litchi cv. China than in ‘Shahi’. Rather Di-hydro-zeatin riboside (DHZR) content is almost doubled in ‘China’ over ‘Shahi’ litchi. The flower inducing chemicals like paclobutrazol (PBZ) and potassium nitrate (KNO3) when applied on alternate bearer ‘China’ litchi, caused reduction in GA3 content with enhanced ABA and reduced IAA content in shoot buds, supplemented with improvement in cytokinin (CKs) (Z and ZR) contents. But in litchi cv. Shahi, GA3did not reduce but ABA level improved with increasing dose of PBZ. 2.0 g PBZ caused highest IAA and DHZR content in regular bearing cultivars. The endogenous hormones [in litchi cv. China], IAA improved by > 80%, GA3 decline by 70% in floral than in the non-floral shoots. In ‘Shahi’ litchi there was sharp decline in IAA (> 80%) and enhanced GA3 (> 30%) in floral shoots over non floral shoots because of PBZ. ABA played major role for flowering in litchi as the floral shoots recorded 20–30% higher ABA, over non-floral shoots in both the cultivars. The floral shoots also had higher concentration of CKs in terms of Z, ZR, DHZR than in non-floral shoots. In the litchi cv. China, GA3, IAA, ABA and Z, ZR, DHZR and iso-pentenyl adenine (iPA) was enhanced in floral shoots because of foliar spray of KNO3 (2%), PBZ (2.5 g), girdling and spray of salicylic acid, KH2PO4/or spermidine. The spray of prohexadione-Ca (0.5 g a.i. /L) during September month led to maximum ABA (95.45 µ g− 1FW) and KNO3 (2%) caused highest IAA in shoot buds. This suggests less GA3, high IAA, ABA and cytokinin in terms of ZR, DHZR is conducive for flowering in litchi cv. China while in ‘Shahi’ litchi, high GA3 with high ABA and cytokinin in terms of Z, ZR and iPA are pre-requisite for flowering.

The Endogenous Hormonal and Biochemical Status of Shoots Decide Transition from Vegetative to Reproductive Phases in Litchi (Litchi Chinensis Sonn.)

期刊论文
发表日期：

2026年1月5日

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Sanjay Kumar Singh,
Pragya Kumari,
Swati Sharma,
Vishal Nath

摘要

Litchi trees tend to exhibit alternate bearing after around 10 years of planting, more pronounced in the ‘China’ cultivar, whereas the ‘Shahi’ cultivar which is generally considered a regular bearer. A comparative analysis of biochemical compounds in the shoot buds of both cultivars revealed that ‘China’ litchi had lower levels of total carbohydrates and reducing sugars than the ‘Shahi’.“There is trend of decline in proline and phenol levels in shoot buds as the trees progresses from FBD to flowering stage, while total CHO and RS show incremental trend during the same period. It was also noticed that gibberellic acid (GA₃), indole acetic acid (IAA) content was higher, Absiscic Acid (ABA), Zeatin (Z), Zeatin riboside (ZR) was lesser in shoot buds of litchi cv. China than in ‘Shahi’. Rather Di-hydro-zeatin riboside (DHZR) content is almost doubled in ‘China’ over ‘Shahi’ litchi. The flower inducing chemicals like paclobutrazol (PBZ) and potassium nitrate (KNO₃) when applied on alternate bearer ‘China’ litchi, caused reduction in GA₃ content with enhanced ABA and reduced IAA content in shoot buds, supplemented with improvement in cytokinin (CKs) (Z and ZR) contents. But in litchi cv. Shahi, GA₃did not reduce but ABA level improved with increasing dose of PBZ. 2.0 g PBZ caused highest IAA and DHZR content in regular bearing cultivars. The endogenous hormones [in litchi cv. China], IAA improved by > 80%, GA₃ decline by 70% in floral than in the non-floral shoots. In ‘Shahi’ litchi there was sharp decline in IAA (> 80%) and enhanced GA₃ (> 30%) in floral shoots over non floral shoots because of PBZ. ABA played major role for flowering in litchi as the floral shoots recorded 20–30% higher ABA, over non-floral shoots in both the cultivars. The floral shoots also had higher concentration of CKs in terms of Z, ZR, DHZR than in non-floral shoots. In the litchi cv. China, GA_3, IAA, ABA and Z, ZR, DHZR and iso-pentenyl adenine (iPA) was enhanced in floral shoots because of foliar spray of KNO₃ (2%), PBZ (2.5 g), girdling and spray of salicylic acid, KH₂PO₄/or spermidine. The spray of prohexadione-Ca (0.5 g a.i. /L) during September month led to maximum ABA (95.45 µ g^− 1FW) and KNO₃ (2%) caused highest IAA in shoot buds. This suggests less GA₃, high IAA, ABA and cytokinin in terms of ZR, DHZR is conducive for flowering in litchi cv. China while in ‘Shahi’ litchi, high GA₃ with high ABA and cytokinin in terms of Z, ZR and iPA are pre-requisite for flowering.